Update javaxval/src/test/java/org/baeldung/javaxval/messageinterpolator/ParameterMessageInterpolaterIntegrationTest.java

update to use the givenX_whenY_thenZ naming convention for tests

Co-Authored-By: KevinGilmore <kpg102@gmail.com>

javax-servlets/.gitignore

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+# Created by .ignore support plugin (hsz.mobi)
+.idea
+classes
+target
+*.iml
+out

javax-servlets/README.md

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+## Servlets
+
+This module contains articles about Servlets.
+
+### Relevant Articles:
+- [Introduction to Java Servlets](https://www.baeldung.com/intro-to-servlets)
+- [An MVC Example with Servlets and JSP](https://www.baeldung.com/mvc-servlet-jsp)
+- [Handling Cookies and a Session in a Java Servlet](https://www.baeldung.com/java-servlet-cookies-session)
+- [Uploading Files with Servlets and JSP](https://www.baeldung.com/upload-file-servlet)
+- [Example of Downloading File in a Servlet](https://www.baeldung.com/servlet-download-file)
+- [Returning a JSON Response from a Servlet](https://www.baeldung.com/servlet-json-response)
+- [Java EE Servlet Exception Handling](https://www.baeldung.com/servlet-exceptions)
+- [Context and Servlet Initialization Parameters](https://www.baeldung.com/context-servlet-initialization-param)
+- [The Difference between getRequestURI and getPathInfo in HttpServletRequest](https://www.baeldung.com/http-servlet-request-requesturi-pathinfo)

javax-servlets/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.javax-servlets</groupId>
+    <artifactId>javax-servlets</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <name>javax-servlets</name>
+    <packaging>war</packaging>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    
+    <dependencies>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <!-- File Uploading -->
+        <dependency>
+            <groupId>commons-fileupload</groupId>
+            <artifactId>commons-fileupload</artifactId>
+            <version>${commons-fileupload.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+
+        <!-- Servlet -->
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>javax.servlet-api</artifactId>
+            <version>${javax.servlet-api.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet.jsp.jstl</groupId>
+            <artifactId>jstl-api</artifactId>
+            <version>${jstl.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet.jsp</groupId>
+            <artifactId>javax.servlet.jsp-api</artifactId>
+            <version>${javax.servlet.jsp-api.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>jstl</artifactId>
+            <version>${jstl.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${org.apache.httpcomponents.version}</version>
+            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>${spring-test.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+	
+    <properties>
+        <org.apache.httpcomponents.version>4.5.3</org.apache.httpcomponents.version>
+        <spring-test.version>5.0.5.RELEASE</spring-test.version>
+        <gson.version>2.8.2</gson.version>
+        <assertj.version>3.9.1</assertj.version>
+        <mockito.version>2.21.0</mockito.version>
+        <commons-fileupload.version>1.3.3</commons-fileupload.version>
+        <javax.servlet-api.version>4.0.1</javax.servlet-api.version>
+    </properties>
+</project>

javax-servlets/src/main/java/com/baeldung/Constants.java

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+package com.baeldung;
+
+public class Constants {
+
+  public static final String UPLOAD_DIRECTORY = "upload";
+  public static final String DEFAULT_FILENAME = "default.file";
+
+  public static final int MEMORY_THRESHOLD = 1024 * 1024 * 3;
+  public static final int MAX_FILE_SIZE = 1024 * 1024 * 40;
+  public static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50;
+}

javax-servlets/src/main/java/com/baeldung/controller/StudentServlet.java

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+package com.baeldung.controller;
+
+import com.baeldung.service.StudentService;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+@WebServlet(name = "StudentServlet", urlPatterns = "/student-record")
+public class StudentServlet extends HttpServlet {
+
+    private final StudentService studentService = new StudentService();
+
+    private void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String studentID = request.getParameter("id");
+        if (studentID != null) {
+            int id = Integer.parseInt(studentID);
+            studentService.getStudent(id)
+              .ifPresent(s -> request.setAttribute("studentRecord", s));
+        }
+
+        RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/student-record.jsp");
+        dispatcher.forward(request, response);
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        processRequest(request, response);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        processRequest(request, response);
+    }
+}

javax-servlets/src/main/java/com/baeldung/model/Employee.java

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+package com.baeldung.model;
+
+public class Employee {
+	
+	private int id;
+    private String name;
+    private String department;
+    private long salary;
+	
+    public Employee(int id, String name, String department, long salary) {
+		super();
+		this.id = id;
+		this.name = name;
+		this.department = department;
+		this.salary = salary;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + id;
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Employee other = (Employee) obj;
+		if (id != other.id)
+			return false;
+		return true;
+	}
+
+	public int getId() {
+		return id;
+	}
+	
+    public void setId(int id) {
+		this.id = id;
+	}
+	
+    public String getName() {
+		return name;
+	}
+	
+    public void setName(String name) {
+		this.name = name;
+	}
+	
+    public String getDepartment() {
+		return department;
+	}
+	
+    public void setDepartment(String department) {
+		this.department = department;
+	}
+	
+    public long getSalary() {
+		return salary;
+	}
+	
+    public void setSalary(long salary) {
+		this.salary = salary;
+	}
+	
+}

javax-servlets/src/main/java/com/baeldung/model/Student.java

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+package com.baeldung.model;
+
+public class Student {
+
+    private int id;
+    private String firstName;
+    private String lastName;
+
+    public Student(int id, String firstName, String lastName) {
+        super();
+        this.id = id;
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+}

javax-servlets/src/main/java/com/baeldung/service/StudentService.java

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+package com.baeldung.service;
+
+import com.baeldung.model.Student;
+
+import java.util.Optional;
+
+public class StudentService {
+
+    public Optional<Student> getStudent(int id) {
+        switch (id) {
+            case 1:
+                return Optional.of(new Student(1, "John", "Doe"));
+            case 2:
+                return Optional.of(new Student(2, "Jane", "Goodall"));
+            case 3:
+                return Optional.of(new Student(3, "Max", "Born"));
+            default:
+                return Optional.empty();
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/CookieReader.java

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+package com.baeldung.servlets;
+
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServletRequest;
+import java.util.Arrays;
+import java.util.Optional;
+
+/**
+ * Created by adam.
+ *
+ * Class which simplifies reading cookies from request.
+ */
+public class CookieReader {
+
+    private HttpServletRequest request;
+
+    /**
+     * The constructor.
+     *
+     * @param request request from which cookies will be read
+     */
+    public CookieReader(HttpServletRequest request) {
+        this.request = request;
+    }
+
+    /**
+     * Reads cookie by key from request.
+     *
+     * @param key the key of a cookie
+     * @return returns cookie value
+     */
+    public Optional<String> readCookie(String key) {
+        return Arrays.stream(request.getCookies())
+                 .filter(c -> key.equals(c.getName()))
+                 .map(Cookie::getValue)
+                 .findAny();
+    }
+
+}

javax-servlets/src/main/java/com/baeldung/servlets/DownloadServlet.java

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+package com.baeldung.servlets;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet("/download")
+public class DownloadServlet extends HttpServlet {
+    private final int ARBITARY_SIZE = 1048;
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
+        resp.setContentType("text/plain");
+        resp.setHeader("Content-disposition", "attachment; filename=sample.txt");
+
+        try (InputStream in = req.getServletContext().getResourceAsStream("/WEB-INF/sample.txt"); 
+            OutputStream out = resp.getOutputStream()) {
+            
+            byte[] buffer = new byte[ARBITARY_SIZE];
+            
+            int numBytesRead;
+            while ((numBytesRead = in.read(buffer)) > 0) {
+                out.write(buffer, 0, numBytesRead);
+            }
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/EmployeeServlet.java

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+package com.baeldung.servlets;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import com.baeldung.model.Employee;
+import com.google.gson.Gson;
+
+
+@WebServlet(name = "EmployeeServlet", urlPatterns = "/employeeServlet")
+public class EmployeeServlet extends HttpServlet {
+	
+	private Gson gson = new Gson();
+
+	@Override
+	public void doGet(HttpServletRequest request, HttpServletResponse response)
+		throws IOException {
+
+		Employee employee = new Employee(1, "Karan", "IT", 5000);
+		String employeeJsonString = this.gson.toJson(employee);
+
+		PrintWriter out = response.getWriter();
+		response.setContentType("application/json");
+		response.setCharacterEncoding("UTF-8");
+		out.print(employeeJsonString);
+		out.flush();   
+	}
+
+}

javax-servlets/src/main/java/com/baeldung/servlets/ErrorHandlerServlet.java

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+package com.baeldung.servlets;
+
+import javax.servlet.annotation.*;
+import javax.servlet.http.*;
+import java.io.*;
+import java.util.*;
+
+import static javax.servlet.RequestDispatcher.*;
+
+@WebServlet(urlPatterns = "/errorHandler")
+public class ErrorHandlerServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+            throws IOException {
+        resp.setContentType("text/html; charset=utf-8");
+        try (PrintWriter writer = resp.getWriter()) {
+            writer.write("<html><head><title>Error description</title></head><body>");
+            writer.write("<h2>Error description</h2>");
+            writer.write("<ul>");
+            Arrays.asList(ERROR_STATUS_CODE, ERROR_EXCEPTION_TYPE, ERROR_MESSAGE)
+                    .forEach(e ->
+                            writer.write("<li>" + e + ":" + req.getAttribute(e) + " </li>")
+                    );
+            writer.write("</ul>");
+            writer.write("</html></body>");
+        }
+
+        Exception exception = (Exception) req.getAttribute(ERROR_EXCEPTION);
+        if (IllegalArgumentException.class.isInstance(exception)) {
+            getServletContext().log("Error on an application argument", exception);
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/FormServlet.java

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+package com.baeldung.servlets;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+@WebServlet(name = "FormServlet", urlPatterns = "/calculateServlet")
+public class FormServlet extends HttpServlet {
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response)
+      throws IOException {
+
+        String height = request.getParameter("height");
+        String weight = request.getParameter("weight");
+
+        try {
+            double bmi = calculateBMI(Double.parseDouble(weight), Double.parseDouble(height));
+
+            request.setAttribute("bmi", bmi);
+            response.setHeader("Test", "Success");
+            response.setHeader("BMI", String.valueOf(bmi));
+
+            RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/index.jsp");
+            dispatcher.forward(request, response);
+        } catch (Exception e) {
+            response.sendRedirect("index.jsp");
+        }
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
+
+        // do something else here
+    }
+
+    private Double calculateBMI(Double weight, Double height) {
+        return weight / (height * height);
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/LoginServlet.java

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+package com.baeldung.servlets;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.*;
+import java.io.IOException;
+import java.util.Optional;
+
+/**
+ * Created by adam.
+ */
+@WebServlet(name = "LoginServlet", urlPatterns = "/login")
+public class LoginServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        CookieReader cookieReader = new CookieReader(request);
+        Optional<String> uiColor = cookieReader.readCookie("uiColor");
+        Optional<String> userName = cookieReader.readCookie("userName");
+
+        request.setAttribute("uiColor", uiColor.orElse("blue"));
+
+        if (!userName.isPresent()) {
+            RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/login.jsp");
+            dispatcher.forward(request, response);
+        } else {
+            response.sendRedirect("/welcome");
+        }
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        HttpSession session = request.getSession();
+        session.setAttribute("sampleKey", "Sample Value");
+
+        String uiColor = request.getParameter("color");
+        String userName = request.getParameter("name");
+
+        Cookie uiColorCookie = new Cookie("uiColor", uiColor);
+        response.addCookie(uiColorCookie);
+
+        Cookie userNameCookie = new Cookie("userName", userName);
+        response.addCookie(userNameCookie);
+
+        response.sendRedirect("/welcome");
+    }
+
+}

javax-servlets/src/main/java/com/baeldung/servlets/MultipartServlet.java

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+package com.baeldung.servlets;
+
+import com.baeldung.Constants;
+
+import javax.servlet.ServletException;
+import javax.servlet.annotation.MultipartConfig;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.Part;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+import static com.baeldung.Constants.UPLOAD_DIRECTORY;
+
+@WebServlet(
+    name = "MultiPartServlet",
+    urlPatterns = {"/multiPartServlet"}
+)
+@MultipartConfig(fileSizeThreshold = 1024 * 1024, maxFileSize = 1024 * 1024 * 5, maxRequestSize = 1024 * 1024 * 5 * 5)
+public class MultipartServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    private String getFileName(Part part) {
+        for (String content : part.getHeader("content-disposition").split(";")) {
+            if (content.trim().startsWith("filename"))
+                return content.substring(content.indexOf("=") + 2, content.length() - 1);
+        }
+        return Constants.DEFAULT_FILENAME;
+    }
+
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY;
+        File uploadDir = new File(uploadPath);
+        if (!uploadDir.exists())
+            uploadDir.mkdir();
+
+        try {
+            String fileName = "";
+            for (Part part : request.getParts()) {
+                fileName = getFileName(part);
+                part.write(uploadPath + File.separator + fileName);
+            }
+            request.setAttribute("message", "File " + fileName + " has uploaded successfully!");
+        } catch (FileNotFoundException fne) {
+            request.setAttribute("message", "There was an error: " + fne.getMessage());
+        }
+        getServletContext().getRequestDispatcher("/result.jsp").forward(request, response);
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/MyHttpServlet.java

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+package com.baeldung.servlets;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name = "MyHttpServlet", urlPatterns = "/servlet-mapping")
+public class MyHttpServlet extends HttpServlet {
+
+    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        PrintWriter writer = response.getWriter();
+        writer.println(request.getParameter("function"));
+        if ("getContextPath".equals(request.getParameter("function"))) {
+            writer.println(request.getContextPath());
+        } else if ("getLocalAddr".equals(request.getParameter("function"))) {
+            writer.println(request.getLocalAddr());
+        } else if ("getLocalName".equals(request.getParameter("function"))) {
+            writer.println(request.getLocalName());
+        } else if ("getLocalAPort".equals(request.getParameter("function"))) {
+            writer.println(request.getLocalPort());
+        } else if ("getMethod".equals(request.getParameter("function"))) {
+            writer.println(request.getMethod());
+        } else if ("getParameterNames".equals(request.getParameter("function"))) {
+            writer.println(request.getParameterNames());
+        } else if ("getPathInfo".equals(request.getParameter("function"))) {
+            writer.println(request.getPathInfo());
+        } else if ("getProtocol".equals(request.getParameter("function"))) {
+            writer.println(request.getProtocol());
+        } else if ("getQueryString".equals(request.getParameter("function"))) {
+            writer.println(request.getQueryString());
+        } else if ("getRequestedSessionId".equals(request.getParameter("function"))) {
+            writer.println(request.getRequestedSessionId());
+        } else if ("getRequestURI".equals(request.getParameter("function"))) {
+            writer.println(request.getRequestURI());
+        } else if ("getRequestURL".equals(request.getParameter("function"))) {
+            writer.println(request.getRequestURL());
+        } else if ("getScheme".equals(request.getParameter("function"))) {
+            writer.println(request.getScheme());
+        } else if ("getServerName".equals(request.getParameter("function"))) {
+            writer.println(request.getServerName());
+        } else if ("getServerPort".equals(request.getParameter("function"))) {
+            writer.println(request.getServerPort());
+        } else if ("getServletPath".equals(request.getParameter("function"))) {
+            writer.println(request.getServletPath());
+        } else {
+            writer.println("INVALID FUNCTION");
+        }
+        writer.flush();
+    }
+    
+}
+
+

javax-servlets/src/main/java/com/baeldung/servlets/RandomErrorServlet.java

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+package com.baeldung.servlets;
+
+import javax.servlet.annotation.*;
+import javax.servlet.http.*;
+
+@WebServlet(urlPatterns = "/randomError")
+public class RandomErrorServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, final HttpServletResponse resp) {
+        throw new IllegalStateException("Random error");
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/UploadServlet.java

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+package com.baeldung.servlets;
+
+import javax.servlet.annotation.WebServlet;
+import org.apache.commons.fileupload.FileItem;
+import org.apache.commons.fileupload.disk.DiskFileItemFactory;
+import org.apache.commons.fileupload.servlet.ServletFileUpload;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+import static com.baeldung.Constants.*;
+
+@WebServlet(
+    name = "UploadServlet",
+    urlPatterns = {"/uploadFile"}
+)
+public class UploadServlet extends HttpServlet {
+
+    private static final long serialVersionUID = 1L;
+
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+        if (ServletFileUpload.isMultipartContent(request)) {
+
+            DiskFileItemFactory factory = new DiskFileItemFactory();
+            factory.setSizeThreshold(MEMORY_THRESHOLD);
+            factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
+
+            ServletFileUpload upload = new ServletFileUpload(factory);
+            upload.setFileSizeMax(MAX_FILE_SIZE);
+            upload.setSizeMax(MAX_REQUEST_SIZE);
+            String uploadPath = getServletContext().getRealPath("") + File.separator + UPLOAD_DIRECTORY;
+            File uploadDir = new File(uploadPath);
+            if (!uploadDir.exists()) {
+                uploadDir.mkdir();
+            }
+
+            try {
+                List<FileItem> formItems = upload.parseRequest(request);
+
+                if (formItems != null && formItems.size() > 0) {
+                    for (FileItem item : formItems) {
+                        if (!item.isFormField()) {
+                            String fileName = new File(item.getName()).getName();
+                            String filePath = uploadPath + File.separator + fileName;
+                            File storeFile = new File(filePath);
+                            item.write(storeFile);
+                            request.setAttribute("message", "File " + fileName + " has uploaded successfully!");
+                        }
+                    }
+                }
+            } catch (Exception ex) {
+                request.setAttribute("message", "There was an error: " + ex.getMessage());
+            }
+            getServletContext().getRequestDispatcher("/result.jsp").forward(request, response);
+        }
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/UploadWelcomeServlet.java

@@ -0,0 +1,18 @@
+package com.baeldung.servlets;
+
+import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name = "UploadWelcomeServlet", urlPatterns = "/uploadwelcome")
+public class UploadWelcomeServlet extends HttpServlet {
+
+  @Override
+  protected void doGet(HttpServletRequest request, HttpServletResponse response)
+      throws ServletException, IOException {
+    request.getRequestDispatcher("/upload.jsp").forward(request, response);
+  }
+}

javax-servlets/src/main/java/com/baeldung/servlets/UserServlet.java

@@ -0,0 +1,49 @@
+package com.baeldung.servlets;
+
+import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebInitParam;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+@WebServlet(name = "UserServlet", urlPatterns = {"/userServlet"}, initParams={
+    @WebInitParam(name="name", value="Not provided"), 
+    @WebInitParam(name="email", value="Not provided")})
+public class UserServlet extends HttpServlet {
+    
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+    }
+    
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+        processRequest(request, response);
+        forwardRequest(request, response, "/WEB-INF/jsp/result.jsp");
+    }
+    
+    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException {
+        request.setAttribute("name", getRequestParameter(request, "name"));
+        request.setAttribute("email", getRequestParameter(request, "email"));
+        request.setAttribute("province", getContextParameter("province"));
+        request.setAttribute("country", getContextParameter("country"));
+    }
+    
+    protected String getRequestParameter(HttpServletRequest request, String name) {
+        String param = request.getParameter(name);
+        return !param.isEmpty() ? param : getInitParameter(name);
+    }
+    
+    protected String getContextParameter(String name) {
+        return getServletContext().getInitParameter(name);
+    }
+    
+    protected void forwardRequest(HttpServletRequest request, HttpServletResponse response, String path) 
+            throws ServletException, IOException {
+        request.getRequestDispatcher(path).forward(request, response);
+    }
+}

javax-servlets/src/main/java/com/baeldung/servlets/WelcomeServlet.java

@@ -0,0 +1,47 @@
+package com.baeldung.servlets;
+
+import javax.servlet.RequestDispatcher;
+import javax.servlet.ServletException;
+import javax.servlet.annotation.WebServlet;
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.Optional;
+
+/**
+ * Created by adam.
+ */
+@WebServlet(name = "WelcomeServlet", urlPatterns = "/welcome")
+public class WelcomeServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        CookieReader cookieReader = new CookieReader(request);
+        Optional<String> uiColor = cookieReader.readCookie("uiColor");
+        Optional<String> userName = cookieReader.readCookie("userName");
+
+        if (!userName.isPresent()) {
+            response.sendRedirect("/login");
+        } else {
+            request.setAttribute("uiColor", uiColor.orElse("blue"));
+            request.setAttribute("userName", userName.get());
+            request.setAttribute("sessionAttribute", request.getSession()
+                .getAttribute("sampleKey"));
+
+            RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp");
+            dispatcher.forward(request, response);
+        }
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        Cookie userNameCookieRemove = new Cookie("userName", "");
+        userNameCookieRemove.setMaxAge(0);
+        response.addCookie(userNameCookieRemove);
+
+        response.sendRedirect("/login");
+    }
+
+}

javax-servlets/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

javax-servlets/src/main/webapp/WEB-INF/jsp/index.jsp

@@ -0,0 +1,26 @@
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+    <title>Calculate BMI</title>
+</head>
+<body>
+
+<form name="bmiForm" action="calculateServlet" method="POST">
+
+    <table>
+        <tr>
+            <td>Your Weight (kg) :</td>
+            <td><input type="text" name="weight"/></td>
+        </tr>
+        <tr>
+            <td>Your Height (m) :</td>
+            <td><input type="text" name="height"/></td>
+        </tr>
+        <th><input type="submit" value="Submit" name="find"/></th>
+        <th><input type="reset" value="Reset" name="reset" /></th>
+    </table>
+    <h2>${bmi}</h2>
+</form>
+
+</body>
+</html>

javax-servlets/src/main/webapp/WEB-INF/jsp/login.jsp

@@ -0,0 +1,17 @@
+<%@ page contentType="text/html;charset=UTF-8"%>
+<html>
+<head>
+    <title>Hello New User:</title>
+</head>
+<body style="background: ${uiColor}">
+    <form name="userForm" action="login" method="POST">
+        <label>Your Name:</label>
+        <input type="text" name="name"/>
+
+        <label>UI Color:</label>
+        <input type="text" name="color"/>
+
+        <button type="submit">Confirm</button>
+    </form>
+</body>
+</html>

javax-servlets/src/main/webapp/WEB-INF/jsp/result.jsp

@@ -0,0 +1,16 @@
+<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
+<%@ page contentType="text/html" pageEncoding="UTF-8"%>
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+        <title>User Data</title>
+    </head>
+    <body>
+        <h2>User Information</h2>
+        <p><strong>Name:</strong> ${name}</p>
+        <p><strong>Email:</strong> ${email}</p>
+        <p><strong>Province:</strong> ${province}</p>
+        <p><strong>Country:</strong> ${country}</p>
+    </body>
+</html>

javax-servlets/src/main/webapp/WEB-INF/jsp/student-record.jsp

@@ -0,0 +1,36 @@
+<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
+    pageEncoding="ISO-8859-1"%>
+
+<%@ page import="com.baeldung.model.Student"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
+<title>Student Record</title>
+</head>
+<body>
+    <%
+        if (request.getAttribute("studentRecord") != null) {
+            Student student = (Student) request.getAttribute("studentRecord");
+    %>
+
+    <h1>Student Record</h1>
+    <div>
+        ID:
+        <%=student.getId()%></div>
+    <div>
+        First Name:
+        <%=student.getFirstName()%></div>
+    <div>
+        Last Name:
+        <%=student.getLastName()%></div>
+
+    <%
+        } else {
+    %>
+    <h1>No student record found.</h1>
+    <%
+        }
+    %>
+</body>
+</html>

javax-servlets/src/main/webapp/WEB-INF/jsp/welcome.jsp

@@ -0,0 +1,13 @@
+<%@ page contentType="text/html;charset=UTF-8"%>
+<html>
+<head>
+    <title>Hello Known User:</title>
+</head>
+<body style="background: ${uiColor}">
+    <form action="welcome" method="POST">
+        <label>Your name: ${userName}</label>
+        <label>Session param: ${sessionAttribute}</label>
+        <button type="submit">Logout</button>
+    </form>
+</body>
+</html>

javax-servlets/src/main/webapp/WEB-INF/web.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://java.sun.com/xml/ns/javaee"
+         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
+    http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">
+    <context-param>
+        <param-name>province</param-name>
+        <param-value>Mendoza</param-value>
+    </context-param>
+    <context-param>
+        <param-name>country</param-name>
+        <param-value>Argentina</param-value>
+    </context-param>
+    <error-page>
+        <error-code>404</error-code>
+        <location>/error-404.html</location> <!-- /src/main/webapp/error-404.html-->
+    </error-page>
+
+    <error-page>
+        <exception-type>java.lang.Exception</exception-type>
+        <location>/errorHandler</location>
+    </error-page>
+</web-app>

javax-servlets/src/main/webapp/error-404.html

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>Error page</title>
+</head>
+<body>
+
+<h2>Error: Page not found</h2>
+
+<a href="./">Go back home</a>
+
+</body>
+</html>

javax-servlets/src/main/webapp/result.jsp

@@ -0,0 +1,13 @@
+<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <title>Upload Result</title>
+</head>
+
+<body>
+    <h2>${message}</h2>
+</body>
+</html>

javax-servlets/src/main/webapp/sample.txt

@@ -0,0 +1 @@
+nice simple text file

javax-servlets/src/main/webapp/upload.jsp

@@ -0,0 +1,23 @@
+<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    <title>File Upload Demo</title>
+</head>
+
+<body>
+    <div>Apache FileUpload</div>
+    <form method="post" action="uploadFile" enctype="multipart/form-data">
+        Choose a file: <input type="file" name="uploadFile"/><input type="submit" value="Upload"/>
+    </form>
+
+    </br>
+
+    <div>Servlet Multipart</div>
+    <form method="post" action="multiPartServlet" enctype="multipart/form-data">
+        Choose a file: <input type="file" name="multiPartServlet"/><input type="submit" value="Upload"/>
+    </form>
+</body>
+</html>

javax-servlets/src/main/webapp/user.jsp

@@ -0,0 +1,19 @@
+<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
+<%@ page contentType="text/html" pageEncoding="UTF-8"%>
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Context and Servlet Initialization  Parameters</title>
+        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+    </head>
+    <body>
+        <h2>Please fill the form below:</h2>
+        <form action="${pageContext.request.contextPath}/userServlet" method="post">
+            <label for="name"><strong>Name:</strong></label>
+            <input type="text" name="name" id="name">
+            <label for="email"><strong>Email:</strong></label>
+            <input type="text" name="email" id="email">
+            <input type="submit" value="Send">
+        </form>
+    </body>
+</html>

javax-servlets/src/test/java/com/baeldung/servlets/EmployeeServletIntegrationTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.servlets;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.when;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import com.baeldung.model.Employee;
+import com.google.gson.Gson;
+
+
+@RunWith(MockitoJUnitRunner.class)
+public class EmployeeServletIntegrationTest {
+
+	@Mock
+	HttpServletRequest httpServletRequest;
+
+	@Mock
+	HttpServletResponse httpServletResponse;
+
+	Employee employee;
+
+	@Test
+	public void whenPostRequestToEmployeeServlet_thenEmployeeReturnedAsJson() throws Exception {
+
+		//Given
+		int id = 1;
+		String name = "Karan Khanna";
+		String department = "IT";
+		long salary = 5000;
+		employee = new Employee(id, name, department, salary);
+
+		StringWriter sw = new StringWriter();
+		PrintWriter pw = new PrintWriter(sw);
+		when(httpServletResponse.getWriter()).thenReturn(pw);
+
+		EmployeeServlet employeeServlet = new EmployeeServlet();
+		employeeServlet.doGet(httpServletRequest, httpServletResponse);
+
+		String employeeJsonString = sw.getBuffer().toString().trim();
+		Employee fetchedEmployee = new Gson().fromJson(employeeJsonString, Employee.class);
+		assertEquals(fetchedEmployee, employee);
+	}
+
+}

javax-servlets/src/test/java/com/baeldung/test/FormServletLiveTest.java

@@ -0,0 +1,34 @@
+package com.baeldung.servlets;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.message.BasicNameValuePair;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class FormServletLiveTest {
+
+    @Test
+    public void whenPostRequestUsingHttpClient_thenCorrect() throws Exception {
+
+        HttpClient client = HttpClientBuilder.create().build();
+        HttpPost method = new HttpPost("http://localhost:8080/calculateServlet");
+
+        List<BasicNameValuePair> nvps = new ArrayList<>();
+        nvps.add(new BasicNameValuePair("height", String.valueOf(2)));
+        nvps.add(new BasicNameValuePair("weight", String.valueOf(80)));
+
+        method.setEntity(new UrlEncodedFormEntity(nvps));
+        HttpResponse httpResponse = client.execute(method);
+
+        assertEquals("Success", httpResponse.getHeaders("Test")[0].getValue());
+        assertEquals("20.0", httpResponse.getHeaders("BMI")[0].getValue());
+    }
+}

javax-servlets/src/test/java/com/baeldung/test/UserServletUnitTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.servlets;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import static org.mockito.Mockito.atLeast;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class UserServletUnitTest {
+    
+    private static HttpServletRequest request;
+    private static HttpServletResponse response;
+    
+    
+    @BeforeClass
+    public static void setUpHttpServletRequestMockInstance() {
+        request = mock(HttpServletRequest.class); 
+    }
+    
+    @BeforeClass
+    public static void setUpHttpServletResponsetMockInstance() {
+        response = mock(HttpServletResponse.class); 
+    }
+    
+    @Test
+    public void givenHttpServletRequestMockInstance_whenCalledgetParameter_thenCalledAtLeastOnce() {
+        request.getParameter("name");
+        verify(request, atLeast(1)).getParameter("name");
+    }
+    
+    @Test
+    public void givenHttpServletRequestMockInstance_whenCalledgetParameter_thenOneAssertion() {  
+        when(request.getParameter("name")).thenReturn("username");
+        assertThat(request.getParameter("name")).isEqualTo("username");
+    }
+    
+    @Test
+    public void givenHttpServletResponseMockInstance_whenCalledgetContentType_thenCalledAtLeastOnce() {
+        response.getContentType();
+        verify(response, atLeast(1)).getContentType();
+    }
+    
+    @Test
+    public void givenHttpServletResponseMockInstance_whenCalledgetContentType_thenOneAssertion() {
+        when(response.getContentType()).thenReturn("text/html");
+        assertThat(response.getContentType()).isEqualTo("text/html");
+    }
+}