BAEL-1533 Making a Spring MVC Form Remember Values

- add example code
- update pom dependency to spring boot starter 2.0.0.RC2
- update import in SpringApplicationException

spring-5/src/main/java/com/baeldung/execption/SpringExceptionApplication.java

@@ -1,14 +1,14 @@
-package com.baeldung.execption;
-
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.boot.autoconfigure.security.SecurityAutoConfiguration;
-import org.springframework.context.annotation.ComponentScan;
-
-@SpringBootApplication(exclude = SecurityAutoConfiguration.class)
-@ComponentScan(basePackages = { "com.baeldung.execption" })
-public class SpringExceptionApplication {
-    public static void main(String[] args) {
-        SpringApplication.run(SpringExceptionApplication.class, args);
-    }
+package com.baeldung.execption;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
+import org.springframework.context.annotation.ComponentScan;
+
+@SpringBootApplication(exclude = SecurityAutoConfiguration.class)
+@ComponentScan(basePackages = { "com.baeldung.execption" })
+public class SpringExceptionApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(SpringExceptionApplication.class, args);
+    }
 }

spring-5/src/main/java/com/baeldung/sessionattrs/Config.java

@@ -0,0 +1,44 @@
+package com.baeldung.sessionattrs;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+import org.springframework.core.Ordered;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+import org.thymeleaf.templatemode.TemplateMode;
+import org.thymeleaf.templateresolver.ClassLoaderTemplateResolver;
+import org.thymeleaf.templateresolver.ITemplateResolver;
+
+@EnableWebMvc
+@Configuration
+public class Config implements WebMvcConfigurer {
+
+    @Override
+    public void addViewControllers(ViewControllerRegistry registry) {
+        registry.addViewController("/").setViewName("index");
+        registry.setOrder(Ordered.HIGHEST_PRECEDENCE);
+    }
+
+    @Bean
+    @Scope(
+        value = WebApplicationContext.SCOPE_SESSION, 
+        proxyMode = ScopedProxyMode.TARGET_CLASS)
+    public TodoList todos() {
+        return new TodoList();
+    }
+
+    @Bean
+    public ITemplateResolver templateResolver() {
+        ClassLoaderTemplateResolver resolver 
+            = new ClassLoaderTemplateResolver();
+        resolver.setPrefix("templates/sessionattrs/");
+        resolver.setSuffix(".html");
+        resolver.setTemplateMode(TemplateMode.HTML);
+        resolver.setCharacterEncoding("UTF-8");
+        return resolver;
+    }
+}

spring-5/src/main/java/com/baeldung/sessionattrs/SessionAttrsApplication.java

@@ -0,0 +1,16 @@
+package com.baeldung.sessionattrs;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
+import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
+
+@SpringBootApplication(
+        exclude = {SecurityAutoConfiguration.class, 
+                DataSourceAutoConfiguration.class})
+public class SessionAttrsApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SessionAttrsApplication.class, args);
+    }
+}

spring-5/src/main/java/com/baeldung/sessionattrs/TodoControllerWithScopedProxy.java

@@ -0,0 +1,45 @@
+package com.baeldung.sessionattrs;
+
+import java.time.LocalDateTime;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+@RequestMapping("/scopedproxy")
+public class TodoControllerWithScopedProxy {
+
+    private TodoList todos;
+
+    public TodoControllerWithScopedProxy(TodoList todos) {
+        this.todos = todos;
+    }
+
+    @GetMapping("/form")
+    public String showForm(Model model) {
+        if (!todos.isEmpty()) {
+            model.addAttribute("todo", todos.peekLast());
+        } else {
+            model.addAttribute("todo", new TodoItem());
+        }
+
+        return "scopedproxyform";
+    }
+
+    @PostMapping("/form")
+    public String create(@ModelAttribute TodoItem todo) {
+        todo.setCreateDate(LocalDateTime.now());
+        todos.add(todo);
+        return "redirect:/scopedproxy/todos.html";
+    }
+
+    @GetMapping("/todos.html")
+    public String list(Model model) {
+        model.addAttribute("todos", todos);
+        return "scopedproxytodos";
+    }
+}

spring-5/src/main/java/com/baeldung/sessionattrs/TodoControllerWithSessionAttributes.java

@@ -0,0 +1,55 @@
+package com.baeldung.sessionattrs;
+
+import java.time.LocalDateTime;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.SessionAttributes;
+import org.springframework.web.servlet.mvc.support.RedirectAttributes;
+import org.springframework.web.servlet.view.RedirectView;
+
+@Controller
+@RequestMapping("/sessionattributes")
+@SessionAttributes("todos")
+public class TodoControllerWithSessionAttributes {
+
+    @GetMapping("/form")
+    public String showForm(
+            Model model,
+            @ModelAttribute("todos") TodoList todos) {
+        if (!todos.isEmpty()) {
+            model.addAttribute("todo", todos.peekLast());
+        } else {
+            model.addAttribute("todo", new TodoItem());
+        }
+        return "sessionattributesform";
+    }
+
+    @PostMapping("/form")
+    public RedirectView create(
+            @ModelAttribute TodoItem todo, 
+            @ModelAttribute("todos") TodoList todos, 
+            RedirectAttributes attributes) {
+        todo.setCreateDate(LocalDateTime.now());
+        todos.add(todo);
+        attributes.addFlashAttribute("todos", todos);
+        return new RedirectView("/sessionattributes/todos.html");
+    }
+
+    @GetMapping("/todos.html")
+    public String list(
+            Model model, 
+            @ModelAttribute("todos") TodoList todos) {
+        model.addAttribute("todos", todos);
+        return "sessionattributestodos";
+    }
+
+    @ModelAttribute("todos")
+    public TodoList todos() {
+        return new TodoList();
+    }
+}

spring-5/src/main/java/com/baeldung/sessionattrs/TodoItem.java

@@ -0,0 +1,39 @@
+package com.baeldung.sessionattrs;
+
+import java.time.LocalDateTime;
+
+public class TodoItem {
+
+    private String description;
+    private LocalDateTime createDate;
+
+    public TodoItem(String description, LocalDateTime createDate) {
+        this.description = description;
+        this.createDate = createDate;
+    }
+
+    public TodoItem() {
+        // default no arg constructor
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public LocalDateTime getCreateDate() {
+        return createDate;
+    }
+
+    public void setCreateDate(LocalDateTime createDate) {
+        this.createDate = createDate;
+    }
+
+    @Override
+    public String toString() {
+        return "TodoItem [description=" + description + ", createDate=" + createDate + "]";
+    }
+}

spring-5/src/main/java/com/baeldung/sessionattrs/TodoList.java

@@ -0,0 +1,8 @@
+package com.baeldung.sessionattrs;
+
+import java.util.ArrayDeque;
+
+@SuppressWarnings("serial")
+public class TodoList extends ArrayDeque<TodoItem>{
+
+}