BAEL-1914 (#4713)

* Server Sent Events example using Spring Webflux and React

* spring security custom AuthenticationFailureHandler

* refactor

* moved SSE to branch

* BAEL-1914

* remove pom properties

spring-boot-security/src/main/java/com/baeldung/springbootsecurity/form_login/SpringBootSecurityApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung.springbootsecurity.form_login;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication(scanBasePackages = "com.baeldung.springbootsecurity.form_login")
+public class SpringBootSecurityApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringBootSecurityApplication.class, args);
+    }
+}

spring-boot-security/src/main/java/com/baeldung/springbootsecurity/form_login/configuration/SecurityConfiguration.java

@@ -0,0 +1,67 @@
+package com.baeldung.springbootsecurity.form_login.configuration;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.web.authentication.AuthenticationFailureHandler;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.Calendar;
+import java.util.HashMap;
+import java.util.Map;
+
+@Configuration
+@EnableWebSecurity
+public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
+
+    @Override
+    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+        auth
+                .inMemoryAuthentication()
+                .withUser("baeldung")
+                .password("baeldung")
+                .roles("USER");
+    }
+
+    @Override
+    protected void configure(HttpSecurity http) throws Exception {
+        http
+                .authorizeRequests()
+                .anyRequest()
+                .authenticated()
+                .and()
+                .formLogin()
+                .failureHandler(customAuthenticationFailureHandler());
+    }
+
+    @Bean
+    public AuthenticationFailureHandler customAuthenticationFailureHandler() {
+        return new CustomAuthenticationFailureHandler();
+    }
+
+    /**
+     * Custom AuthenticationFailureHandler
+     */
+    public class CustomAuthenticationFailureHandler implements AuthenticationFailureHandler {
+        private final ObjectMapper objectMapper = new ObjectMapper();
+
+        @Override
+        public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException {
+            response.setStatus(HttpStatus.UNAUTHORIZED.value());
+            Map<String, Object> data = new HashMap<>();
+            data.put("timestamp", Calendar.getInstance().getTime());
+            data.put("exception", exception.getMessage());
+
+            response.getOutputStream().println(objectMapper.writeValueAsString(data));
+        }
+    }
+}