Added example for spring boot exception handling

spring-boot-rest/README.md

@@ -1,3 +1,4 @@
 Module for the articles that are part of the Spring REST E-book:
 
 1. [Bootstrap a Web Application with Spring 5](https://www.baeldung.com/bootstraping-a-web-application-with-spring-and-java-based-configuration)
+2. [Error Handling for REST with Spring](http://www.baeldung.com/exception-handling-for-rest-with-spring)

spring-boot-rest/pom.xml

@@ -20,12 +20,22 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-xml</artifactId>
+        </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>net.sourceforge.htmlunit</groupId>
+            <artifactId>htmlunit</artifactId>
+            <version>${htmlunit.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -39,5 +49,6 @@
 
     <properties>
         <start-class>com.baeldung.SpringBootRestApplication</start-class>
+        <htmlunit.version>2.32</htmlunit.version>
     </properties>
 </project>

spring-boot-rest/src/main/java/com/baeldung/errorhandling/boot/ErrorHandlingBootApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.errorhandling.boot;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication
+@PropertySource("errorhandling-application.properties")
+public class ErrorHandlingBootApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ErrorHandlingBootApplication.class, args);
+    }
+
+}

spring-boot-rest/src/main/java/com/baeldung/errorhandling/boot/configurations/MyCustomErrorAttributes.java

@@ -0,0 +1,23 @@
+package com.baeldung.errorhandling.boot.configurations;
+
+import java.util.Map;
+
+import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
+import org.springframework.stereotype.Component;
+import org.springframework.web.context.request.WebRequest;
+
+@Component
+public class MyCustomErrorAttributes extends DefaultErrorAttributes {
+
+    @Override
+    public Map<String, Object> getErrorAttributes(WebRequest webRequest, boolean includeStackTrace) {
+        Map<String, Object> errorAttributes = super.getErrorAttributes(webRequest, includeStackTrace);
+        errorAttributes.put("locale", webRequest.getLocale()
+            .toString());
+        errorAttributes.remove("error");
+        errorAttributes.put("cause", errorAttributes.get("message"));
+        errorAttributes.remove("message");
+        errorAttributes.put("status", String.valueOf(errorAttributes.get("status")));
+        return errorAttributes;
+    }
+}

spring-boot-rest/src/main/java/com/baeldung/errorhandling/boot/configurations/MyErrorController.java

@@ -0,0 +1,31 @@
+package com.baeldung.errorhandling.boot.configurations;
+
+import java.util.Map;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.boot.autoconfigure.web.ErrorProperties;
+import org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController;
+import org.springframework.boot.web.servlet.error.ErrorAttributes;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Component;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Component
+public class MyErrorController extends BasicErrorController {
+
+    public MyErrorController(ErrorAttributes errorAttributes) {
+        super(errorAttributes, new ErrorProperties());
+    }
+
+    @RequestMapping(produces = MediaType.APPLICATION_XML_VALUE)
+    public ResponseEntity<Map<String, Object>> xmlError(HttpServletRequest request) {
+        Map<String, Object> body = getErrorAttributes(request, isIncludeStackTrace(request, MediaType.APPLICATION_XML));
+        body.put("xmlkey", "the XML response is different!");
+        HttpStatus status = getStatus(request);
+        return new ResponseEntity<>(body, status);
+    }
+
+}

spring-boot-rest/src/main/java/com/baeldung/errorhandling/boot/web/FaultyRestController.java

@@ -0,0 +1,15 @@
+package com.baeldung.errorhandling.boot.web;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class FaultyRestController {
+    
+    @GetMapping("/exception")
+    public ResponseEntity<Void> requestWithException() {
+        throw new NullPointerException("Error in the faulty controller!");
+    }
+
+}

spring-boot-rest/src/main/java/com/baeldung/web/SpringBootRestApplication.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.web;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;

spring-boot-rest/src/main/resources/errorhandling-application.properties

@@ -0,0 +1,3 @@
+
+#server.error.whitelabel.enabled=false
+#server.error.include-stacktrace=always

spring-boot-rest/src/test/java/com/baeldung/errorhandling/boot/ErrorHandlingLiveTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.errorhandling.boot;
+
+import static io.restassured.RestAssured.given;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.hamcrest.Matchers.hasKey;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.isA;
+import static org.hamcrest.Matchers.not;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+
+import com.gargoylesoftware.htmlunit.WebClient;
+import com.gargoylesoftware.htmlunit.html.HtmlPage;
+
+public class ErrorHandlingLiveTest {
+
+    private static final String BASE_URL = "http://localhost:8080";
+    private static final String EXCEPTION_ENDPOINT = "/exception";
+
+    private static final String ERROR_RESPONSE_KEY_PATH = "error";
+    private static final String XML_RESPONSE_KEY_PATH = "xmlkey";
+    private static final String LOCALE_RESPONSE_KEY_PATH = "locale";
+    private static final String CAUSE_RESPONSE_KEY_PATH = "cause";
+    private static final String RESPONSE_XML_ROOT = "Map";
+    private static final String XML_RESPONSE_KEY_XML_PATH = RESPONSE_XML_ROOT + "." + XML_RESPONSE_KEY_PATH;
+    private static final String LOCALE_RESPONSE_KEY_XML_PATH = RESPONSE_XML_ROOT + "." + LOCALE_RESPONSE_KEY_PATH;
+    private static final String CAUSE_RESPONSE_KEY_XML_PATH = RESPONSE_XML_ROOT + "." + CAUSE_RESPONSE_KEY_PATH;
+    private static final String CAUSE_RESPONSE_VALUE = "Error in the faulty controller!";
+    private static final String XML_RESPONSE_VALUE = "the XML response is different!";
+
+    @Test
+    public void whenRequestingFaultyEndpointAsJson_thenReceiveDefaultResponseWithConfiguredAttrs() {
+        given().header(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE)
+            .get(EXCEPTION_ENDPOINT)
+            .then()
+            .body("$", hasKey(LOCALE_RESPONSE_KEY_PATH))
+            .body(CAUSE_RESPONSE_KEY_PATH, is(CAUSE_RESPONSE_VALUE))
+            .body("$", not(hasKey(ERROR_RESPONSE_KEY_PATH)))
+            .body("$", not(hasKey(XML_RESPONSE_KEY_PATH)));
+    }
+
+    @Test
+    public void whenRequestingFaultyEndpointAsXml_thenReceiveXmlResponseWithConfiguredAttrs() {
+        given().header(HttpHeaders.ACCEPT, MediaType.APPLICATION_XML_VALUE)
+            .get(EXCEPTION_ENDPOINT)
+            .then()
+            .body(LOCALE_RESPONSE_KEY_XML_PATH, isA(String.class))
+            .body(CAUSE_RESPONSE_KEY_XML_PATH, is(CAUSE_RESPONSE_VALUE))
+            .body(RESPONSE_XML_ROOT, not(hasKey(ERROR_RESPONSE_KEY_PATH)))
+            .body(XML_RESPONSE_KEY_XML_PATH, is(XML_RESPONSE_VALUE));
+    }
+
+    @Test
+    public void whenRequestingFaultyEndpointAsHtml_thenReceiveWhitelabelPageResponse() throws Exception {
+        try (WebClient webClient = new WebClient()) {
+            webClient.getOptions()
+                .setThrowExceptionOnFailingStatusCode(false);
+            HtmlPage page = webClient.getPage(BASE_URL + EXCEPTION_ENDPOINT);
+            assertThat(page.getBody()
+                .asText()).contains("Whitelabel Error Page");
+        }
+    }
+}

spring-boot-rest/src/test/java/com/baeldung/web/SpringContextIntegrationTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.spring.boot.rest;
+package com.baeldung.web;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;

spring-rest-full/README.md

@@ -18,7 +18,6 @@ The "Learn Spring Security" Classes: http://github.learnspringsecurity.com
 - [Metrics for your Spring REST API](http://www.baeldung.com/spring-rest-api-metrics)
 - [Bootstrap a Web Application with Spring 4](http://www.baeldung.com/bootstraping-a-web-application-with-spring-and-java-based-configuration)
 - [Build a REST API with Spring and Java Config](http://www.baeldung.com/building-a-restful-web-service-with-spring-and-java-based-configuration)
-- [Error Handling for REST with Spring](http://www.baeldung.com/exception-handling-for-rest-with-spring)
 - [Spring Security Expressions - hasRole Example](https://www.baeldung.com/spring-security-expressions-basic)