BAEL-8372: Add samples for content negotiation in error handling. (#18410)

Co-authored-by: Ralf Ueberfuhr <[email protected]>

Author: ueberfuhr

spring-boot-rest/pom.xml

@@ -119,6 +119,7 @@
         <dependency>
             <groupId>net.sourceforge.htmlunit</groupId>
             <artifactId>htmlunit</artifactId>
+            <version>${htmlunit.version}</version>
             <scope>test</scope>
             <exclusions>
                 <exclusion>
@@ -174,6 +175,11 @@
         <modelmapper.version>3.2.0</modelmapper.version>
         <rest-assured.version>5.5.0</rest-assured.version>
         <jaxb-runtime.version>4.0.1</jaxb-runtime.version>
-        <spring-oxm.version>6.1.4</spring-oxm.version>
+        <spring-oxm.version>6.2.3</spring-oxm.version>
+        <spring-boot.version>3.4.3</spring-boot.version>
+        <!-- https://github.com/qos-ch/logback/issues/853 -->
+        <logback.version>1.5.17</logback.version>
+        <!-- not managed by Spring anymore -->
+        <htmlunit.version>2.70.0</htmlunit.version>
     </properties>
 </project>

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

@@ -0,0 +1,38 @@
+package com.baeldung.web.error;
+
+import com.baeldung.web.exception.CustomException3;
+import com.baeldung.web.exception.CustomException4;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.HttpStatusCode;
+import org.springframework.http.MediaType;
+import org.springframework.http.ProblemDetail;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class MyGlobalExceptionHandler {
+
+    // simple example for global exception handling
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler(CustomException3.class)
+    public void handleCustomException3() {
+        //
+    }
+
+    // content negotiation
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler(produces = MediaType.APPLICATION_JSON_VALUE)
+    public ProblemDetail handleCustomException4Json(CustomException4 ex) {
+        String message = "custom exception 4: " + ex.getMessage();
+        return ProblemDetail
+                .forStatusAndDetail(HttpStatusCode.valueOf(HttpStatus.BAD_REQUEST.value()), message);
+    }
+
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    @ExceptionHandler(produces = MediaType.TEXT_PLAIN_VALUE)
+    public String handleCustomException4Text(CustomException4 ex) {
+        return "custom exception 4: " + ex.getMessage();
+    }
+
+}

spring-boot-rest/src/main/java/com/baeldung/web/exception/CustomException3.java

@@ -0,0 +1,10 @@
+package com.baeldung.web.exception;
+
+import java.io.Serial;
+
+public class CustomException3 extends RuntimeException {
+
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+}

spring-boot-rest/src/main/java/com/baeldung/web/exception/CustomException4.java

@@ -0,0 +1,13 @@
+package com.baeldung.web.exception;
+
+import java.io.Serial;
+
+public class CustomException4 extends RuntimeException {
+
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    public CustomException4(String message) {
+        super(message);
+    }
+}

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

@@ -0,0 +1,69 @@
+package com.baeldung.web;
+
+import com.baeldung.persistence.service.IFooService;
+import com.baeldung.web.controller.FooController;
+import com.baeldung.web.exception.CustomException3;
+import com.baeldung.web.exception.CustomException4;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.mockito.Mockito.when;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ *
+ *  We'll start only the web layer.
+ *
+ */
+@RunWith(SpringRunner.class)
+@WebMvcTest(FooController.class)
+public class GlobalExceptionHandlerIntegrationTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @MockitoBean
+    private IFooService service;
+
+    @MockitoBean
+    private ApplicationEventPublisher publisher;
+
+    @Test
+    public void delete_forException3_fromService() throws Exception {
+        when(service.findAll())
+                .thenThrow(new CustomException3());
+        this.mockMvc
+                .perform(get("/foos"))
+                .andExpect(status().isBadRequest());
+    }
+
+    @Test
+    public void delete_forException4Json_fromService() throws Exception {
+        when(service.findAll())
+                .thenThrow(new CustomException4("TEST"));
+        this.mockMvc
+                .perform(get("/foos").accept(MediaType.APPLICATION_JSON))
+                .andExpect(status().isBadRequest())
+                .andExpect(content().contentTypeCompatibleWith(MediaType.APPLICATION_JSON));
+    }
+
+    @Test
+    public void delete_forException4Text_fromService() throws Exception {
+        when(service.findAll())
+                .thenThrow(new CustomException4("TEST"));
+        this.mockMvc
+                .perform(get("/foos").accept(MediaType.TEXT_PLAIN))
+                .andExpect(status().isBadRequest())
+                .andExpect(content().contentTypeCompatibleWith(MediaType.TEXT_PLAIN));
+    }
+
+}