BAEL-842 improvement to the spring controller return image or file in controller example: add a dynamic example

spring-boot-modules/spring-boot-mvc-3/pom.xml

@@ -40,6 +40,18 @@
             <artifactId>commons-io</artifactId>
             <version>${commons-io.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
+    <build>
+        <resources>
+            <resource>
+                <directory>/src/main/resources</directory>
+            </resource>
+        </resources>
+    </build>
 </project>

spring-boot-modules/spring-boot-mvc-3/src/main/java/com/baeldung/produceimage/controller/DataProducerController.java

@@ -1,9 +1,12 @@
 package com.baeldung.produceimage.controller;
 
 import org.apache.commons.io.IOUtils;
+import org.springframework.core.io.InputStreamResource;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 
 import java.io.IOException;
@@ -29,6 +32,18 @@ public class DataProducerController {
         return IOUtils.toByteArray(in);
     }
 
+    @GetMapping("/get-image-dynamic-type")
+    @ResponseBody
+    public ResponseEntity<InputStreamResource> getImageDynamicType(@RequestParam("jpg") boolean jpg) {
+        final MediaType contentType = jpg ? MediaType.IMAGE_JPEG : MediaType.IMAGE_PNG;
+        final InputStream in = jpg ?
+                getClass().getResourceAsStream("/com/baeldung/produceimage/image.jpg") :
+                getClass().getResourceAsStream("/com/baeldung/produceimage/image.png");
+        return ResponseEntity.ok()
+                .contentType(contentType)
+                .body(new InputStreamResource(in));
+    }
+
     @GetMapping(value = "/get-file", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
     public @ResponseBody byte[] getFile() throws IOException {
         final InputStream in = getClass().getResourceAsStream("/com/baeldung/produceimage/data.txt");

spring-boot-modules/spring-boot-mvc-3/src/main/resources/com/baeldung/produceimage/data.txt

@@ -0,0 +1 @@
+Hello Baeldung!

spring-boot-modules/spring-boot-mvc-3/src/test/java/com/baeldung/produceimage/DataProducerControllerIntegrationTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.produceimage;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+import org.springframework.web.context.WebApplicationContext;
+
+@SpringBootTest(classes = ImageApplication.class,
+        webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public class DataProducerControllerIntegrationTest {
+
+    @Autowired
+    private WebApplicationContext webApplicationContext;
+
+    private MockMvc mockMvc;
+
+    @BeforeEach
+    public void setup() {
+        this.mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
+    }
+
+    @Test
+    void givenJpgTrue_whenGetImageDynamicType_ThenContentTypeIsJpg() throws Exception {
+        mockMvc.perform(get("/get-image-dynamic-type?jpg=true"))
+                .andExpect(status().isOk())
+                .andExpect(content().contentType(MediaType.IMAGE_JPEG))
+                .andExpect(header().stringValues(HttpHeaders.CONTENT_TYPE, MediaType.IMAGE_JPEG_VALUE));
+    }
+
+    @Test
+    void givenJpgFalse_whenGetImageDynamicType_ThenContentTypeIsFalse() throws Exception {
+        mockMvc.perform(get("/get-image-dynamic-type?jpg=false"))
+                .andExpect(status().isOk())
+                .andExpect(content().contentType(MediaType.IMAGE_PNG))
+                .andExpect(header().stringValues(HttpHeaders.CONTENT_TYPE, MediaType.IMAGE_PNG_VALUE));
+    }
+
+}