我正在尝试返回此处显示的图像https://www.baeldung.com/spring-mvc-image-media-data
那里显示的所有方法都可以正常工作，除了最后一种。
@ResponseBody
@RequestMapping(value = "/image-resource", method = RequestMethod.GET)
public Resource getImageAsResource() {
return new ServletContextResource(servletContext, "/WEB-INF/images/image-example.jpg");
}
或者，如果我们想要更多地控制响应头：
@RequestMapping(value = "/image-resource", method = RequestMethod.GET)
@ResponseBody
public ResponseEntity<Resource> getImageAsResource() {
HttpHeaders headers = new HttpHeaders();
Resource resource =
new ServletContextResource(servletContext, "/WEB-INF/images/image-example.jpg");
return new ResponseEntity<>(resource, headers, HttpStatus.OK);
}
使用此方法时，我收到错误消息：根据请求中收到的主动协商标头字段，目标资源没有用户代理可以接受的当前表示，并且服务器不愿意提供默认表示.
我尝试了很多选择，但没有一个有帮助。我研究了这些页面
HTTP 状态 406 - 在 Spring MVC 中不可接受
使用 spring-boot-starter-web “找不到可接受的表示”
和许多其他人，这些页面上的答案都没有帮助解决问题。
如果我做：
@GetMapping(value = "/image4", produces = "image/jpeg")
然后我得到错误：No converter for [class org.springframework.web.context.support.ServletContextResource] with preset Content-Type 'null'
如果我做：
@GetMapping(value = "/image4", consumes = "image/jpeg")
然后我收到错误消息：源服务器拒绝为请求提供服务，因为有效负载的格式不受目标资源上此方法的支持。
这是我的 github 项目https://github.com/MyTestPerson/images
请告诉我我做错了什么？
图像类
@Controller
public class Image {
@Autowired
ServletContext servletContext;
@ResponseBody()
@GetMapping(value = "/image4")
public Resource getImage4() {
return new ServletContextResource(servletContext, "/WEB-INF/image/jackson.jpg");
}
@ResponseBody
@GetMapping(value = "/image5")
public ResponseEntity<Resource> getImage5() {
HttpHeaders headers = new HttpHeaders();
Resource resource = new ServletContextResource(servletContext, "/WEB-INF/image/jackson.jpg");
return new ResponseEntity<>(resource, headers, HttpStatus.OK);
}
}
RootConfig.class
@EnableWebMvc
@Configuration
public class RootConfig implements WebMvcConfigurer {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(byteArrayHttpMessageConverter());
}
@Bean
public ByteArrayHttpMessageConverter byteArrayHttpMessageConverter() {
ByteArrayHttpMessageConverter arrayHttpMessageConverter = new ByteArrayHttpMessageConverter();
arrayHttpMessageConverter.setSupportedMediaTypes(getSupportedMediaTypes());
return arrayHttpMessageConverter;
}
private List<MediaType> getSupportedMediaTypes() {
List<MediaType> list = new ArrayList<MediaType>();
list.add(MediaType.IMAGE_JPEG);
list.add(MediaType.IMAGE_PNG);
list.add(MediaType.APPLICATION_OCTET_STREAM);
return list;
}
}
POM.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.images</groupId>
<artifactId>images</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<encoding>${encoding}</encoding>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<failOnMissingWebXml>false</failOnMissingWebXml>
<java.version>11</java.version>
<encoding>UTF-8</encoding>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-framework-bom</artifactId>
<version>5.3.9</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-bom</artifactId>
<version>5.5.1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.junit</groupId>
<artifactId>junit-bom</artifactId>
<version>5.7.2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<!-- Spring Framework-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
</dependency>
<!-- Freemarker-->
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.31</version>
</dependency>
<!-- Servlet-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
<!-- Apache Commons IO-->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.11.0</version>
</dependency>
<!-- com fasterxml jackson data format-->
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.12.4</version>
</dependency>
<!-- Testing-->
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>3.19.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>3.8.0</version>
<scope>test</scope>
</dependency>
<!-- Logging-->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.30</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.30</version>
</dependency>
</dependencies>
</project>