“无法找到可接受的代表”使用spring-boot-starter-web [英] "Could not find acceptable representation" using spring-boot-starter-web

问题描述

我正在尝试使用 spring-boot-starter-web 来创建一个提供Java对象的JSON表示的休息服务。根据我的理解，这个boot-starter-web jar应该自动处理通过Jackson转换为JSON，但我得到了这个错误。

I am trying to use spring-boot-starter-web to create a rest service serving up JSON representations of Java objects. From what I understand this boot-starter-web jar is supposed to handle the conversion to JSON through Jackson automatically but I am instead getting this error.

{ "timestamp": 1423693929568,
  "status": 406,
  "error": "Not Acceptable",
  "exception": "org.springframework.web.HttpMediaTypeNotAcceptableException",
  "message": "Could not find acceptable representation"
}

我的控制器就是这个......

My Controller is this...

@RestController
@RequestMapping(value = "/media")
public class MediaController {
    @RequestMapping(value = "/test", method = RequestMethod.POST)
    public @ResponseBody UploadResult test(@RequestParam(value="data") final String data) {
      String value = "hello, test with data [" + data + "]"; 
      return new UploadResult(value);
    }

    @RequestMapping(value = "/test2", method = RequestMethod.POST)
    public int test2() {
        return 42;
    }

    @RequestMapping(value = "/test3", method = RequestMethod.POST)
    public String test3(@RequestParam(value="data") final String data) {
        String value = "hello, test with data [" + data + "]"; 
        UploadResult upload = new UploadResult(value);
        return upload.value;
    }


    public static class UploadResult {
        private String value;
        public UploadResult(final String value)
        {
            this.value = value;
        }
    }
}

我的 pom.xml 有...

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>1.2.1.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-tomcat</artifactId>
        <version>1.2.1.RELEASE</version>
        <scope>provided</scope>
    </dependency>

mvn依赖：树显示春天 - boot-starter-web确实依赖于jackson2.4数据绑定，因此应该在类路径上...

mvn dependency:tree shows that spring-boot-starter-web does indeed depend on the jackson2.4 databind and thus should be on the classpath...

[INFO] +- org.springframework.boot:spring-boot-starter-web:jar:1.2.1.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot-starter:jar:1.2.1.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot:jar:1.2.1.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-autoconfigure:jar:1.2.1.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-logging:jar:1.2.1.RELEASE:compile
[INFO] |  |  |  +- org.slf4j:jul-to-slf4j:jar:1.7.8:compile
[INFO] |  |  |  \- org.slf4j:log4j-over-slf4j:jar:1.7.8:compile
[INFO] |  |  \- org.yaml:snakeyaml:jar:1.14:runtime
[INFO] |  +- com.fasterxml.jackson.core:jackson-databind:jar:2.4.4:compile
[INFO] |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.4.0:compile
[INFO] |  |  \- com.fasterxml.jackson.core:jackson-core:jar:2.4.4:compile
[INFO] |  +- org.hibernate:hibernate-validator:jar:5.1.3.Final:compile
[INFO] |  |  +- javax.validation:validation-api:jar:1.1.0.Final:compile
[INFO] |  |  +- org.jboss.logging:jboss-logging:jar:3.1.3.GA:compile
[INFO] |  |  \- com.fasterxml:classmate:jar:1.0.0:compile
[INFO] |  +- org.springframework:spring-web:jar:4.1.4.RELEASE:compile
[INFO] |  |  +- org.springframework:spring-aop:jar:4.1.4.RELEASE:compile
[INFO] |  |  |  \- aopalliance:aopalliance:jar:1.0:compile
[INFO] |  |  +- org.springframework:spring-beans:jar:4.1.4.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-context:jar:4.1.4.RELEASE:compile
[INFO] |  \- org.springframework:spring-webmvc:jar:4.1.4.RELEASE:compile
[INFO] |     \- org.springframework:spring-expression:jar:4.1.4.RELEASE:compile

。 ..但是调用 test 服务会产生上述错误。 test2 和 test3 工作正常，证明它必须只是尝试转换为失败的JSON？我错过了一些配置问题或注释吗？从我可以找到的所有示例中，不再需要为基本的Jackson JSON转换注释类。

... yet calling the test service gives the error mentioned above. test2 and test3 work fine proving that it must just be the attempted conversion to JSON that is failing? Am I missing some configuration problem or annotations? From all the examples I can find, annotating the class for basic Jackson JSON conversion is no longer necessary.

任何帮助都非常感谢。

推荐答案

您的UpdateResult没有公共getter，例如：

You have no public getters for your UpdateResult, for example :

public static class UploadResult {
    private String value;
    public UploadResult(final String value)
    {
        this.value = value;
    }

    public String getValue() {
       return this.value;
    }
}

我相信默认情况下自动发现已启用并将尝试发现你的吸气剂。您可以使用 @JsonAutoDetect（getterVisibility = Visibility.NONE）禁用它，在您的示例中将导致 [] 。

I believe by default auto discovery is on and will try to discover your getters. You can disable it with @JsonAutoDetect(getterVisibility=Visibility.NONE), and in your example will result in [].

这篇关于“无法找到可接受的代表”使用spring-boot-starter-web的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！