如何从Java Rest API返回json对象 [英] how to return json objects from java rest api

问题描述

我正在尝试从jax-rs返回JSON对象，但是每当尝试访问时都会收到内部服务器错误.

I am trying to return a JSON object from a jax-rs but I get an internal server error whenever I try to access.

这是我的方法，我正在使用javax.ws.rs.GET.

This is my method, I am using javax.ws.rs.GET.

@GET
@Produces("application/json")
public Testy getJson() {
   return new Testy("hello");
}

这是课程:

public class Testy {

    private final String value;

    public Testy(String value){

        this.value = value;
    }

  public String getValue(){

      return value;
   }

}

我的Pom.xml具有此依赖关系，我尝试了各种依赖关系，但没有任何作用.球衣有各种Maven资源，其中有jersey-client jersey-core.

My Pom.xml has this dependency, I have tried various dependencies, but none work. There are various maven resources for jersey, there's jersey-client jersey-core.

<dependency>
 <groupId>com.fasterxml.jackson.jaxrs</groupId>
 <artifactId>jackson-jaxrs-json-provider</artifactId>
 <version>2.3.3</version>
</dependency>

我正在使用Glassfish 4.

I am using Glassfish 4.

有关使用Jersey的问题:

我已经看到一些位置，其中提到您需要进行初始化POJO支持，似乎适用于1. *版球衣，但我不确定.如果我使用的是2. *，我不需要这个吗?

I have seen some places where they mention you need to have initialize POJO support, it seems like its for jersey 1.* but I am not sure. I don't need this if I am using 2.* ?

我是否必须修改web.xml以指向jersey servlet?

如何使用POJO类生成和使用JSON对象！

这是我自动生成的配置类.

Here is my auto generated config class.

推荐答案

我必须将JacksonFeature资源添加到我的ApplicationConfig类中.

    @javax.ws.rs.ApplicationPath("webresources")
public class ApplicationConfig extends Application {

    @Override
    public Set<Class<?>> getClasses() {
        Set<Class<?>> resources = new java.util.HashSet<>();              
       addRestResourceClasses(resources);
       resources.add(org.glassfish.jersey.jackson.JacksonFeature.class);
        return resources;
    }

    /**
     * Do not modify addRestResourceClasses() method.
     * It is automatically populated with
     * all resources defined in the project.
     * If required, comment out calling this method in getClasses().
     */
    private void addRestResourceClasses(Set<Class<?>> resources) {
        resources.add(com.wfscorp.restapitwo.GenericResource.class);
    }

}

然后一切正常！

注意

当我使用com.fasterxml.jackson.jaxrs依赖项时，我无法部署我的应用程序.我开始出现WELD-001408 Unsatisfied dependencies for type错误，因此不得不排除球衣媒体的多个部分.

When I used the com.fasterxml.jackson.jaxrs dependency I was unable to deploy my application. I started getting a WELD-001408 Unsatisfied dependencies for type error so I had to exclude the jersey media multi part.

这些是我pom.xml中的依赖项

These are the dependencies in my pom.xml

 <dependencies>
    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-json-jackson</artifactId>
        <version>2.13</version>
        <type>jar</type>
    </dependency>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>7.0</version>
        <scope>provided</scope>
    </dependency> 

    <dependency>
        <groupId>com.fasterxml.jackson.jaxrs</groupId>
        <artifactId>jackson-jaxrs-json-provider</artifactId>
        <version>2.4.0</version>
    </dependency>

    <dependency>
        <groupId>org.glassfish.jersey.media</groupId>
        <artifactId>jersey-media-multipart</artifactId>
        <version>2.7</version>
        <scope>provided</scope>
    </dependency>

</dependencies>

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