将JSON响应解析为对象 [英] Parse a JSON response as an object

问题描述

晚上好，

我是网络服务的新手，我只想编写一个简单的客户端，只需从REST调用中获取响应。

我下载并添加 jersey-bundle-1.17.1.jar 到我的构建路径，我发现了一段代码，它对一个url进行REST调用，并以<$ c $的形式返回一个响应C>字符串。

Good evening,
I am a newbie in web services and i just want to write a simple client that simply gets responses from REST calls.
I downloaded and added jersey-bundle-1.17.1.jar to my build path and i found a working piece of code that makes a REST call to a url and returns a response as a String.

import javax.ws.rs.core.MediaType;

import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;

public class TestJerseyClient {
    public static void main(String[] args) {
        try {
            Client client = Client.create();
            WebResource webResource = client
                    .resource("http://path/to/service");

            ClientResponse response = webResource
                    .accept(MediaType.APPLICATION_JSON)
                    .get(ClientResponse.class);

            if (response.getStatus() != 200)
                throw new RuntimeException("Failed : HTTP error code : " + response.getStatus());

            String output = response.getEntity(String.class);

            System.out.println("Output from Server .... \n");
            System.out.println(output);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

但我不想要做字符串操作以获得我感兴趣的响应部分。

But i don't want to do string manipulations to get the parts of the response that im interested in.

我更喜欢更结构化的方法，比如获取对象而不是字符串

（ JSON 对象，地图< K，V> 对象等...）

I would prefer a more structured approach, like getting an Object instead of a string
(a JSON Object, a Map<K,V> Object, etc...)

---

尝试＃1 - 地图< K，V>

Sep 15, 2013 2:46:13 AM com.sun.jersey.api.client.ClientResponse getEntity
SEVERE: A message body reader for Java class java.util.Map, and Java type java.util.Map<java.lang.String, java.lang.Object>, and MIME media type application/json; charset=UTF-8 was not found
Sep 15, 2013 2:46:13 AM com.sun.jersey.api.client.ClientResponse getEntity
SEVERE: The registered message body readers compatible with the MIME media type are:
application/json; charset=UTF-8 ->
  com.sun.jersey.json.impl.provider.entity.JSONJAXBElementProvider$App
  com.sun.jersey.json.impl.provider.entity.JSONRootElementProvider$App
  com.sun.jersey.json.impl.provider.entity.JSONListElementProvider$App
*/* ->
  com.sun.jersey.core.impl.provider.entity.FormProvider
  com.sun.jersey.core.impl.provider.entity.StringProvider
  com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
  com.sun.jersey.core.impl.provider.entity.FileProvider
  com.sun.jersey.core.impl.provider.entity.InputStreamProvider
  com.sun.jersey.core.impl.provider.entity.DataSourceProvider
  com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$General
  com.sun.jersey.core.impl.provider.entity.ReaderProvider
  com.sun.jersey.core.impl.provider.entity.DocumentProvider
  com.sun.jersey.core.impl.provider.entity.SourceProvider$StreamSourceReader
  com.sun.jersey.core.impl.provider.entity.SourceProvider$SAXSourceReader
  com.sun.jersey.core.impl.provider.entity.SourceProvider$DOMSourceReader
  com.sun.jersey.json.impl.provider.entity.JSONJAXBElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General
  com.sun.jersey.core.impl.provider.entity.XMLRootObjectProvider$General
  com.sun.jersey.core.impl.provider.entity.EntityHolderReader
  com.sun.jersey.json.impl.provider.entity.JSONRootElementProvider$General
  com.sun.jersey.json.impl.provider.entity.JSONListElementProvider$General

com.sun.jersey.api.client.ClientHandlerException: A message body reader for Java class java.util.Map, and Java type java.util.Map<java.lang.String, java.lang.Object>, and MIME media type application/json; charset=UTF-8 was not found
    at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:561)
    at com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:535)
    at com.sun.jersey.api.client.WebResource.handle(WebResource.java:696)
    at com.sun.jersey.api.client.WebResource.access$300(WebResource.java:74)
    at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:512)
    at rest.TestJerseyClientAdvanced.main(TestJerseyClientAdvanced.java:36)

推荐答案

我建议你使用Jackson（un ）编组JSON响应。这可以通过以下两个步骤完成。

I recommend you use Jackson for (un)marshalling JSON responses. This can be done is two steps as below.

Step1。创建一个java bean，其成员/对象名称与预期的响应匹配。例如，MyResponse.class

Step1. create a java bean with member/object names that match the expected response. e.g, MyResponse.class

Step2。从客户端响应中读取实体时使用java bean。

Step2. use the java bean when reading the entity from the client response.

private static ClientConfig clientConfig = new DefaultClientConfig();
clientConfig.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, Boolean.TRUE);

ClientResponse response =  Client.create(clientConfig).
            resource(uri).accept(MediaType.APPLICATION_JSON).
            header("content-type", MediaType.APPLICATION_JSON).
            get(MY_RESPONSE.class); 
MyResponse output = response.getEntity(MyResponse.class);

这篇关于将JSON响应解析为对象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！