Question

我有一个简单的hashmap calss，我希望通过Jersey发送为JSON。有没有人有关于如何执行此类操作的示例，我尝试了以下

package de.vogella.jersey.first;
import java.util.HashMap;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import com.sun.jersey.api.view.Viewable;


// This method is called if XML is request
@GET
@Produces({ MediaType.APPLICATION_XML,MediaType.APPLICATION_JSON })

public HashMap sayXMLHello() {

  HashMap map = new HashMap();
    map.put( new Integer( 2 ), "two" );
    map.put( new Integer( 4 ), "four" );
 return map;
 }

 // This method is called if HTML is request
@GET
@Produces(MediaType.TEXT_HTML)
public String sayHtmlHello() {
return "<html> " + "<title>" + "Hello Jersey" + "</title>"
    + "<body><h1>" + "Hello Jersey" + "</body></h1>" + "</html> ";
}
}

然后是客户

package de.vogella.jersey.first;

import java.net.URI;
import java.util.HashMap;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.UriBuilder;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.client.config.ClientConfig; 
import com.sun.jersey.api.client.config.DefaultClientConfig;

 public class Test {
 public static void main(String[] args) {
 ClientConfig config = new DefaultClientConfig();
 Client client = Client.create(config);
  WebResource service = client.resource(getBaseURI());
  // Calls the HashMap function       
  System.out.println( service.path("rest")
                                  .path("hello")
                                  .accept(MediaType.APPLICATION_JSON)
                                  .get(HashMap.class));

  // The HTML
   System.out.println(service.path("rest")
                                  .path("hello")
                                  .accept(MediaType.TEXT_HTML)
                                  .get(String.class));

   }

 private static URI getBaseURI() {
 return UriBuilder.fromUri("http://localhost:8080/de.vogella.jersey.first").build();
 } 

 }

一旦我部署并调用客户端类，我就会收到以下错误：

Exception in thread "main" com.sun.jersey.api.client.UniformInterfaceException: GET       http://localhost:8080/de.vogella.jersey.first/rest/hello 
returned a response status of 500 Internal Server Error
at com.sun.jersey.api.client.WebResource.handle(WebResource.java:686)
at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74)
at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:507)
at de.vogella.jersey.first.Test.main(Test.java:25)

所以关于如何使用Jersey将HashMap对象从服务器发送到客户端的任何想法？我也无法将HashMap对象映射到POJO，因为它没有统一的结构（一直在变化）

感谢。

Answer 1

似乎是一个旧线程，回答它可能对某人有帮助。

首先，正如其他人所说，500错误很可能是由于服务器端代码出现问题而与客户端无关。

要在jersey客户端中获取Map类型的hashmap，请使用GenericType，如下面的代码所示。

 ClientConfig config = new DefaultClientConfig();
 Client client = Client.create(config);
  WebResource service = client.resource(getBaseURI());
  // Calls the HashMap function       
  System.out.println( service.path("rest")
                                  .path("hello")
                                  .accept(MediaType.APPLICATION_JSON)
                                  .get(new GenericType<Map<String, String>>() {}));

Answer 2

首先弄清楚服务器端的异常是什么。这可能比在完全解决问题之前发布问题要好得多解释实际问题。

Answer 3

这是通过REST服务

发送hashmap数据的示例代码

// CLIENT SIDE
package testHashMap;

import java.util.HashMap;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.ws.rs.core.MediaType;

import org.codehaus.jackson.map.ObjectMapper;

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


public class SendHashMap extends HttpServlet{


    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public void doPost(HttpServletRequest request,HttpServletResponse response){
        HashMapAcceptModel model = new HashMapAcceptModel();
        HashMap<String, String> positionList = new HashMap<String, String>();
        positionList.put("Key1", "Value1");
        positionList.put("Key2", "Value2");
        positionList.put("Key3", "Value3");
        model.setCompleteHashMapListList(positionList);
        try {
                Client client = Client.create();
                ObjectMapper mapper = new ObjectMapper();
                String JSONData = mapper.writeValueAsString(model);
                System.out.println("JSON Object :"+JSONData);
                WebResource webResource = client.resource("http://localhost:8080/RESTServer/gtl/json/metallica/JSONHashMapData");
                ClientResponse clientResponse = webResource.type(MediaType.APPLICATION_JSON).post(ClientResponse.class, JSONData);
                System.out.println("Client Response :"+clientResponse.getEntity(String.class));         
            } catch (Exception e) {
                e.printStackTrace();
            }
    }
}

***********************************************************************************************************************************************************************
// CLIENT SIDE
package testHashMap;

import java.util.HashMap;

public class HashMapAcceptModel {

public HashMap<String, String> completeHashMapListList = new HashMap<String, String>();

    public HashMap<String, String> getCompleteHashMapListList() {
        return completeHashMapListList;
    }
    public void setCompleteHashMapListList(HashMap<String, String> completeHashMapListList) {
        this.completeHashMapListList = completeHashMapListList;
    }


    @Override
    public String toString() {
        return "HashMapAcceptModel [completeHashMapListList="
                + completeHashMapListList + "]";
    }
}

***********************************************************************************************************************************************************************
// SERVER SIDE

package testHashMap;


import java.util.HashMap;

import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;



@Path("/json/metallica")
public class JSONService {

    public static HashMap<String, String> positionList = new HashMap<String, String>();


    @POST
    @Path("/JSONHashMapData")
    @Consumes(MediaType.APPLICATION_JSON)
    public Response addLocationMap(HashMapAcceptModel hashmapModel){

        System.out.println("result :"+hashmapModel.getCompleteHashMapListList());
        String result = "Success";
        System.out.println("result :"+result);
        return Response.status(201).entity(result).build();
    }
}

***********************************************************************************************************************************************************************
// SERVER SIDE

package testHashMap;

import java.util.HashMap;

public class HashMapAcceptModel {

public HashMap<String, String> completeHashMapListList = new HashMap<String, String>();

    public HashMap<String, String> getCompleteHashMapListList() {
        return completeHashMapListList;
    }
    public void setCompleteHashMapListList(HashMap<String, String> completeHashMapListList) {
        this.completeHashMapListList = completeHashMapListList;
    }


    @Override
    public String toString() {
        return "HashMapAcceptModel [completeHashMapListList="
                + completeHashMapListList + "]";
    }
}

***********************************************************************************************************************************************************************

您可能需要使用这些库文件

enter image description here

Answer 4

Jersey不为HashMap提供MessageBodyWriter。您需要编写自定义MessageBodyWriter。请参阅this link

如何通过Jersey Web服务框架发送HashMap对象？

4 个答案: