从servlet的

Question

发送JSON我写这个servlet：通过AJAX请求和servlet的我回报他们

protected void doPost(HttpServletRequest request, HttpServletResponse response) 
     throws ServletException, IOException { 

    response.setContentType("application/json"); 

    BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream())); 
    String json = ""; 
    if(br != null){ 
     json = br.readLine(); 
    } 

    PrintWriter out = response.getWriter(); 

    out.write(json); 
    out.flush(); 
} 

发送数据。 的问题是，当我试图让我返回内部的servlet创建一个JSONObject给了我错误500

，让我这个错误代码：

protected void doPost(HttpServletRequest request, HttpServletResponse response) 
     throws ServletException, IOException { 




    response.setContentType("application/json"); 

    BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream())); 

    JSONObject json = new JSONObject(); 

    json.put("name", "federico"); 

    PrintWriter out = response.getWriter(); 

    out.print(json); 
    out.flush(); 
} 

我requestAjax是：

$.ajax({ 
       url: "ValidServlet", 
       type: 'POST', 
       data : JSON.stringify(submitFormData), 
       success: function (data) { 
        alert(data.name); 
       }, 
       error: function (data) { 
        alert('error'); 
       } 
      }); 

我的错误是：

Failed to load resource: the server responded with a status of 500 (Internal Server Error) (17:33:34:492 | error, network)at http://localhost:8080/ProgettoProsa/ValidServlet> 

也许我wron g返回所以json？

帮我找出我失败的地方。

谢谢大家。

Answer 1

试试这个代码与HTTP发送JSON数据：

 
    package com.nl.services.ws.sincronizacao;
 

import java.io.IOException; 
import java.io.PrintWriter; 
import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import com.google.gson.Gson; 

@WebServlet(value = "/TestGsonHttp") 
public class TestGsonHttp extends HttpServlet { 

    @Override 
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 

     // Your class 
     MyJson m = new MyJson(); 
     m.setName("frederico"); 

     Gson g = new Gson(); 
     String jsonResult = g.toJson(m); 

     PrintWriter writer = resp.getWriter(); 
     writer.print(jsonResult); 
     writer.flush(); 
     writer.close(); 
    } 

    class MyJson { 

     private String name; 

     public String getName() { 
      return name; 
     } 

     public void setName(String name) { 
      this.name = name; 
     } 
    } 
}