如何在Ajax中使用JSON

    页面：jsonExample.jsp

<%@ page cOntentType="text/html; charset=GBK" %>












 

  服务器响应：

    服务器：JSONExample.java

package ajaxbook.chap4;

import java.io.*;
import java.net.*;
import java.text.ParseException;
import javax.servlet.*;
import javax.servlet.http.*;
import org.json.JSONObject;

public class JSONExample
    extends HttpServlet {
  //处理Post方法
  protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
      IOException {
    String json = readJSONStringFromRequestBody(request);

    //使用JSON绑字Ajax对象
    JSONObject jsOnObject= null;
    try {
      jsOnObject= new JSONObject(json);
    }
    catch (ParseException pe) {
      System.out.println("ParseException: " + pe.toString());
    }

    //返回输出结果
    String respOnseText= "You have a " + jsonObject.getInt("year") + " "
        + jsonObject.getString("make") + " " + jsonObject.getString("model")
        + " " + " that is " + jsonObject.getString("color") + " in color.";

    response.setContentType("text/xml");
    response.getWriter().print(responseText);
  }

  //得到参数
  private String readJSONStringFromRequestBody(HttpServletRequest request) {
    StringBuffer json = new StringBuffer();
    String line = null;
    try {
      BufferedReader reader = request.getReader();
      while ( (line = reader.readLine()) != null) {
        json.append(line);
      }
    }
    catch (Exception e) {
      System.out.println("Error reading JSON string: " + e.toString());
    }
    return json.toString();
  }
}

注意：要引入json.js和json的源文件，使用json.jar不行，源文件参见书籍源代码第三章