Json概要

JSON：JavaScript     （JavaScriptObjectNotation）。
JSON             。  XML。
JSON XML  、  ，    。

JSON  
{"name":"  ","age":22}

JSON  
{
    "student":[
        {"name":"  ","age":22},
        {"name":"  ","age":23},
        {"name":"  ","age":24}
    ]
}

JSON  
{
    "student":[
        {"name":"  ","age":22,"score":{"chinese":90,"math":100,"english":80}},
        {"name":"  ","age":23,"score":{"chinese":70,"math":90,"english":90}},
        {"name":"  ","age":24,"score":{"chinese":80,"math":60,"english":90}}
    ]
}
 Json   Json  
vardataObj = eval("("+data+")"); //    json  

Json-lib

  jar 

commons-beanutils-1.7.0.jar
commons-collections-3.2.jar
commons-lang-2.4.jar
commons-logging-1.0.4.jar
ezmorph-1.0.3.jar
json-lib-2.2.3-jdk15.jar

GetAjaxInfoServlet.java

package com.andrew.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class GetAjaxInfoServlet extends HttpServlet{

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        String action=request.getParameter("action");
        if("jsonObject".equals(action)){
            this.getJsonObject(request, response);
        }else if("jsonArray".equals(action)){
            this.getJsonArray(request, response);
        }else if("jsonNested".equals(action)){
            this.getJsonNested(request, response);
        }
        
    }
    
    private void getJsonObject(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out=response.getWriter();
        // String resultJson="{\"name\":\"  \",\"age\":22}";
        JSONObject resultJson=new JSONObject();
        resultJson.put("name", "  ");
        resultJson.put("age", 22);
        out.println(resultJson);
        out.flush();
        out.close();
    }
    
    private void getJsonArray(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out=response.getWriter();
        JSONObject resultJson=new JSONObject();
        JSONArray jsonArray=new JSONArray();
        JSONObject jsonObject1=new JSONObject();
        jsonObject1.put("name", "  ");
        jsonObject1.put("age", 22);
        JSONObject jsonObject2=new JSONObject();
        jsonObject2.put("name", "  ");
        jsonObject2.put("age", 23);
        JSONObject jsonObject3=new JSONObject();
        jsonObject3.put("name", "  ");
        jsonObject3.put("age", 24);
        jsonArray.add(jsonObject1);
        jsonArray.add(jsonObject2);
        jsonArray.add(jsonObject3);
        
        resultJson.put("students", jsonArray);
        out.println(resultJson);
        out.flush();
        out.close();
    }
    
    private void getJsonNested(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out=response.getWriter();
        JSONObject resultJson=new JSONObject();
        JSONArray jsonArray=new JSONArray();
        JSONObject jsonObject1=new JSONObject();
        jsonObject1.put("name", "  ");
        jsonObject1.put("age", 22);
        
        JSONObject scoreObject1=new JSONObject();
        scoreObject1.put("chinese", 90);
        scoreObject1.put("math", 100);
        scoreObject1.put("english", 80);
        jsonObject1.put("score", scoreObject1);
        
        JSONObject jsonObject2=new JSONObject();
        jsonObject2.put("name", "  ");
        jsonObject2.put("age", 23);
        
        JSONObject scoreObject2=new JSONObject();
        scoreObject2.put("chinese", 70);
        scoreObject2.put("math", 90);
        scoreObject2.put("english", 90);
        jsonObject2.put("score", scoreObject2);
        
        JSONObject jsonObject3=new JSONObject();
        jsonObject3.put("name", "  ");
        jsonObject3.put("age", 24);
        
        JSONObject scoreObject3=new JSONObject();
        scoreObject3.put("chinese", 80);
        scoreObject3.put("math", 60);
        scoreObject3.put("english", 90);
        jsonObject3.put("score", scoreObject3);
        
        jsonArray.add(jsonObject1);
        jsonArray.add(jsonObject2);
        jsonArray.add(jsonObject3);
        
        resultJson.put("students", jsonArray);
        out.println(resultJson);
        out.flush();
        out.close();
    }
}

web.xml


      getAjaxInfoServlet
      com.andrew.web.GetAjaxInfoServlet


      getAjaxInfoServlet
      /getAjaxInfo


ajax.jsp








    function loadInfo(){
        var xmlHttp;
        if(window.XMLHttpRequest){
            xmlHttp=new XMLHttpRequest();
        }else{
            xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
        }
        xmlHttp.onreadystatechange = function(){
            if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
                alert(xmlHttp.responseText);
                var dataObj=eval("("+xmlHttp.responseText+")");
                alert(dataObj.name);
                alert(dataObj.age);
                document.getElementById("name").value=dataObj.name;
                document.getElementById("age").value=dataObj.age;
            }
        };
        xmlHttp.open("get", "getAjaxInfo?action=jsonObject", true);
        xmlHttp.send();
    }
    
    function loadInfo2(){
        var xmlHttp;
        if(window.XMLHttpRequest){
            xmlHttp=new XMLHttpRequest();
        }else{
            xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
        }
        xmlHttp.onreadystatechange=function(){
            if(xmlHttp.readyState==4 && xmlHttp.status==200){
                alert(xmlHttp.responseText);
                var dataObj=eval("("+xmlHttp.responseText+")");
                var st=document.getElementById("studentTable");
                alert(dataObj.students.length);
                var newTr; //  
                var newTd0; //    
                var newTd1; //    
                var newTd2; //    
                for(var i=0;i<dataObj.students.length;i++){
                    var student=dataObj.students[i];
                    newTr=st.insertRow();
                    newTd0=newTr.insertCell();
                    newTd1=newTr.insertCell();
                    newTd2=newTr.insertCell();
                    newTd0.innerHTML=student.name;
                    newTd1.innerHTML=student.age;
                    newTd2.innerHTML="  :"+student.score.chinese+",  :"+student.score.math+",  :"+student.score.english;
                }
            }
        };
        // xmlHttp.open("get", "getAjaxInfo?action=jsonArray", true);
        xmlHttp.open("get", "getAjaxInfo?action=jsonNested", true);
        xmlHttp.send();
    }




    
    ：    ：
    

        

        
    




http://localhost:8080/HeadFirstAjaxJsonChap03/ajax.jsp
  Ajax  
  
22
  Ajax  2
      22      :90,  :100,  :80
      23      :70,  :90,  :90
      24      :80,  :60,  :90