ajax用json實現數據傳輸


 JSON(JavaScript Object Notation) 是一種輕量級的數據交換格式。它基於ECMAScript的一個子集。 JSON采用完全獨立於語言的文本格式,但是也使用了類似於C語言家族的習慣(包括C、C++、C#Java、JavaScript、PerlPython等)。這些特性使JSON成為理想的數據交換語言。 易於人閱讀和編寫,同時也易於機器解析和生成(一般用於提升網絡傳輸速率)。

json簡單說就是javascript中的對象和數組,所以這兩種結構就是對象和數組兩種結構,通過這兩種結構可以表示各種復雜的結構。
1、對象:對象在js中表示為“{}”括起來的內容,數據結構為 {key:value,key:value,...}的鍵值對的結構,在面向對象的語言中,key為對象的屬性,value為對應的屬性值,所以很容易理解,取值方法為 對象.key 獲取屬性值,這個屬性值的類型可以是 數字、字符串、數組、對象幾種。
2、數組:數組在js中是中括號“[]”括起來的內容,數據結構為 ["java","javascript","vb",...],取值方式和所有語言中一樣,使用索引獲取,字段值的類型可以是 數字、字符串、數組、對象幾種。
經過對象、數組2種結構就可以組合成復雜的數據結構了。
 
 
使用JSON前需要先的導入json.jar包

傳輸單個對象:

新建一個 servlet

package com.itnba.maya.a;

import java.io.IOException;
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 org.json.JSONObject;

/**
 * Servlet implementation class C
 */
@WebServlet("/C")
public class C extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public C() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        //模擬從數據庫中查處
        Dog a=new Dog();
        a.setName("小黃");
        a.setAge(5);
        a.setZl("哈士奇");
        
        JSONObject obj=new JSONObject();
        obj.put("name", a.getName());
        obj.put("age", a.getAge());
        obj.put("zl", a.getZl());
        
        JSONObject bb=new JSONObject();
        bb.put("obj", obj);
        
        response.getWriter().append(bb.toString());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

效果如下:

jsp頁面

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
    $("#k").click(function(){
        $.ajax({
            url:"C",
            data:{},
            type:"POST",
            dataType:"JSON",
            success:function(httpdata){
                $("#x").append("<li>"+httpdata.obj.name+"</li>");
                $("#x").append("<li>"+httpdata.obj.age+"</li>");
                $("#x").append("<li>"+httpdata.obj.zl+"</li>")
            }
        })
    });
});
</script>
</head>
<body>
<span id="k">查看</span>
<h1>
<ul id="x">
</ul></h1>
</body>
</html>

 效果如下:

 傳輸集合或數組:

servlet:

package com.itnba.maya.a;

import java.io.IOException;
import java.util.ArrayList;

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 org.json.JSONArray;
import org.json.JSONObject;

/**
 * Servlet implementation class D
 */
@WebServlet("/D")
public class D extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public D() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        //模擬從數據庫中查出
        Dog a1=new Dog();
        a1.setName("小黃");
        a1.setAge(5);
        a1.setZl("哈士奇");
        
        Dog a2=new Dog();
        a2.setName("中黃");
        a2.setAge(6);
        a2.setZl("泰迪");
        
        Dog a3=new Dog();
        a3.setName("大黃");
        a3.setAge(7);
        a3.setZl("京巴");
        
        ArrayList<Dog> list=new ArrayList<Dog>();
        list.add(a1);
        list.add(a2);
        list.add(a3);
        
        JSONArray arr= new JSONArray();
        //遍歷集合
        for(Dog d:list){
            JSONObject obj=new JSONObject();
            obj.put("name", d.getName());
            obj.put("age", d.getAge());
            obj.put("zl", d.getZl());
            arr.put(obj);
        }

        response.getWriter().append(arr.toString());
    }
    

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

 效果如下:

jsp頁面:

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
    $("#k").click(function(){
        $.ajax({
            url:"D",
            data:{},
            type:"POST",
            dataType:"JSON",
            success:function(httpdata){
                for(var i=0;i<httpdata.length;i++){
                    var n=httpdata[i].name
                    var a=httpdata[i].age
                    var z=httpdata[i].zl
                    var tr="<tr>"
                        tr+="<td>"+n+"</td>"
                        tr+="<td>"+a+"</td>"
                        tr+="<td>"+z+"</td>"
                        tr+="</tr>"
                        $("#x").append(tr)
                }    
            }
        })
    });
});
</script>

</head>
<body>
<span id="k">查看</span>
<h1>
<table width="100%" id="x" border="1px">
</table>
</h1>
</body>
</html>

 

 效果如下:

 


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