JSONP跨域数据调用

浏览数：31 / 时间：2015年06月09日

引自：http://kb.cnblogs.com/page/139725/

Web页面上调用js文件时则不受是否跨域的影响（不仅如此，我们还发现凡是拥有”src”这个属性的标签都拥有跨域的能力，比如<script>、<img>、<iframe>）

<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
<!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=GB18030">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="jquery-1.9.1.js"></script>

<script>
    

    function handleData(data){
        alert(JSON.stringify(data)); 
        
    }
    
    function loadData(){
        var url = "/myweb/TestJsonp?code=CA1998&callback=handleData";  //跨域url
        // 提供jsonp服务的url地址（不管是什么类型的地址，最终生成的返回值都是一段javascript代码）
        // 创建script标签，设置其属性
        var script = document.createElement(‘script‘);
        script.setAttribute(‘src‘, url);
        // 把script标签加入head，此时调用开始
        document.getElementsByTagName(‘head‘)[0].appendChild(script);
    }
    
    
    function loadAjax(){
        var url = "/myweb/TestJsonp?code=CA1998"; //跨域url
        $.ajax({
            type: "get",  //jsonp 类型下只能使用GET,不能用POST,这里不写默认为GET
            async: false,
            url: url,
            dataType: "jsonp",
            jsonp: "callback",//传递给请求处理程序或页面的，用以获得jsonp回调函数名的参数名(一般默认为:callback)
           // jsonpCallback:"handleData",//自定义的jsonp回调函数名称，默认为jQuery自动生成的随机函数名，也可以写"?"，jQuery会自动为你处理数据
            success: function(json){
                handleData(json);
                alert(‘您查询到航班信息‘);
            },
            error: function(){
                alert(‘fail‘);
            }
        });
    }
</script>
<body onload="loadAjax()">

</body>
</html>

package bookstore;

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;

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

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

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        String code = request.getParameter("code");
        String callback = request.getParameter("callback");
        response.getWriter().write(  
                callback+"({code:‘"+code+"‘})");   
    }

}