Ajax&Json交互实例

共用的Servlet

GetAjaxInfoServlet.java

package com.ruanku.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);
	}
	/**
	 * 判断使用哪种Servlet
	 */
	@Override
	protected void doPost(HttpServletRequest request,IOException {
		response.setContentType("text/html;charset=utf-8");
		String action=request.getParameter("action");
		if("checkUserName".equals(action)){
			this.checkUserName(request,response);
		}else if("ejld".equals(action)){
			this.ejld(request,response);
		}
		
	}
	
	/**
	 * 验证用户名
	 */
	private void checkUserName(HttpServletRequest request,IOException {
		PrintWriter out=response.getWriter();
		String userName=request.getParameter("userName");
		JSONObject resultJson=new JSONObject();
		if("jack".equals(userName)){
			resultJson.put("exist",true);
		}else{
			resultJson.put("exist",false);
		}
		out.println(resultJson);
		out.flush();
		out.close();
	}
	/*
	 * 二级联动
	 */
	private void ejld(HttpServletRequest request,IOException {
		PrintWriter out=response.getWriter();
		String shengId=request.getParameter("shengId");
		JSONObject resultJson=new JSONObject();
		JSONArray jsonArray=new JSONArray();
		JSONObject temp=null;
		switch(Integer.parseInt(shengId)){
			case 1:{
				temp=new JSONObject();temp.put("id",1);temp.put("text","南京");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",2);temp.put("text","南通");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",3);temp.put("text","泰兴");jsonArray.add(temp);
				break;
			}
			case 2:{
				temp=new JSONObject();temp.put("id",4);temp.put("text","济南");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",5);temp.put("text","烟台");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",6);temp.put("text","蓬莱");jsonArray.add(temp);
				break;
			}
			case 3:{
				temp=new JSONObject();temp.put("id",7);temp.put("text","杭州");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",8);temp.put("text","宁波");jsonArray.add(temp);
				temp=new JSONObject();temp.put("id",9);temp.put("text","温州");jsonArray.add(temp);
				break;
			}
		}
		resultJson.put("rows",jsonArray);
		out.println(resultJson);
		out.flush();
		out.close();
	}
	
}

配置的xml信息

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>AjaxJsonchap01</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
  <servlet-name>getAjaxInfoServlet</servlet-name>
  <servlet-class>com.ruanku.web.GetAjaxInfoServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>getAjaxInfoServlet</servlet-name>
  	<url-pattern>/getAjaxInfo</url-pattern>
  </servlet-mapping>
</web-app>

<1>判断登录名是否相同

checkUserName.jsp

<%@ 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">
	function checkUserName(){
		var userName=document.getElementById("userName").value;
		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+")");
				if(dataObj.exist){
					document.getElementById("tip").innerHTML="<img src='no.png'/>该用户名已经存在";
				}else{
					document.getElementById("tip").innerHTML="<img src='ok.png'/>该用户名可用";
				}
			}
		};
		xmlHttp.open("get","getAjaxInfo?action=checkUserName&userName="+userName,true);
		
	    xmlHttp.send();
	}
</script>
</head>
<body>
<table>
	<tr>
		<th>用户注册</th>
	</tr>
	<tr>
		<td>用户名：</td>
		<td><input type="text" id="userName" name="userName" onblur="checkUserName()"/><font id="tip"></font></td>
	</tr>
	<tr>
		<td>密码：</td>
		<td><input type="text" id="password" name="password"/></td>
	</tr>
	<tr>
		<td>确认密码：</td>
		<td><input type="text" id="password2" name="password2"/></td>
	</tr>
	<tr>
		<td><input type="submit" value="注册"/></td>
		<td><input type="button" value="重置"/></td>
	</tr>
</table>
</body>
</html>

二级联动

ejld.jsp

<%@ 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">
	function loadInfo(){
		var shengId=document.getElementById("sheng").value;
		shi.options.length=0;  // 删除所有市下拉框的选项
		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+")");
				for(var i=0;i<dataObj.rows.length;i++){
					var o=dataObj.rows[i];
					shi.options.add(new Option(o.text,o.id));
				}
			}
		};
		xmlHttp.open("get","getAjaxInfo?action=ejld&shengId="+shengId,true);
		
	    xmlHttp.send();
	}
</script>
</head>
<body>
省：
<select id="sheng" onchange="loadInfo()">
	<option value="1">江苏省</option>
	<option value="2">山东省</option>
	<option value="3">浙江省</option>
</select>

市
<select id="shi">
</select>
</body>
</html>

原文链接：https://www.f2er.com/ajax/163994.html

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