[置顶]关于我的JAVA开发——AJAX案例：用AJAX实现级联菜单功能（中）

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[置顶]关于我的JAVA开发——AJAX案例：用AJAX实现级联菜单功能（中）

2013年08月30日 ⁄ 综合 ⁄ 共 7071字 ⁄ 字号小中大 ⁄ 评论关闭

用AJAX实现级联菜单功能

BaseDao.java

package com.LJ.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class BaseDao{
	/**
	 * 产生一个servletID
	 */
	private static final long serialVersionUID = -3005086949118705373L;
	//定义各种数据库的链接常量
	private static final String 

DRIVER_NAME="com.microsoft.jdbc.sqlserver.SQLServerDriver";
	private static final String 

DRIVER_URL="jdbc:sqlserver://localhost:1433;DatabaseName=computer";
	private static final String DB_USER_NAME="sa";
	private static final String DB_USER_PWD="sa";
	
	
	//获取数据库链接对象
	public static Connection getConn() throws ClassNotFoundException, 

SQLException{
		Class.forName(DRIVER_NAME);
		Connection conn = DriverManager.getConnection(DRIVER_URL, 

DB_USER_NAME,
				DB_USER_PWD);
		return conn;
	}
	
	
//	public static Connection getConn() throws NamingException, SQLException{
//	    //初始化应用上下文
//		InitialContext ic = new InitialContext(); 
//		//java:comp/env为固定的前缀，jdbc/empdatabase1则为配置的数据源的名称
//		DataSource conn = (DataSource) ic.lookup

("java:comp/env/jdbc/news"); 
//		return conn.getConnection();
//	}
	
	
	//释放数据库资源
	public static void CloseAll(Connection conn, PreparedStatement ps,
			ResultSet rs) {
		if (rs != null)
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		if (ps != null)
			try {
				ps.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		if (conn != null)
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
	}
}

ComputereDao.java

package com.LJ.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.LJ.entity.COMPUTER;

public class ComputerDao extends BaseDao {

	private static Connection conn = null; // 保存数据库连接
	private static PreparedStatement ps = null; // 用于执行SQL语句
	private static ResultSet rs = null; // 用于保存查询结果集

	// 增加一个方法向数据库查询出数据，并以集合的方式返回
	public List<COMPUTER> getAllPoll(String locus){
		List<COMPUTER> list = new ArrayList<COMPUTER>();
		try {
			conn = BaseDao.getConn();
			String sql = " select brand from computero where locus = 

? ";
			ps = conn.prepareStatement(sql);
			ps.setString(1, locus);
			rs = ps.executeQuery();
			while(rs.next()){
				COMPUTER computer = new COMPUTER();
				computer.setBrand(rs.getString("brand"));
				list.add(computer);
			}
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			BaseDao.CloseAll(conn, ps, rs);
		}
		return list;
	}
}

COMPUTER.java

package com.LJ.entity;

public class COMPUTER {
	private int id;
	private String brand;
	private String locus;
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public String getLocus() {
		return locus;
	}
	public void setLocus(String locus) {
		this.locus = locus;
	}
	
	public COMPUTER(int id, String brand, String locus) {
		super();
		this.id = id;
		this.brand = brand;
		this.locus = locus;
	}
	public COMPUTER() {
		super();
	}
	
}

MessageServlet.java

package com.LJ.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

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

import com.LJ.dao.ComputerDao;
import com.LJ.entity.COMPUTER;

public class MessageServlet extends HttpServlet {

	/**
	 * 增加对servlet的ID处理
	 */
	private static final long serialVersionUID = 2315859662727740974L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse 

response)
			throws ServletException, IOException {
		//设置接收信息的字符集
		request.setCharacterEncoding("UTF-8");
		//接收浏览器端提交的信息
		String locus = request.getParameter("locus");
		//设置输出信息的格式及字符
		response.setContentType("text/xml;charset=UTF-8");
		response.setHeader("Cache-Control","no-cache");
		//创建输出流
		PrintWriter out = response.getWriter();
		//依据结果输出不同的数据信息
		out.print("<response>");
		//查找该品牌具体型号
		ComputerDao computerDao = new ComputerDao();
		List<COMPUTER> list = computerDao.getAllPoll(locus);
		for (int i = 0; i < list.size(); i++) {
			COMPUTER computer = list.get(i);
			out.println("<res>"+ computer.getBrand() 

+"</res>");
		}
		out.println("</response>");
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse 

response)
			throws ServletException, IOException {
		//如果请求为dopost请求，则调用doget方法
		this.doGet(request, response);
	}
	
	
}

ComputerDaoTest.java

package com.LJ.test;

import java.util.List;

import com.LJ.dao.ComputerDao;
import com.LJ.entity.COMPUTER;

public class ComputerDaoTest {
	public static void main(String[] args) {
		ComputerDao computerDao = new ComputerDao();
		List<COMPUTER> list = computerDao.getAllPoll

("inside");
		for (int i = 0; i < list.size(); i++) {
			COMPUTER computer = list.get(i);
			 System.out.println(computer.getBrand());
		}
	}
}

joinMenu.js

//创建级联菜单函数
function showSubMenu(obj) {
	currentSort = document.getElementById(obj);
	currentSort.parentNode.style.display = "";
	sendRequest("messageServlet?locus=" + obj);
}

//发送请求函数
function sendRequest(url) {
	//调用创建XMLHttpReqeust对象的函数
	alert(url);
	createXMLHttpRequest();
	xmlHttpReq.open("GET", url, true);
	//调用回调函数(当状态发生改变时调用回调函数)
	xmlHttpReq.onreadystatechange = processResponse;
	//发送请求
	xmlHttpReq.send(null);
}

//创建XMLHttpRequest对象
function createXMLHttpRequest() {

	//创建XMLHttpRequest对象
	if (window.XMLHttpRequest) {
		//IE7,IE8,FireFox,Mozillar,Opera浏览器
		xmlHttpReq = new XMLHttpRequest();
		//当头的设置不是text/xml形式时，则要重新设置为text/xml
		if (xmlHttpReq.overrideMimeType) {
			xmlHttpReq.overrideMimeType("text/xml");
		}
	} else if (window.ActiveXObject) {
		//IE6,IE5,IE5.5,因为所有浏览器都是基于ActiveXObject所以放置在后面实现效

能会好些
		var activexName = [ "MSXML2.XMLHTTP.6.0", 

"MSXML2.XMLHTTP.5.0",
				"MSXML2.XMLHTTP.4.0", 

"MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
				"Miscrosoft.XMLHTTP" ];
		for ( var i = 0; i < activexName.length; i++) {
			try {
				xmlHttpReq = new ActiveXObject(activexName[i]);
				break;//一但创建成功就不需要再进行判断
			} catch (e) {
				//异常不需要处理	
			}
		}
	}
}
//处理返回信息函数
function processResponse() {
	if (xmlHttpReq.readyState == 4) {
		if (xmlHttpReq.status == 200) {
			updateMenu();
		} else {
			alert("响应异常");
		}
	}
}

function updateMenu() {
	var res = xmlHttpReq.responseXML.getElementsByTagName("res");
	var subMenu = "";
	for ( var i = 0; i < res.length; i++) {
		subMenu = subMenu + "  " + res[i].firstChild.data + 

"<br>"
	}
	currentSort.innerHTML = subMenu;
}

web.xml

<?xml version="1.0" 

encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
	
	<servlet>
		<servlet-name>messageServlet</servlet-name>
		<servlet-class>com.LJ.servlet.MessageServlet</servlet-

class>
	</servlet>
	<servlet-mapping>
		<servlet-name>messageServlet</servlet-name>
		<url-pattern>/messageServlet</url-pattern>
	</servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

index.jsp

<%@ page language="java" 

import="java.util.*" pageEncoding="UTF-8"%>
<html>
	<head>
		<title>使用AJAX实现省市联级效果</title>
	<script type="text/javascript" 

src="JS/joinMenu.js"></script>
	</head>
	<body>
		<table style="border-collapse: collapse" 

bordercolor="#111111"
			cellspacing="0" cellpadding="0" 

width="200" bgcolor="#f5efe7"
			border="0" align="center">
			<tr>
				<td align="center" 

height="20">
					笔记本品牌
				</td>
			</tr>
			<tr>
				<td align="center">
					<a onclick="showSubMenu('inside')

">国内品牌</a>
				</td>
			</tr>
			<tr style="display: none">
				<td id="inside" height="20" 

align="center"></td>
			</tr>
			<tr>
				<td align="center">
					<a onclick="showSubMenu('outside')

">国外品牌</a>
				</td>
			</tr>
			<tr style="display: none">
				<td id="outside" height="20" 

align="center"></td>
			</tr>
		</table>
	</body>
</html>

注意：别忘了导入数据库驱动类，在项目中的WEB-INFO ------> lib中，别忘了建立数据库，数据库名，表名，跟字段在图片中有体现。

【上篇】Linux内核实践之 —- 序列文件
【下篇】《Web信息架构：设计大型网站（第3版）》技术审校者序

作者: skippy

该日志由 skippy 于11年前发表在综合分类下，最后更新于 2013年08月30日.
转载请注明: [置顶]关于我的JAVA开发——AJAX案例：用AJAX实现级联菜单功能（中） | 学步园 +复制链接

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[置顶]关于我的JAVA开发——AJAX案例：用AJAX实现级联菜单功能（中）

BaseDao.java

作者: skippy

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