Ajax的小案例
发布时间：2020-12-16 00:49:21 所属栏目：百科 来源：网络整理
导读：查询数据库客户是否存在 连接数据库 db.properties url=jdbc:mysql://localhost:3306/csdn?useUnicode=truecharacterEncoding=UTF-8user=rootpass=113driverClassName=com.mysql.jdbc.Driver 工具包DBConn.java package util;import java.io.IOExceptio
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查询数据库客户是否存在
连接数据库
db.properties url=jdbc:mysql://localhost:3306/csdn?useUnicode=true&characterEncoding=UTF-8
user=root
pass=113
driverClassName=com.mysql.jdbc.Driver
工具包DBConn.java
package util;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
public class DBConn {
private static Connection conn;
private DBConn() {
}
public static Connection getConn() {
if (conn == null) {
// 创建集合对象
Properties properties = new Properties();
try {
// 装载
properties.load(DBConn.class.getClassLoader()
.getResourceAsStream("db.properties"));
// 加载驱动程序
Class.forName(properties.getProperty("driverClassName"));
// 获取连接对象
conn = DriverManager.getConnection(
properties.getProperty("url"),properties.getProperty("user"),properties.getProperty("pass"));
conn.setAutoCommit(false);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return conn;
}
/**
* 单个数据的增加更新删除的事务处理
* @param sql
* @param params
* @param pstmt
*/
public static void update(String sql,Object params[],PreparedStatement pstmt) {
try {
pstmt = getConn().prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
pstmt.setObject(i + 1,params[i]);
}
pstmt.executeUpdate();
conn.commit();
} catch (Exception e) {
try {
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
e.printStackTrace();
} finally {
release(null,pstmt);
}
}
public static void release(ResultSet rs,PreparedStatement pstmt) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
读取数据库的信息 UserDomian.java package www.csdn.net.user.domian;
public class UserDomian {
private Integer id;
private String name;
private String pass;
public UserDomian() {
// TODO Auto-generated constructor stub
}
public UserDomian(Integer id,String name,String pass) {
super();
this.id = id;
this.name = name;
this.pass = pass;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
}
@Override
public String toString() {
return "UserDomian [id=" + id + ",name=" + name + ",pass=" + pass + "]";
}
}
UserDo.java package www.csdn.net.user.dao;
import java.util.List;
import www.csdn.net.user.domian.UserDomian;
public interface UserDo {
void insert(UserDomian entity) throws Exception;
void update(UserDomian entity) throws Exception;
void delete(UserDomian entity) throws Exception;
void deleteById(Integer id) throws Exception;
List<UserDomian> findAll() throws Exception;
UserDomian findById(Integer id) throws Exception;
/**
* 用户登录验证
*/
UserDomian checkLogin(String name,String pass) throws Exception;
/**
* 批量删除操作
*/
void deletes(Integer ids[]) throws Exception;
/**
* 分页处理
*/
List<UserDomian> findNowPageInfo(int nowpage) throws Exception;
/**
* 总页
*/
Integer getCountPage() throws Exception;
/**
* 判断用户信息是否存在
*/
boolean checkName(String name) throws Exception;
}
实现接口的类UserDoImpl.java package www.csdn.net.user.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import util.DBConn;
import www.csdn.net.user.dao.UserDo;
import www.csdn.net.user.domian.UserDomian;
public class UserDoImpl implements UserDo {
private Connection conn;
private PreparedStatement pstmt;
private ResultSet rs;
final int PAGESIZE = 10;
@Override
public void insert(UserDomian entity) throws Exception {
String sql = "insert into user (name,pass) values(?,?)";
DBConn.update(sql,new Object[] { entity.getName(),entity.getPass() },pstmt);
}
@Override
public void update(UserDomian entity) throws Exception {
String sql = "update user set name=?,pass=? where id=?";
DBConn.update(sql,entity.getPass(),entity.getId() },pstmt);
}
@Override
public void delete(UserDomian entity) throws Exception {
String sql = "delete from user where id=?";
DBConn.update(sql,new Object[] { entity.getId() },pstmt);
}
@Override
public void deleteById(Integer id) throws Exception {
String sql = "delete from user where id=?";
DBConn.update(sql,new Object[] { id },pstmt);
}
@Override
public List<UserDomian> findAll() throws Exception {
List<UserDomian> entities = new ArrayList<UserDomian>();
String sql = "select id,name,pass from user ";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
UserDomian entity = new UserDomian();
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
entities.add(entity);
}
return entities;
}
@Override
public UserDomian findById(Integer id) throws Exception {
UserDomian entity = null;
String sql = "select id,pass from user where id=?";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
int index = 1;
pstmt.setInt(index++,id);
rs = pstmt.executeQuery();
if (rs.next()) {
entity = new UserDomian();
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
}
return entity;
}
@Override
public UserDomian checkLogin(String name,String pass) throws Exception {
UserDomian entity = null;
String sql = "select id,pass from user where name=? and pass=?";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
int index = 1;
pstmt.setString(index++,name);
pstmt.setString(index++,pass);
rs = pstmt.executeQuery();
if (rs.next()) {
entity = new UserDomian();
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
}
return entity;
}
@Override
public void deletes(Integer[] ids) throws Exception {
conn = DBConn.getConn();
try {
for (int i = 0; i < ids.length; i++) {
String sql = "delete from user where id=?";
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1,ids[i]);
pstmt.executeUpdate();
// pstmt.addBatch();
}
// pstmt.executeBatch();
conn.commit();
} catch (Exception e) {
conn.rollback();
e.printStackTrace();
}
}
@Override
public List<UserDomian> findNowPageInfo(int nowpage) throws Exception {
List<UserDomian> entities = new ArrayList<UserDomian>();
String sql = "select id,pass from user limit ?,?";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
int index = 1;
pstmt.setInt(index++,(nowpage - 1) * PAGESIZE);
pstmt.setInt(index++,PAGESIZE);
rs = pstmt.executeQuery();
while (rs.next()) {
UserDomian entity = new UserDomian();
entity.setId(rs.getInt("id"));
entity.setName(rs.getString("name"));
entity.setPass(rs.getString("pass"));
entities.add(entity);
}
return entities;
}
// 总页数
@Override
public Integer getCountPage() throws Exception {
String sql = "select count(*) as c from user";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
int countsize = rs.getInt("c");
return countsize % PAGESIZE == 0 ? countsize / PAGESIZE : countsize
/ PAGESIZE + 1;
}
return null;
}
@Override
public boolean checkName(String name) throws Exception {
boolean flag = false;
String sql = "select id,pass from user where name=?";
conn = DBConn.getConn();
pstmt = conn.prepareStatement(sql);
int index = 1;
pstmt.setString(index++,name);
rs = pstmt.executeQuery();
if (rs.next()) {
flag = true;
}
return flag;
}
}
验证码RandomImage .java package img;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;
/**
* 验证码
* @author yanmei
*
*/
public class RandomImage {
private final static int W=80;
private final static int H=30;
public static BufferedImage createImage(){
//创建图片
BufferedImage image=new BufferedImage(W,H,BufferedImage.TYPE_INT_RGB);
//得到图形绘制的对象
Graphics g=image.getGraphics();
//设置背景颜色
setBackGroud(g);
//设置边框
setBorder(g);
//绘制内容
drawContent(g);
//绘制干扰线
drawDisturbline(g);
return image;
}
private static void drawDisturbline(Graphics g) {
g.setColor(Color.blue);
Random r=new Random();
for (int i = 0; i < 4; i++) {
int x1 = r.nextInt(W);
int y1 = r.nextInt(H);
int x2 = r.nextInt(W);
int y2 = r.nextInt(H);
g.drawLine(x1,y1,x2,y2);
}
}
private static void drawContent(Graphics g) {
// TODO Auto-generated method stub
//字节资源
String re = "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";
//获取字符的长度
int length=re.length();
//随机操作对象
Random r=new Random();
//存储字符的对象
StringBuffer sb=new StringBuffer();
for (int i = 0; i < 4; i++) {
//随机产生数字
int index=r.nextInt(length);
//获取字符
char c=re.charAt(index);
sb.append(c);
}
g.setColor(Color.black);
g.drawString(sb.toString(),20,20);
}
private static void setBorder(Graphics g) {
g.setColor(Color.black);
g.drawRect(0,W-2,H-2);
}
private static void setBackGroud(Graphics g) {
// 绘制矩形
g.setColor(Color.yellow);
g.fillRect(0,W,H);
}
}
package www.csdn.net.ajax.servlet;
import java.awt.Color;
import java.awt.Graphics;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import img.RandomImage;
public class ImageServlet extends HttpServlet {
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {
//禁止浏览器缓存数据
response.setHeader("expires","0");
response.setHeader("Cache-Control","no-cache");
response.setHeader("Pragma","no-cache");
//1.通知浏览器以图片的方式打开数据
response.setContentType("image/jpeg");
//把图片显示给浏览器
ImageIO.write(RandomImage.createImage(),"jpeg",response.getOutputStream());
}
public void doPost(HttpServletRequest request,IOException {
this.doGet(request,response);
}
}
login.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<!-- 引入js文件 -->
<script type="text/javascript" >
//当窗体加载完毕后触发该函数
window.onload = function(){
//获取name输入框的Dom对象
var inputName = document.getElementById("uname");
//注册事件
inputName.onblur= checkName;
};
function checkName(){
var name = this.value;
//1.第一步获取XMLHttpRequest对象
var xmlHttp = getXMLHttp();
//2. 第二步：打开请求
xmlHttp.open("GET","./checkName.do?name="+name+"&oper=checkName");
//3.第三步：发送请求
xmlHttp.send(null);//checkName.do
//4.第四步：函数处理
xmlHttp.onreadystatechange= processProgram;
}
function processProgram(){
//判断是否处理完成，响应的是否正常
//alert("22222222222222222222");
if(this.readyState==4&&this.status==200){
//服务器端响应过来的文本
var content = this.responseText;
//alert("---"+content);
//获取显示文本的span,Dom节点对象
var msgDom = document.getElementById("msg");
//清除操作
var childNodes = msgDom.childNodes;
for(var i=0;i<childNodes.length;i++){
//删除所有的孩子节点
msgDom.removeChild(childNodes[i]);
}
//创建一个文本节点对象
var textDom =document.createTextNode(content);
//在显示文本的span，Dom节点中添加textDom的孩子节点
msgDom.appendChild(textDom);
}
}
function getXMLHttp() {
// 第一步：声明返回值
var xmlHttp;
// 第二步：实例化xmlHttp对象
try {
// firefox Opera等
xmlHttp = new XMLHttpRequest();
} catch (e) {
try {
// IE浏览器
xmlHttp = new ActiveXObject("MSXML2.XMLHTTP5.0");
} catch (ex) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}
</script>
</head>
<body>
<div align="center">
<form action="./login.action" method="post">
<table border="1px" cellpadding="0" cellspacing="0">
<tr>
<td>用户名:</td>
<td><input type="text" name="name" id="uname"/></td>
<td><span id="msg"></span></td>
</tr>
<tr>
<td>密码:</td>
<td colspan="2"><input type="password" name="pass" /></td>
</tr>
<tr>
<td>验证码:</td>
<td><input type="text" name="code" /></td>
<td><img alt="验证码" src="./servlet/ImageServlet"></td>
</tr>
<tr>
<td colspan="3" align="center"><input type="reset" value="重置" />
<input type="submit" value="登录" /></td>
</tr>
</table>
</form>
</div>
</body>
</html>
web.xml<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
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_3_0.xsd">
<display-name></display-name>
<servlet>
<servlet-name>AjaxServlet</servlet-name>
<servlet-class>www.csdn.net.ajax.servlet.AjaxServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>www.csdn.net.ajax.servlet.ImageServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>AdminServlet</servlet-name>
<servlet-class>www.csdn.net.ajax.servlet.AdminServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AjaxServlet</servlet-name>
<url-pattern>/ajaxServlet.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>AdminServlet</servlet-name>
<url-pattern>/checkName.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/servlet/ImageServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
package www.csdn.net.ajax.servlet;
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 www.csdn.net.user.dao.UserDo;
import www.csdn.net.user.dao.impl.UserDoImpl;
public class AdminServlet extends HttpServlet {
private UserDo userDo=new UserDoImpl();
public void doGet(HttpServletRequest request,IOException {
String oper = request.getParameter("oper");
if ("checkName".equals(oper))
// 验证用户操作
checkName(request,response);
// System.out.println(oper);
}
public void checkName(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException {
String name = request.getParameter("name");
boolean flag=false;
try {
flag=userDo.checkName(name);
} catch (Exception e) {
e.printStackTrace();
}
//设置响应
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
if (flag) {
out.write("用户名被占用");
}else{
out.write("用户名可用");
}
//System.out.println("----------------------");
out.flush();
out.close();
}
public void doPost(HttpServletRequest request,IOException {
this.doGet(request,response);
}
}
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