20160406javaweb 之JDBC简单案例
前几天写的user注册登录注销案例,没有用到数据库,现在做出改动,使用数据库存储信息:
一、首先我们需要建立一个数据库:
如下图:
创建数据库的代码如下:
-- 导出 database02 的数据库结构
CREATE DATABASE IF NOT EXISTS `database02` /*!40100 DEFAULT CHARACTER SET utf8 */;
USE `database02`; -- 导出 表 database02.users 结构
CREATE TABLE IF NOT EXISTS `users` (
`id` int(10) NOT NULL AUTO_INCREMENT,
`username` varchar(20) NOT NULL,
`password` varchar(50) NOT NULL,
`nickname` varchar(40) NOT NULL,
`email` varchar(50) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
二、创建包和类
1.创建一个接口
package com.dzq.dao; import com.dzq.domian.User; public interface UserDao { /**
* 根据用户名查找用户
* @param username 用户名
* @return 根据用户名找到的用户信息,如果没找到,返回null
*/
public User findUserByUserName(String username); /**
* 添加用户
* @param user 要添加用户信息的bean
*/
public void addUser(User user);
/**
* 根据用户名密码查找用户信息
* @param username 用户名
* @param password 密码
* @return 找到的用户,找不到返回null
*/
public User findUserByUNAndPWD(String username,String password);
}
2.创建操作数据库的工具类:
package com.dzq.util; import java.io.FileReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties; public class JDBCUtils { private static Properties prop=null; private JDBCUtils(){ } /**
* 静态代码块,加载数据库配置文件
*/
static{
try{
prop=new Properties();
prop.load(new FileReader(JDBCUtils.class.getClassLoader().getResource("config.properties").getPath()));
}catch(Exception e){
e.printStackTrace();
throw new RuntimeException();
}
} /**
* 获取连接
*/
public static Connection getConn() throws Exception{ Class.forName(prop.getProperty("driver"));
return DriverManager.getConnection(prop.getProperty("url"), prop.getProperty("user"), prop.getProperty("password"));
} /**
* 关闭连接
*/
public static void close(ResultSet rs,Statement stat,Connection conn){
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
rs=null;
}
}
if(stat!=null){
try {
stat.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
stat=null;
}
}
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
conn=null;
}
}
}
}
3.创建异常处理类
package com.dzq.exception; public class MsgException extends Exception {
public MsgException(){ } public MsgException(String msg){
super(msg);
}
}
4.创建javabean类
package com.dzq.domian; import java.io.Serializable; import com.dzq.exception.MsgException; public class User implements Serializable{
private int id;
private String username;
private String password;
private String password2;
private String nickname;
private String email; public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getPassword2() {
return password2;
}
public void setPassword2(String password2) {
this.password2 = password2;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
} public User(){ }
public User(String username, String password, String password2,
String nickname, String email) { this.username = username;
this.password = password;
this.password2 = password2;
this.nickname = nickname;
this.email = email;
}
@Override
public String toString() {
return username+":"+password;
}
public void checkValue() throws MsgException{
if(username==null||"".equals(username)){
throw new MsgException("用户名不能为空");
}
if(password==null||"".equals(password)){
throw new MsgException("密码不能为空");
}
if(password2==null||"".equals(password2)){
throw new MsgException("密码不能为空");
}
if(!password.equals(password2)){
throw new MsgException("两次密码输入不一致");
}
if(nickname==null||"".equals(nickname)){
throw new MsgException("昵称不能为空");
}
if(email==null||"".equals(email)){
throw new MsgException("邮箱不能为空");
}
} }
5.实现上述接口
package com.dzq.dao; import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement; import com.dzq.domian.User;
import com.dzq.util.JDBCUtils; public class MySqlUserDao implements UserDao{ @Override
public User findUserByUserName(String username) {
String sql="select * from users where username='"+username+"'";
Connection conn=null;
Statement stat=null;
ResultSet rs=null;
try {
conn=JDBCUtils.getConn();
stat=conn.createStatement();
rs=stat.executeQuery(sql);
if(rs.next()){
User user=new User();
user.setId(rs.getInt("id"));
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
user.setNickname(rs.getString("nickname"));
user.setEmail(rs.getString("email"));
return user;
}else{
return null;
}
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}finally{
JDBCUtils.close(rs, stat, conn);
}
} @Override
public void addUser(User user) {
String sql="insert into users values (null,'"+user.getUsername()+"','"+user.getPassword()+"','"+user.getNickname()+"','"+user.getEmail()+"')";
Connection conn=null;
Statement stat=null;
ResultSet rs=null;
try {
conn=JDBCUtils.getConn();
stat=conn.createStatement();
int count=stat.executeUpdate(sql); } catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}finally{
JDBCUtils.close(rs, stat, conn);
}
} @Override
public User findUserByUNAndPWD(String username, String password) {
String sql="select * from users where username='"+username+"'and password='"+password+"'";
Connection conn=null;
Statement stat=null;
ResultSet rs=null;
try {
conn=JDBCUtils.getConn();
stat=conn.createStatement();
rs=stat.executeQuery(sql);
if(rs.next()){
User user=new User();
user.setId(rs.getInt("id"));
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
user.setNickname(rs.getString("nickname"));
user.setEmail(rs.getString("email"));
return user;
}else{
return null;
}
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}finally{
JDBCUtils.close(rs, stat, conn);
}
} }
6.创建service类
package com.dzq.service; import com.dzq.dao.MySqlUserDao;
import com.dzq.dao.XmlUserDao;
import com.dzq.domian.User;
import com.dzq.exception.MsgException; public class UserService {
//private XmlUserDao dao=new XmlUserDao();
private MySqlUserDao dao=new MySqlUserDao();
/**
* 添加用户
* @param user
* @throws MsgException
*/
public void registUser(User user) throws MsgException{
if(dao.findUserByUserName(user.getUsername())!=null){
throw new MsgException("用户名已经存在");
}
dao.addUser(user);
}
/**
* 检查用户名是否正确
* @param username
* @param password
*/
public User isUser(String username,String password){
return dao.findUserByUNAndPWD(username, password); }
}
7.建立几个servlet
package com.dzq.web; import java.io.IOException;
import java.net.URLEncoder; import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import com.dzq.domian.User;
import com.dzq.service.UserService; @WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String username=request.getParameter("username");
String password=request.getParameter("password");
UserService service=new UserService();
User user=service.isUser(username, password);
if(user==null){
request.setAttribute("msg", "用户名或者密码错误");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}else{
request.getSession().setAttribute("user", user);
if("ok".equals(request.getParameter("remname"))){
Cookie remNameC=new Cookie("remname",URLEncoder.encode(user.getUsername(),"utf-8"));
remNameC.setPath(request.getContextPath());
remNameC.setMaxAge(3600*24*30);
response.addCookie(remNameC);
}else{
Cookie remNameC=new Cookie("remname","");
remNameC.setPath(request.getContextPath());
remNameC.setMaxAge(0);
response.addCookie(remNameC);
}
response.sendRedirect(request.getContextPath()+"/index.jsp");
}
} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
} }
package com.dzq.web; 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; @WebServlet("/LogOutServlet")
public class LogOutServlet extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
if(request.getSession(false)!=null&&request.getSession().getAttribute("user")!=null){
request.getSession().invalidate();
response.sendRedirect(request.getContextPath()+"/index.jsp");
}
} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
} }
package com.dzq.web; 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.apache.commons.beanutils.BeanUtils; import com.dzq.domian.User;
import com.dzq.exception.MsgException;
import com.dzq.service.UserService; @WebServlet("/RegistServlet")
public class RegistServlet extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
try {
UserService service=new UserService();
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
//1。检验验证码
String valistr=request.getParameter("valistr");
String valistr2=(String) request.getSession().getAttribute("valistr");
if(valistr==null||valistr2==null||!valistr.equals(valistr2)){
request.setAttribute("msg", "验证码不正确");
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}
//2.封装数据,校验数据
User user=new User();
BeanUtils.populate(user, request.getParameterMap());
user.checkValue();
service.registUser(user);
request.getSession().setAttribute("user", user);
response.getWriter().write("恭喜您注册成功,3秒回到主页");
response.setHeader("refresh", "3;url="+request.getContextPath()+"/index.jsp");
}catch(MsgException e){
request.setAttribute("msg",e.getMessage());
request.getRequestDispatcher("/regist.jsp").forward(request, response);
return;
}catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
//3.调用service方法添加用户 //4.提示注册成功,3秒跳转主页
} protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
} }
package com.dzq.web; import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random; import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; @WebServlet("/ValiImg")
public class ValiImg extends HttpServlet {
private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
response.setDateHeader("Expires", -1);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma","no-cache");
//1.在内存中构建一张图片
int height=30;
int width=120;
int xpyl=5;
int ypyl=22;
int bang=20;
BufferedImage img=new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
//2.获取图像上的画布
Graphics2D g=(Graphics2D) img.getGraphics();
//3.设置背景色
g.setColor(Color.LIGHT_GRAY);
g.fillRect(0, 0, width, height);
//4.设置边框
g.setColor(Color.BLUE);
g.drawRect(0, 0, width-2, height-2);
//5.画干扰线
for(int i=0;i<5;i++){
g.setColor(Color.RED);
g.drawLine(randNum(0, width), randNum(0, height), randNum(0, width), randNum(0, height));
}
//6.写字
String base = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
StringBuffer buffer=new StringBuffer(); for(int i=0;i<4;i++){
g.setColor(new Color(randNum(0, 255),randNum(0, 255),randNum(0, 255)));
g.setFont(new Font("黑体",Font.BOLD,bang));
int r=randNum(-45, 45);
g.rotate(1.0*r/180*Math.PI,xpyl+i*30, ypyl);
String s=base.charAt(randNum(0, base.length()-1))+"";
buffer.append(s);
g.drawString(s, xpyl+i*30, ypyl);
g.rotate(1.0*-r/180*Math.PI,xpyl+i*30, ypyl);
}
request.getSession().setAttribute("valistr", buffer.toString());
System.out.println(buffer.toString());
//将图片输出到浏览器
ImageIO.write(img, "jpg", response.getOutputStream()); }
private Random rand=new Random();
private int randNum(int begin,int end){ return rand.nextInt((end-begin)+begin); }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
8. jsp页面:
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<html>
<head>
</head>
<body>
<h1>我的网站</h1><hr>
<c:if test="${sessionScope.user!=null}">
欢迎回来!${sessionScope.user.username }<a href="${pageContext.request.contextPath }/LogOutServlet">注销</a>
</c:if> <c:if test="${sessionScope.user==null}">
游客,欢迎你!<a href="${pageContext.request.contextPath }/regist.jsp">注册</a>|<a href="${pageContext.request.contextPath }/login.jsp">登录</a>
</c:if>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@taglib uri="http://www.dzq.com/UserTag" prefix="UserTag" %>
<html>
<head> </head>
<body>
<div align="center">
<h1>我的网站_登录</h1><hr>
<font color="red">${msg }</font>
<form action="${pageContext.request.contextPath }/LoginServlet" method="post">
<table border="1">
<tr>
<td>用户名:</td> <td><input type="text" name="username" value="<UserTag:URLDecoder content="${cookie.remname.value }" encode="utf-8"/>"/></td>
</tr>
<tr>
<td>密码:</td>
<td><input type="password" name="password"/></td>
</tr>
<tr>
<td><input type="submit" value="登录"/></td>
<td><input type="checkbox" value="ok" name="remname"
<c:if test="${cookie.remname!=null }">
checked="checked"
</c:if>
/>记住用户名</td>
</tr>
</table>
</form>
</div>
</body>
</html>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<html>
<head>
<script type="text/javascript">
function changeImg(img){
img.src=img.src+"?time="+new Date().getTime();
}
</script>
</head>
<font color="red" >${msg }</font>
<body>
<div align="center">
<h1>我的网站_注册</h1>
<form action="${pageContext.request.contextPath }/RegistServlet" method="post">
<table border="1">
<tr>
<td>用户名:</td>
<td><input type="text" name="username" value="${param.username }"/></td>
<tr/>
<tr>
<td>密码:</td>
<td><input type="password" name="password" /></td>
<tr/>
<tr>
<td>确认密码:</td>
<td><input type="password" name="password2" /></td>
<tr/>
<tr>
<td>昵称:</td>
<td><input type="text" name="nickname" value="${param.nickname }"/></td>
<tr/>
<tr>
<td>邮箱</td>
<td><input type="email" name="email" value="${param.email }"/></td>
<tr/>
<tr>
<td>验证码:</td>
<td><input type="text" name="valistr" /></td>
<tr/>
<tr>
<td><input type="submit" value="注册"/></td>
<td><img src="${pageContext.request.contextPath }/ValiImg" style="cursor: pointer;" onclick="changeImg(this)"></td>
<tr/> </table>
</form>
</div>
</body>
</html>
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