20160406javaweb 之JDBC简单案例-白红宇

20160406javaweb 之JDBC简单案例

阅读量：6959 次

发布时间：2019-06-27

本文共 20394 字，大约阅读时间需要 67 分钟。

，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;}@Overridepublic 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"%>我的网站
     
     
      欢迎回来！${sessionScope.user.username }
      注销
     
     
      游客，欢迎你！
      注册|
      登录

<%@ 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" %>
     
      我的网站_登录
      
      ${msg }
      
       
                                            用户名：                               "/>                 
                                    密码：                                     
                                                        
           
             checked="checked" 
            />记住用户名

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>    <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> ${msg }
     
      我的网站_注册
      
       
                                       用户名：                                
         
                                密码：                                
         
                                确认密码：                                
         
                                昵称：                                
         
                                邮箱                                
         
                                验证码：