用MVC开发模式实现servlet简单的登录功能（带图片验证码）
2017-09-17 16:25
561 查看
一
首先需要链接数据库的jar包 mysql-connector-java-5.0.4-bin.jar
二
用到的工具类
验证码图片的工具类
package com.yinhe.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class DbOperation {
protected Connection conn;
protected PreparedStatement ps;
protected ResultSet rs;
private final String uname="root";
private final String psw="root";
//获取数据库链接
public void getConn(){
try {
//加载驱动
Class.forName("com.mysql.jdbc.Driver");
//获取链接
conn = DriverManager.getConnection(
"jdbc:mysql:///test",uname,psw);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//关闭
public void closeAll(){
try {
if(conn!=null){
conn.close();
}
if(ps!=null){
ps.close();
}
if(rs!=null){
rs.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//更新 Object... 会把传过来的任意个object类型的变量封装成一个数组
public void extUpdate(String sql, Object... obj){
try {
ps=conn.prepareStatement(sql);
for(int i=0;i<obj.length;i++){
ps.setObject(i+1, obj[i]);
}
ps.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//查询
public void extQuery(String sql, Object... obj){
try {
ps=conn.prepareStatement(sql);
for(int i=0;i<obj.length;i++){
ps.setObject(i+1, obj[i]);
}
rs=ps.executeQuery();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}封装类User
package com.yinhe.vo;
public class User {
private int uid;
private String username;
private String psw;
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPsw() {
return psw;
}
public void setPsw(String psw) {
this.psw = psw;
}
public User(String username, String psw) {
super();
this.username = username;
this.psw = psw;
}
}
前台需要的登录页面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<body>
<form action="login" method="post">
username:<input name="username" type="text"> <br>password:<input
name="psw" type="text"> <br>yanzhengma:<input name="yzm"
type="text"> <img src="checkCode" alt="" id="codeImg"
style="width: 80px; height: 30px; border: 1px
a14c
solid black;" /> <a
href="javascript:;"
onclick="document.getElementById('codeImg').src = 'checkCode?'+(new Date()).getTime()">换一张</a>
<span id="codemsg" style="color: red; font-size: 20px;">${message}</span>
<br><input type="submit" value="submit">
</form>
</body>
</html>
controller层
package com.yinhe.controller;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.yinhe.service.LoginService;
import com.yinhe.service.serviceImpl.LoginServiceImpl;
import com.yinhe.vo.User;
public class LoginServlet extends HttpServlet {
private LoginService ls = new LoginServiceImpl();
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
//获取前台参数
String username=req.getParameter("username");
String psw = req.getParameter("psw");
String yzm = req.getParameter("yzm");
//
String yzmb = (String) req.getSession().getAttribute("code");
if (yzm.equals(yzmb)){
User user = new User(username,psw);
String count = ls.doLogin(user);
if (count.equals("0")){
req.setAttribute("message", "账户或密码错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
}
else if (count.equals("1")){
req.getSession().setAttribute("username", user.getUsername());
req.getRequestDispatcher("/main.jsp").forward(req, resp);
}
}
else{
req.setAttribute("message", "验证码错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
}
}
}
Dao层接口
package com.yinhe.dao;
import com.yinhe.vo.User;
public interface LoginDao {
public String doLogin(User user);
}
Dao代码
package com.yinhe.dao.daoImpl;
import java.sql.SQLException;
import com.yinhe.dao.LoginDao;
import com.yinhe.util.DbOperation;
import com.yinhe.vo.User;
public class LoginDaoImpl extends DbOperation implements LoginDao {
@Override
public String doLogin(User user) {
getConn();
String sql = "select count(*) from user where username=? and psw=?";
extQuery(sql, user.getUsername(),user.getPsw());
int count = 0;
try {
if(rs.next()){
count = rs.getInt(1);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
closeAll();
return count + "";
}
}
Service层接口
package com.yinhe.service;
import com.yinhe.vo.User;
public interface LoginService {
public String doLogin(User user);
}
Service层代码
package com.yinhe.service.serviceImpl;
import com.yinhe.dao.LoginDao;
import com.yinhe.dao.daoImpl.LoginDaoImpl;
import com.yinhe.service.LoginService;
import com.yinhe.vo.User;
public class LoginServiceImpl implements LoginService {
private LoginDao ld = new LoginDaoImpl();
@Override
public String doLogin(User user) {
return ld.doLogin(user);
}
}
首先需要链接数据库的jar包 mysql-connector-java-5.0.4-bin.jar
二
用到的工具类
验证码图片的工具类
package com.yinhe.util;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
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;
public class CodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String codes="abcdefghijklmnopqrstuvwxyz";
BufferedImage img=new BufferedImage(80,30,BufferedImage.TYPE_3BYTE_BGR);
Graphics g=img.getGraphics();
//填充图片
g.setColor(new Color(255,255,255));
g.fillRect(0, 0, 80, 30);
//画入五个随机数
Random rm=new Random();
StringBuffer sb=new StringBuffer();
for(int i=0;i<5;i++){
int index=rm.nextInt(codes.length());
char code=codes.charAt(index);
g.setColor(new Color(rm.nextInt(256),rm.nextInt(256),rm.nextInt(256)));
g.setFont(new Font("宋体", Font.BOLD, 25));
g.drawString(code+"", 2+15*i, 22);
sb.append(code);
}
//画干扰线
for(int i=0;i<10;i++){
g.setColor(new Color(rm.nextInt(256),rm.nextInt(256),rm.nextInt(256)));
g.drawLine(rm.nextInt(100), rm.nextInt(50), rm.nextInt(100), rm.nextInt(50));
}
//将验证码图片回写给浏览器
response.setContentType("image/jpeg;charset=utf-8");
OutputStream out=response.getOutputStream();
ImageIO.write(img, "jpeg", out);
//将随机字符串保存在session中
request.getSession().setAttribute("code", sb.toString());
}
}链接数据库的工具类package com.yinhe.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class DbOperation {
protected Connection conn;
protected PreparedStatement ps;
protected ResultSet rs;
private final String uname="root";
private final String psw="root";
//获取数据库链接
public void getConn(){
try {
//加载驱动
Class.forName("com.mysql.jdbc.Driver");
//获取链接
conn = DriverManager.getConnection(
"jdbc:mysql:///test",uname,psw);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//关闭
public void closeAll(){
try {
if(conn!=null){
conn.close();
}
if(ps!=null){
ps.close();
}
if(rs!=null){
rs.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//更新 Object... 会把传过来的任意个object类型的变量封装成一个数组
public void extUpdate(String sql, Object... obj){
try {
ps=conn.prepareStatement(sql);
for(int i=0;i<obj.length;i++){
ps.setObject(i+1, obj[i]);
}
ps.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//查询
public void extQuery(String sql, Object... obj){
try {
ps=conn.prepareStatement(sql);
for(int i=0;i<obj.length;i++){
ps.setObject(i+1, obj[i]);
}
rs=ps.executeQuery();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}封装类User
package com.yinhe.vo;
public class User {
private int uid;
private String username;
private String psw;
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPsw() {
return psw;
}
public void setPsw(String psw) {
this.psw = psw;
}
public User(String username, String psw) {
super();
this.username = username;
this.psw = psw;
}
}
前台需要的登录页面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<body>
<form action="login" method="post">
username:<input name="username" type="text"> <br>password:<input
name="psw" type="text"> <br>yanzhengma:<input name="yzm"
type="text"> <img src="checkCode" alt="" id="codeImg"
style="width: 80px; height: 30px; border: 1px
a14c
solid black;" /> <a
href="javascript:;"
onclick="document.getElementById('codeImg').src = 'checkCode?'+(new Date()).getTime()">换一张</a>
<span id="codemsg" style="color: red; font-size: 20px;">${message}</span>
<br><input type="submit" value="submit">
</form>
</body>
</html>
controller层
package com.yinhe.controller;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.yinhe.service.LoginService;
import com.yinhe.service.serviceImpl.LoginServiceImpl;
import com.yinhe.vo.User;
public class LoginServlet extends HttpServlet {
private LoginService ls = new LoginServiceImpl();
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
//获取前台参数
String username=req.getParameter("username");
String psw = req.getParameter("psw");
String yzm = req.getParameter("yzm");
//
String yzmb = (String) req.getSession().getAttribute("code");
if (yzm.equals(yzmb)){
User user = new User(username,psw);
String count = ls.doLogin(user);
if (count.equals("0")){
req.setAttribute("message", "账户或密码错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
}
else if (count.equals("1")){
req.getSession().setAttribute("username", user.getUsername());
req.getRequestDispatcher("/main.jsp").forward(req, resp);
}
}
else{
req.setAttribute("message", "验证码错误");
req.getRequestDispatcher("/login.jsp").forward(req, resp);
}
}
}
Dao层接口
package com.yinhe.dao;
import com.yinhe.vo.User;
public interface LoginDao {
public String doLogin(User user);
}
Dao代码
package com.yinhe.dao.daoImpl;
import java.sql.SQLException;
import com.yinhe.dao.LoginDao;
import com.yinhe.util.DbOperation;
import com.yinhe.vo.User;
public class LoginDaoImpl extends DbOperation implements LoginDao {
@Override
public String doLogin(User user) {
getConn();
String sql = "select count(*) from user where username=? and psw=?";
extQuery(sql, user.getUsername(),user.getPsw());
int count = 0;
try {
if(rs.next()){
count = rs.getInt(1);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
closeAll();
return count + "";
}
}
Service层接口
package com.yinhe.service;
import com.yinhe.vo.User;
public interface LoginService {
public String doLogin(User user);
}
Service层代码
package com.yinhe.service.serviceImpl;
import com.yinhe.dao.LoginDao;
import com.yinhe.dao.daoImpl.LoginDaoImpl;
import com.yinhe.service.LoginService;
import com.yinhe.vo.User;
public class LoginServiceImpl implements LoginService {
private LoginDao ld = new LoginDaoImpl();
@Override
public String doLogin(User user) {
return ld.doLogin(user);
}
}
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