本文实现一个简单的java web项目功能---登录注册，目的是对前一段做的学习做个总结，以后有需要的话也可以直接拿来改改就能用，仅此。
版权声明：欢迎转载，转载请注明出处，谢谢！（如有侵权之处，也请联系修改或删除！）
1.实现效果如下：
1.1登录：
登录.png
1.2注册：
注册.png
2.Eclipse 项目结构：
项目结构.png
3.具体实现：
3.1 数据库建表（user_info）：
表名为：user_info
3.2 链接到数据库（JDBCUtil.java）
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBCUtil {
static String username = "yourusername";
static String password = "yourpassword";
static String driver = "com.mysql.jdbc.Driver";
static String url = "jdbc:mysql://localhost:3306/yoursqluame?useSSL=false";
//获取链接
public static Connection getConn(){
Connection conn = null;
try {
Class.forName(driver);
conn = DriverManager.getConnection(url,username, password);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
//释放链接
public static void release(Statement stmt,Connection conn){
if(stmt != null){
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
//重载释放链接
public static void release(ResultSet rs ,Statement stmt,Connection conn){
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(stmt != null){
try {
stmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
3.3 用户类（UserBean.java）
- login.jsp
package com.Bean;
public class UserBean {
private String userName;
private String password;
private String userEmail;
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 getUserEmail() {
return userEmail;
}
public void setUserEmail(String userEmail) {
this.userEmail = userEmail;
}
public UserBean(){
}
public UserBean(String userName,String password,String userEmail){
this.userName = userName;
this.password = password;
this.userEmail = userEmail;
}
}
3.4 Login与Register的jsp编写（login.jsp&®ister.jsp）
- login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>登录</title>
<script type="text/javascript">
function login(){
var th = document.form1;
if(th.email.value==""){
alert("Email Can't Be Bull");
th.email.focus();
return;
}
if(th.password.value==""){
alert("Password Can't Be Null");
th.password.focus();
return;
}
th.action="<%=path%>/LoginServlet";
th.submit();
}
</script>
<script type="text/javascript">
function change() {
var img = document.getElementById("verify");
img.src = "VerifyCodeServlet?a=" + new Date().getTime();
}
</script>
</head>
<body>
<div align="center">
<form name="form1" action="" method="post">
<table>
<tr>
<td>邮箱:</td>
<td><input name="email"></td>
</tr>
<tr>
<td>密码:</td>
<td><input name="password" type="password"></td>
</tr>
<tr>
<td>验证码：</td>
<td><input type="text" name="verifycode"></td>
<td><a href="javascript:change()"></a></td>
</tr>
<tr>
<td><input type="button" value="登录" onclick="login()"></td>
<td><input type="button" value="注册" onclick="javascript:location.href='register.jsp'">
</tr>
<tr>${msg}</tr>
</table>
</form>
</div>
</body>
</html>
- register.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Register</title>
<script type="text/javascript">
function register(){
var th = document.form1;
if(th.userName.value==""){
alert("UserName Can't Be Null");
th.userName.focus();
return;
}
if(th.email.value==""){
alert("Email Can't Be Null");
th.email.focus();
return;
}
if(th.password.value==""){
alert("Password Can't Be Null");
th.password.focus();
return;
}
if(th.password.value != th.psw.value){
alert("The Two Passwords Don't Match!");
th.psw.focus();
return;
}
th.action="<%=path%>/RegisterServlet";
th.submit();
}
</script>
</head>
<body>
<div align="center">
<form name="form1" action="" method="post">
<table>
<tr>
<td>UserName:</td>
<td><input name="userName"></td>
</tr>
<tr>
<td>Email:</td>
<td><input name="email"></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td>ConfirmPassword:</td>
<td><input type="password" name="psw"></td>
</tr>
<tr>
<td><input type="button" value="注册" onclick="register()"></td>
<td><input type="button" value="返回"
onclick="javascript:location.href='login.jsp'">
</tr>
<tr>${msg}</tr>
</table>
</form>
</div>
</body>
</html>
- welcome.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Welcome</title>
</head>
<body>
Welcome ${userName}
</body>
</html>
3.5 Servlet以及Dao层的实现
-LoginServlet.java
package com.Servlet;
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 com.Dao.UserDao;
/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String email = request.getParameter("email");
String password = request.getParameter("password");
String verifyc = request.getParameter("verifycode");
String svc =(String) request.getSession().getAttribute("sessionverify");
if(!svc.equalsIgnoreCase(verifyc)){
request.setAttribute("msg", "验证码错误！");
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
String userName = new UserDao().login(email,password);
if(userName == null){
request.setAttribute("msg", "用户名或密码错误！");
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}else{
request.setAttribute("userName", userName);
request.getRequestDispatcher("/welcome.jsp").forward(request, response);
return;
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
-RegisterServlet.java
package com.Servlet;
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 com.Bean.UserBean;
import com.Dao.UserDao;
/**
* Servlet implementation class RegisterServlet
*/
@WebServlet("/RegisterServlet")
public class RegisterServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public RegisterServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String userName = request.getParameter("userName");
String email = request.getParameter("email");
String password = request.getParameter("password");
boolean flag = new UserDao().checkEmail(email);
if(flag){
request.setAttribute("msg", "此邮箱已被注册！");
request.getRequestDispatcher("register.jsp").forward(request, response);
return;
}else{
new UserDao().register(userName,email,password);
request.setAttribute("msg", "欢迎您"+userName+",注册成功！");
request.getRequestDispatcher("login.jsp").forward(request, response);
return;
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
- UserDao.java
package com.Dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import com.Bean.UserBean;
import com.JDBCUtil.JDBCUtil;
public class UserDao {
//登录检测
public String login(String email, String password) {
// TODO Auto-generated method stub
String username = null;
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn =JDBCUtil.getConn();
String sql = "select user_name from user_info where user_email=? and user_password=?;";
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, email);
pstmt.setString(2, password);
rs = pstmt.executeQuery();
while(rs.next()){
username = rs.getString("user_name");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JDBCUtil.release(rs, pstmt, conn);
}
return username;
}
//检测邮箱是否已使用
public boolean checkEmail(String email) {
// TODO Auto-generated method stub
boolean flag = false;
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn = JDBCUtil.getConn();
String sql = "select * from user_info where user_email =?";
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, email);
rs = pstmt.executeQuery();
while(rs.next()){
flag = true;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JDBCUtil.release(rs, pstmt, conn);
}
return flag;
}
//注册用户
public void register(String userName,String email,String password) {
// TODO Auto-generated method stub
Connection conn = null;
PreparedStatement pstmt = null;
try {
conn = JDBCUtil.getConn();
String sql = "insert into user_info values("+userName+","+email+","+password+");";
pstmt = conn.prepareStatement(sql);
pstmt.executeUpdate(sql);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
JDBCUtil.release(pstmt, conn);
}
}
}
- VerifyCodeServlet.java
package com.Servlet;
import java.awt.image.BufferedImage;
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 com.Dao.VerifyCode;
/**
* Servlet implementation class VerifyCodeServlet
*/
@WebServlet("/VerifyCodeServlet")
public class VerifyCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public VerifyCodeServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
VerifyCode vc = new VerifyCode();
BufferedImage image = vc.getImage(85,23);
request.getSession().setAttribute("sessionverify", vc.getText());
VerifyCode.output(image, response.getOutputStream());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
- VerifyCode.java
package com.Dao;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
public class VerifyCode {
public static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8',
'9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
public static Random random = new Random();
public String getRandomString() {
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < 4; i++) {
buffer.append(CHARS[random.nextInt(CHARS.length)]);
}
return buffer.toString();
}
public Color getRandomColor() {
return new Color(random.nextInt(255), random.nextInt(255), random
.nextInt(255));
}
public Color getReverseColor(Color c) {
return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c
.getBlue());
}
String text = getRandomString();
public String getText() {
return text;
}
public BufferedImage getImage(int width,int height ){
Color color = getRandomColor();
Color reverse = getReverseColor(color);
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 20));
g.setColor(color);
g.fillRect(0, 0, width, height);
g.setColor(reverse);
g.drawString(text, 10, 22);
for (int i = 0, n = random.nextInt(80); i < n; i++) {
g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
}
return bi;
}
public static void output(BufferedImage image, OutputStream out) throws IOException{
ImageIO.write(image, "JPEG", out);
}
}
3.6 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>Blog_Demo</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
*说明：
1.数据库链接需要导入对应的jar包--mysql-connector-java-5.1.43-bin.jar。
2.直接粘贴复制，若出现中文变为乱码的情况，请转换项目字符格式或手动更改即可。
（* 第一次写文章，排版有可能不是很好理解，有什么建议欢迎指出！谢谢！）
