采用Servlet+JDBC+MySQL+Jsp完成一个登陆注册界面
myEclipse for Spring2014
Navicat : 用来管理MySQL数据库
Firefox浏览器:用来展现并调试页面
第一步：先创建一个web项目工程，(涉及到从数据库抓取数据展现到浏览器项目的均为Web Project)取个名字吧：LoginDemo，简要步骤如下：
File-New-Web Project
然后在上面视图中点击两次“下一步”后进入如下页面，勾选generate web.xml....,则可以自动在WebRoot/WEB-INF下生成一个web.xml文件
如下是自动生成的web.xml文件的内容：
接下来我们创建一个servlet,取名为LoginServlet，处理用户登录，步骤如下：
File-New-Servlet
点击下一步
点击上图完成，则一个登录的servlet创建完成了，但此时web.xml里没有自动给我们配置servlet，它是以注释的形式体现出来，如下图示：
所以为了能在web.xml里面自动配置servlet,我们需要采取其它方法。
在创建项目时，我们选择Dynamic Web Project, 2.5版本的支持web.xml里面自动配置servlet,3.0的不支持。
选择Dynamic Web Project, 2.5版本后，web.xml自动生成了servlet配置，如下图：
导入访问数据库的jar包
好了，准备工作基本结束了，现在开始上菜了：
第二步，编写代码了。
1>Login.jsp:
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
登录
2>LoginFailed.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
登录失败，请返回重新登录
3>LoginSuccess.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
登录成功!!!!
4>zhuCe.jsp
<%@ page language="java" pageEncoding="utf-8"%>
<%@ page contentType="text/html;charset=utf-8"%>
<%
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html; charset=utf-8");
%>
注册:
5>zhuCeSuccess.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
注册成功!!!!
6>User.jsp
package com.user;
/*
* 用户登录类，定义基本属性，用户名和密码
*/
public class User {
private String username;
private String password;
public String getUsername(){
return this.username;
}
public void setUsername(String username){
this.username = username;
}
public String getPassword(){
return this.password;
}
public void setPassword(String password){
this.password = password;
}
}
7>DBDao.java
package com.dao;
import java.sql.*;
public class DBDao {
private static String USER = "root";
private static String PASSWORD = "123456";
private static String DB_URL = "jdbc:mysql://localhost:3306/logindemo";
private static String DB_DRIVER = "com.mysql.jdbc.Driver";
private static Connection connection = null;
//连接数据库
public static Connection getConnection(){
try {
Class.forName(DB_DRIVER);
connection = DriverManager.getConnection(DB_URL, USER, PASSWORD);
} catch (Exception e) {
System.out.println("数据库连接异常");
e.printStackTrace();
}
return connection;
}
public static void closeConnection(Connection connection){
if(connection != null){
try {
connection.close(); // 关闭数据库连接
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
8>UserDao.java
package com.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import com.user.User;
public class UserDao {
User user = null;
private String SQL = "";
public User login(String username, String password) {
SQL = "select * from UserPWD where username = ? and password = ?";
Connection connection = null;
PreparedStatement pstmt = null;
try {
connection = DBDao.getConnection();
pstmt = (PreparedStatement) connection.prepareStatement(SQL);
// 这里的意思将用户名和密码填到SQL语句的问号处
pstmt.setString(1, username);
pstmt.setString(2, password);
ResultSet rSet = (ResultSet) pstmt.executeQuery();//得到数据库的查询结果,一个数据集
// 判断结果集是否有效
if (rSet.next()) {
user = new User();
user.setUsername(rSet.getString("username"));
user.setPassword(rSet.getString("password"));
}
pstmt.close();
connection.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
DBDao.closeConnection(connection);
}
return user;
}
public int zhuCe(String username, String password) {
SQL = "insert into userpwd(username,password) values (?,?)";
int b=0;
Connection connection = null;
PreparedStatement pstmt = null;
try {
connection = DBDao.getConnection();
pstmt = connection.prepareStatement(SQL);
pstmt.setString(1, username);
pstmt.setString(2, password);
b=pstmt.executeUpdate();
System.out.println("---------"+b);
pstmt.close();
connection.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
DBDao.closeConnection(connection);
}
return b;
}
}
9>LoginServlet.java
package com.login.servlet;
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.dao.UserDao;
import com.user.User;
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("utf-8");
// 获取用户名和密码
String username = request.getParameter("username");
String password = request.getParameter("password");
// 获取UserDao实例
UserDao userDao = new UserDao();
User user = userDao.login(username, password);
// 判断user是否为空
if (user != null) {
// 转发到LoginSuccess.jsp页面
// getRequestDispatcher()是请求转发
request.getRequestDispatcher("LoginSuccess.jsp").forward(request,
response);
} else {
// 登录失败
request.getRequestDispatcher("LoginFailed.jsp").forward(request,
response);
}
System.out.println("-------******--------");
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
}
10>zhuCeServlet.java
package com.login.servlet;
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.dao.UserDao;
public class zhuCeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public zhuCeServlet() {
super();
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
System.out.println("zhuCeServlet.java访问我啦");
response.setCharacterEncoding("utf-8");
// 获取用户名和密码
String username = request.getParameter("username");
System.out.println("username----->" + username);
String password = request.getParameter("password1");
System.out.println("password----->" + password);
// 获取UserDao实例
UserDao userDao = new UserDao();
int i = userDao.zhuCe(username, password);
System.out.println("-----" + i);
// 判断i的值，为0表示未插入，为1表示插入一条数据
if (i != 0) {
System.out.println("-----------注册成功---------");
request.getRequestDispatcher("zhuCeSuccess.jsp").forward(request,
response);
} else {// 注册失败，仍然去注册页面 操作
System.out.println("000000000000000000000");
request.getRequestDispatcher("zhuCe.jsp")
.forward(request, response);
}
}
}
11>web.xml
mysql数据库，数据库名logindemo,表名userpwd.
