6_MVC模型总结_登陆

最新推荐文章于 2025-03-29 22:53:13 发布

原创最新推荐文章于 2025-03-29 22:53:13 发布 · 126 阅读

0 ·

CC 4.0 BY-SA版权

MVC 专栏收录该内容

7 篇文章

订阅专栏

Demo_01

package study;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

//模型层,用于处理登陆
public class Demo {
	//从数据库获取数据,验证是否够为数据库拥有的账户
	public static int login(UserMessage um){//返回值告诉view部分登陆是否成功
		PreparedStatement ps = null;
		Connection c = null;
		int count = 0;
		int flage = -1;//-1系统异常,0账号密码错误,1正常登陆
			try {
				Class.forName("com.mysql.jdbc.Driver");
				c = DriverManager.getConnection("jdbc:mysql://localhost:3306/login","root","root");								
				String sql = "select count(*) from login where name=? and password=?";
				ps = c.prepareStatement(sql);
				ps.setString(1, um.getName());
				ps.setString(2, um.getPassword());
				ResultSet rs = ps.executeQuery();
				if(rs.next()) {
					count = rs.getInt(1);
				}
				if(count>0) {
					flage = 1;
				}else {
					flage = 0;
				}
			} catch (ClassNotFoundException e) {
				e.printStackTrace();
				flage = -1;
			} catch (SQLException e) {
				e.printStackTrace();
				flage = -1;
			}finally {
//关闭
				try {
					if(ps != null) {
						ps.close();
						}
				} catch (SQLException e) {
					e.printStackTrace();
				}
				try {
					if(c != null) {
						c.close();						
					}
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
			return flage;
	}
}

Loginservlet.java

package study;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

//控制器层:接受view请求,并分发给model层处理
public class Loginservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//接收view中用户输入的数据
		request.setCharacterEncoding("utf-8");
		String name = request.getParameter("username");
		String password = request.getParameter("userpassword");
		UserMessage um = new UserMessage(name, password);
//调用模型层的登录功能
		int result = Demo.login(um);
		if(result == 1) {//登陆成功到welcome页面
			
			response.sendRedirect("welcome.jsp");
		}else {//失败,返回登陆页面
			response.sendRedirect("login.jsp");
		}
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

UserMessage.java

package study;
//获取用户在登陆页面输入的数据
public class UserMessage {
	private String name;
	private String password;
	public UserMessage() {
		
	}
	public UserMessage(String name,String password) {
		this.setName(name);
		this.setPassword(password);
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
}

<%@ 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>登陆</title>
</head>
<body>
		<form action="Loginservlet" method="post"><!-- 有密码一般用post -->
			用户名<input type="text" name="username"><br>
			密码<input type="password" name="userpassword"><br>
			<input type="submit" value="登陆">
		</form>
</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>Insert title here</title>
</head>
<body>
	welcome
</body>
</html>