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javaSE web开发登录思路代码

准备工作：

1.在WebContent WEB-INF lib下添加c3p0-0.9.5.2.jar mchange-common-java-0.2.11.jar ojdbc6.jar

2.java Resources中的src平级的添加c3p0-config.xml

Java Resources

src

三个包

com.hanqi.dao 　　　　　　数据库有关

BankCard.java实体类　　属性 getter setter toString 有参构造无参构造

BankCardDAO.java　　　功能类数据库增删改查

DBHelper.java　　　　　　单例的数据库工具类返回数据连接连接池

com.hanqi.service

BankCardService.java　　业务逻辑类

com.hanqi.web　　　　　　

CheckLoginServlet.java　　

MyFilter.java　　　　　　　　过滤器

WebContent

Main.jsp 主页面

<%@ 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>


<form action="CheckLoginServlet" method="POST">

卡号：<input type="text" name="cardid" value=""><br>
密码：<input type="password" name="password"><br>

<input type="submit" value="登录">

</form>

</body>
</html>

CheckLoginServlet.java

package com.hanqi.web;

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

import com.hanqi.dao.BankCard;
import com.hanqi.service.BankCardService;

/**
 * Servlet implementation class CheckLoginServlet
 */
public class CheckLoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CheckLoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // 接收参数
        String cardid = request.getParameter("cardid");
        String password = request.getParameter("password");    
        
        // 对get,post同时有效
        //cardid = new String(cardid.getBytes("ISO-8859-1"), "UTF-8");
            
        // 检查参数
        if (cardid == null || password == null
                || cardid.trim().equals("") 
                || password.trim().equals(""))
        {
            response.getWriter().println("请正确登录");
            
            response.setHeader("refresh", "3;url=Login.jsp");
        }
        else
        {            
            // 验证参数
            // 调用Service层
            BankCard bc = new BankCardService().checkLogin(cardid, password);
            
            if (bc != null)
            {                
                // 创建session
                HttpSession hs = request.getSession();
                
                hs.setAttribute("bankcard", bc);
                
                // 跳转
                response.sendRedirect("Main.jsp");
            }
            else
            {
                response.getWriter().println("卡号或密码错误" + " cardid = " + cardid);
                
                response.setHeader("refresh", "3;url=Login.jsp");
            }            
        }
        
        
    }

    /**
     * @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);
    }

}

BankCard.java

package com.hanqi.dao;

import java.util.Date;

// 实体类
public class BankCard {
    
    private String cardID;
    private String userID;
    private String userName;
    private String password;
    private double balance;
    private String state;
    private Date createTime;
    public String getCardID() {
        return cardID;
    }
    public void setCardID(String cardID) {
        this.cardID = cardID;
    }
    public String getUserID() {
        return userID;
    }
    public void setUserID(String userID) {
        this.userID = userID;
    }
    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 double getBalance() {
        return balance;
    }
    public void setBalance(double balance) {
        this.balance = balance;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public Date getCreateTime() {
        return createTime;
    }
    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
    public BankCard(String userID, String userName, String password) {
        super();
        this.userID = userID;
        this.userName = userName;
        this.password = password;
    }
    public BankCard() {
        super();
    }
    @Override
    public String toString() {
        return "BankCard [cardID=" + cardID + ", userID=" + userID + ", userName=" + userName + ", password=" + password
                + ", balance=" + balance + ", state=" + state + ", createTime=" + createTime + "]";
    }

    
}

BankCardDAO.java

package com.hanqi.dao;

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

// 数据库操作类
public class BankCardDAO {
    
    // 查
    // 单条查询
    public BankCard getBankCard(String cardid)
    {
        BankCard rtn = null;
        
        // 查询
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        
        try {
            conn = DBHelper.getDBHelper().getConnection();
            
            String sql = "select * from t_bankcard where card_id = ?";
            
            ps = conn.prepareStatement(sql);
            
            ps.setString(1, cardid);
            
            rs = ps.executeQuery();
            
            if (rs.next())
            {
                rtn = new BankCard();
                
                rtn.setCardID(cardid);
                rtn.setBalance(rs.getDouble("Balance"));
                rtn.setCreateTime(rs.getDate("create_time"));
                rtn.setPassword(rs.getString("password"));
                rtn.setState(rs.getString("state"));
                rtn.setUserID(rs.getString("user_id"));
                rtn.setUserName(rs.getString("user_name"));
            }            
            
        } catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            
            try {
                rs.close();
            } catch (SQLException e2) {
            }
            
            try {
                ps.close();
            } catch (SQLException e1) {
            }
            
            try {
                conn.close();
            } catch (SQLException e) {
            }
            
        }        
        
        return rtn;
    }
    
    // 增
    
    // 改
    
    // 删

}

DBHelper.java

package com.hanqi.dao;

import java.sql.Connection;
import java.sql.SQLException;

import com.mchange.v2.c3p0.ComboPooledDataSource;

// 单例模式的数据库工具类
// 返回数据库连接
public class DBHelper {
    
    // 1 隐藏默认构造方法
    private DBHelper()
    {
        
    }
    
    // 2 静态实例
    private static DBHelper dh;
    
    // 3 返回实例的静态方法
    public static DBHelper getDBHelper()
    {
        if (dh == null)
        {
            dh = new DBHelper();
        }
        
        return dh;
    }
    
    private ComboPooledDataSource cpds = new ComboPooledDataSource("helloc3p0");
    
    // 返回连接的方法
    public Connection getConnection() throws SQLException
    {
        return cpds.getConnection();
    }
    
}

MyFilter.java

package com.hanqi.web;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * Servlet Filter implementation class MyFilter
 */
public class MyFilter implements Filter {

    /**
     * Default constructor. 
     */
    public MyFilter() {
        // TODO Auto-generated constructor stub
    }

    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }

    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

        // 设置编码
        request.setCharacterEncoding("UTF-8");
        
        response.setContentType("text/html");
        response.setCharacterEncoding("UTF-8");
        
        chain.doFilter(request, response);
    }

    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}

BankCardService.java

package com.hanqi.service;

import com.hanqi.dao.BankCard;
import com.hanqi.dao.BankCardDAO;

// 业务逻辑类
public class BankCardService {
    
    // 验证登录方法
    public BankCard checkLogin(String cardid, String password)
    {
        BankCard rtn = null;
        
        // 得到卡信息
        BankCard bc = new BankCardDAO().getBankCard(cardid);
        
        if (bc != null)
        {
            // 验证数据有效性
            if (bc.getState().equals("1") 
                    && bc.getPassword().equals(password))
            {
                rtn = bc;
            }
        }        
        
        return rtn;
    }

}

Main.jsp

<%@page import="com.hanqi.dao.BankCard"%>
<%@ 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>

主页面  
<br>
<%

Object obj = session.getAttribute("bankcard");

if (obj == null)
{
    out.print("会话超时或未登录");
    
    response.setHeader("refresh", "3;url=Login.jsp");
}
else
{
    BankCard bc = (BankCard)obj;
    
    out.print("欢迎登录！" + bc.getUserName());
}

%>


</body>
</html>

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原文地址：https://www.cnblogs.com/hanruyue/p/6024267.html

javaSE web开发 登录思路代码

javaSE web开发登录思路代码