软件工程概论-个人作业01-简单登录界面

Java+JavaBean+JDBC做基于数据库的登录验证

1.建立数据库yfyf 以及数据表login，表中包含两个字段，用户名字username和用户密码password；

2.建立JavaBean用于连接数据库及调用sql语句；代码如下：

package Bean;
import java.sql.*;
public class DBBean {
    private String driverStr = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
    private String connStr = "jdbc:sqlserver://localhost:1433; DatabaseName=yfyf";
    private String dbusername = "sa";
    private String dbpassword = "123456";
    private Connection conn = null;
    private Statement stmt = null;

    public DBBean()
    {
        try
        {
            Class.forName(driverStr);
            conn = DriverManager.getConnection(connStr, dbusername, dbpassword);
            stmt = conn.createStatement();
        } 
        catch (Exception ex) {
            System.out.println("数据连接失败！");
        } 
        
    }

    public int executeUpdate(String s) {
        int result = 0;
        System.out.println("--更新语句:"+s+"
");
        try {
            result = stmt.executeUpdate(s);
        } catch (Exception ex) {
            System.out.println("执行更新错误！");
        }
        return result;
    }

    public ResultSet executeQuery(String s) {
        ResultSet rs = null;
        System.out.print("--查询语句:"+s+"
");
        try {
            rs = stmt.executeQuery(s);
        } catch (Exception ex) {
            System.out.println("ִ执行查询错误！");
        }
        return rs;
    }


    public void close() {
        try {
            stmt.close();
            conn.close();
        } catch (Exception e) {
        }
    }
}

3.login.jsp实现登录界面展示；代码如下：

<%@ page import="java.sql.*" 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>登录界面</title>
</head>
<body>
    <center>
        <h1 style="color:red">登录</h1>
            <form id="indexform" name="indexForm" action="logincheck.jsp" method="post">
                <table border="0">
                    <tr>
                        <td>账号：</td>
                        <td><input type="text" name="username"></td>
                    </tr>
                    <tr>
                        <td>密码：</td>
                        <td><input type="password" name="password">
                        </td>
                    </tr>
                </table>
            <br>
                <input type="submit" value="登录" style="color:#BC8F8F">
            </form>

    </center>
</body>
</html>

4.logincheck.jsp实现登录验证；代码如下：

<%@ page import="java.sql.*" 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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<jsp:useBean id="db" class="Bean.DBBean" scope="page" />
<%
    request.setCharacterEncoding("UTF-8");
    String username=(String)request.getParameter("username");
    String password=(String)request.getParameter("password");//取出login.jsp的值
    
    //下面是数据库操作
    String sql="select * from login where username='"+username+"'";//定义一个查询语句
    ResultSet rs=db.executeQuery(sql);//运行上面的语句
    if(rs.next())
    {
        /* if(password.equals(rs.getString(2)))
        {
            
        } */
        if(password.equals(rs.getObject("password"))){
            response.sendRedirect("loginsuccess.jsp");
        }
        else{
            out.print("<script language='javaScript'> alert('密码错误');</script>");
            response.setHeader("refresh", "0;url=login.jsp");
        }
    }
    else 
    {
        out.print("<script language='javaScript'> alert('账号错误——else');</script>");
        response.setHeader("refresh", "0;url=login.jsp");
    }
    
%>
</body>
</html>

5.loginsuccess.jsp展示登陆成功界面；代码：

<%@ page import="java.sql.*" 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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>登录成功 </h1>
</body>
</html>

6.最终效果截图：

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原文地址：https://www.cnblogs.com/yifengyifeng/p/6520130.html