JAVA学习笔记028——纯JSP操作操作MySQL数据库实例

两个页面login2.jsp 和 check2.jsp

数据表里存放用户名和密码，在login2.jsp页面上输入用户名密码登录，如果成功，显示“登录成功”，如果失败，显示“登录失败”。

核心：将JAVA中的JDBC代码，复制到JSP中的<% ... %>

注意事项：需要将MySQL jar包导入到WEB-INF下的lib目录下

login2.jsp代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录界面</title>
</head>
<body>
	<form action="check2.jsp" method="post">
	 	用户名：<input type="text" name="uname" /> <br/>
	 	密码：<input type="password" name="upwd" /><br/>
	 	<input type="submit" value="登录"/><br/>
	
	</form>


</body>
</html>

check2.jsp代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.sql.*"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>检验界面</title>
</head>
<body>
	<%
	String URL="jdbc:mysql://localhost:3306/lds?serverTimezone=UTC";
	String USERNAME="root";
	String PWD="prolific";
	Connection connection = null;
	PreparedStatement pstmt =null;
	ResultSet rs=null;
	try {
		//  a.导入驱动，加载具体的驱动类
		Class.forName("com.mysql.cj.jdbc.Driver");//加载具体的驱动类
		//      b.与数据库建立连接
		connection = DriverManager.getConnection(URL,USERNAME,PWD);
		//c.发送sql，执行(增、删、改、查)
		String sql="select count(*)from login where uname=? and upwd=?";
		pstmt=connection.prepareStatement(sql);

		String name=request.getParameter("uname");
		String pwd=request.getParameter("upwd");
		
		pstmt.setString(1,name);
		pstmt.setString(2,pwd);


        //String sql="select count(*)from login where uname='"+name+"' and upwd='"+pwd+"'";
		rs=pstmt.executeQuery();
	
		int count =-1;
		if(rs.next()) {
			count=rs.getInt(1);
		}
		if (count>0) {
			out.println("登录成功!");
		}
		else {
			out.println("登录失败!");
		}
		
	}  catch (ClassNotFoundException e) {
		e.printStackTrace();
	} catch (SQLException e) {
		e.printStackTrace();
	}catch(Exception e){
  e.printStackTrace();
	}
	finally{
		try {
			if(rs!=null) rs.close();
			if (pstmt!=null) pstmt.close();   //对象.方法
			if (connection!=null) connection.close();			
		}catch(SQLException e) {
			e.printStackTrace();
		}
		
	}
	
	
	%>

</body>
</html>

JAVA学习笔记028——纯JSP操作操作MySQL数据库实例

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