JSP_5.16_课堂笔记

完整的可以与数据库连接的登录界面的代码

login.jsp

<%@ page language="java" contentType="text/html; UTF-8"
    pageEncoding="UTF-8"%>
    
<!DOCTYPE html>
    <html>
        <head>
            <meta charset="UTF-8">
            <title>登录页面</title>
            <script src="js/jquery-3.3.1.min.js"></script>
            <style type="text/css">
                #diceng{
                    width:430px;
                    height:380px;
                    background-color:#FFFFFF33;
                    position:absolute;
                    left:50%;
                    top:50%;
                    margin-left:-215px;
                    margin-top:-190px;
                    border-radius:5px;
                }
                #zhongceng{
                    width:400px;
                    height:350px;
                    background-color:#FFFFFFFF;
                    position:absolute;
                    left:50%;
                    top:50%;
                    margin-left:-200px;
                    margin-top:-175px;
                    border-radius:5px;
                }
                #d1{
                    width:400px;
                    height:60px;
                    font-size:30px;
                    font-family:Avenir,Helvetica,Arial,sans-serif;
                    color:black;
                    display:block;
                    margin-left:40px;
                    margin-top:20px;
                    
                }
                #d2{
                    width:400px;
                    height:35px;
                    font-size:20px;
                    font-family:Avenir,Helvetica,Arial,sans-serif;
                    color:black;
                    display:block;
                    margin-left:40px;
                    
                }
                #d3{
                    width:400px;
                    height:35px;
                    font-size:20px;
                    font-family:Avenir,Helvetica,Arial,sans-serif;
                    color:black;
                    display:block;
                    margin-left:40px;
                    
                }
                #username{
                    width:280px;
                    height:40px;
                    font-size:30px;
                    font-family:Avenir,Helvetica,Arial,sans-serif;
                    color:black;
                    display:block;
                    margin-left:40px;
                    border-radius:5px;
                    
                }
                #password{
                    width:280px;
                    height:40px;
                    font-size:30px;
                    font-family:Avenir,Helvetica,Arial,sans-serif;
                    color:black;
                    display:block;
                    margin-left:40px;
                    border-radius:5px;
                    
                    
                }
                #submit{
                    width:237px;
                    height:40px;
                    margin-top: 5px;
                    background-color: #47a0fc;
                    border: 1px solid #47a0fc;
                    color: #fff;
                    font-size: 14px;
                    cursor: pointer;
                    outline: none;
                    border-radius: 2px;
                    display:block;
                    margin-left:65px;
                    margin-top:15px;
                    border-radius:5px;
                    
                }
                .bjimg {
                    position: fixed;
                    top: 0;
                    left: 0;
                    width: 100%;
                    height: 100%;
                    min-width: 1000px;
                    z-index: -10;
                    zoom: 1;
                    background-color: #fff;
                    background-repeat: no-repeat;
                    background-size: cover;
                    -webkit-background-size: cover;
                    -o-background-size: cover;
                    background-position: center 0;
                    background-image:url("https://w.wallhaven.cc/full/ex/wallhaven-ex9ork.jpg")
                    }
            </style>
        </head>
    <body>
        <div class="bjimg"></div>
        <div id=diceng>
            <div id=zhongceng>
            
                    <div id=d1>欢迎登录优逸客实训平台</div>
                    <div id=d2>用户名</div>
                    <input id=username type='text' placeholder="请输入用户名"></input>
                    <div id=d3>密码</div>
                    <input id=password type="password" placeholder="请输入密码"></input>
                    <button id=submit>登录</button>
            </div>
        </div>
        <script>
    $(document).ready(function(){
        $("#submit").click(function(){
            var username = $("#username").val(); // 获取用户名
            var password = $("#password").val(); // 获取密码
            if(username == "" || password == ""){
                alert("请输入用户名和密码!"); // 输入为空,提示用户
                return;
            }
            $.ajax({
                url: "jdbclogin.jsp?username="+username+"&password="+password, // 后端处理jsp文件
                type: "GET",
                dataType:'json',
                success: function(res){
                    if(res.msg== "success"){
                        window.location.href = "main.jsp"; // 登录成功,跳转到主页
                    }else{
                        alert("用户名或密码错误!"); // 登录失败,提示用户
                    }
                }
            });
        });
    });
</script>
    </body>
</html>

jdbclogin.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page import="java.sql.*" %>
<%@page import="java.io.PrintWriter"%>
<%
    String username = request.getParameter("username"); // 获取用户名
    String password = request.getParameter("password"); // 获取密码
    PrintWriter writer = response.getWriter();
    response.setCharacterEncoding("UTF-8");
	Class.forName("com.mysql.cj.jdbc.Driver");
	Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/study?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "000000"); // 建立数据库连接
	Statement stat = conn.createStatement();
	String sql = "SELECT * FROM user WHERE username='"+username+"' AND password='"+password+"'";
	ResultSet rs = stat.executeQuery(sql); // 执行查询
	if(rs.next()){
		   writer.write("{\"msg\":\"success\"}");
		   writer.flush();
		 }else{
		   writer.write("{\"msg\":\"fail\"}");
		   writer.flush();
		 }
   	rs.close();
   	stat.close();
   	conn.close();

%>

register.jsp

<%@ page language="java" contentType="text/html; UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
	<html>
		<head>
			<meta charset="UTF-8">
			<title>注册页面</title>
			<script src="js/jquery-3.3.1.min.js"></script>
			<style type="text/css">
				#diceng{
					width:430px;
					height:380px;
					background-color:#FFFFFF33;
					position:absolute;
					left:50%;
					top:50%;
					margin-left:-215px;
					margin-top:-190px;
					border-radius:5px;
				}
				#zhongceng{
					width:400px;
					height:350px;
					background-color:#FFFFFFFF;
					position:absolute;
					left:50%;
					top:50%;
					margin-left:-200px;
					margin-top:-175px;
					border-radius:5px;
				}
				#d1{
					width:400px;
					height:40px;
					font-size:30px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					margin-top:20px;
					
				}
				#d2{
					width:400px;
					height:35px;
					font-size:20px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					
				}
				#d3{
					width:400px;
					height:35px;
					font-size:20px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					
				}
				#d7{
					width:400px;
					height:35px;
					font-size:20px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					
				}
				#username{
					width:280px;
					height:30px;
					font-size:30px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					border-radius:5px;
					
				}
				#password1{
					width:280px;
					height:30px;
					font-size:30px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					border-radius:5px;
					
					
				}
				#password2{
					width:280px;
					height:30px;
					font-size:30px;
					font-family:Avenir,Helvetica,Arial,sans-serif;
					color:black;
					display:block;
					margin-left:40px;
					border-radius:5px;
					
					
				}
				#submit{
					width:237px;
					height:40px;
				    margin-top: 5px;
				    background-color: #47a0fc;
				    border: 1px solid #47a0fc;
				    color: #fff;
				    font-size: 20px;
				    cursor: pointer;
				    outline: none;
				    border-radius: 2px;
					display:block;
					margin-left:65px;
					margin-top:15px;
					border-radius:5px;
					
				}
				.bjimg {
				    position: fixed;
				    top: 0;
				    left: 0;
				    width: 100%;
				    height: 100%;
				    min-width: 1000px;
				    z-index: -10;
				    zoom: 1;
				    background-color: #fff;
				    background-repeat: no-repeat;
				    background-size: cover;
				    -webkit-background-size: cover;
				    -o-background-size: cover;
				    background-position: center 0;
					background-image:url("https://w.wallhaven.cc/full/ex/wallhaven-ex9ork.jpg")
					}
			</style>
		</head>
	<body>
		<div class="bjimg"></div>
		<div id=diceng>
			<div id=zhongceng>
					<div id=d1>欢迎注册优逸客实训平台</div>
					<div id=d2>用户名</div>
					<input type='text' placeholder="请输入用户名" id="username"></input>
					<div id=d3>密码</div>
					<input type="password" placeholder="请输入密码" id="password1"></input>
					<div id=d7>再次输入密码</div>
					<input type="password" placeholder="请重新输入密码" id="password2"></input>
					<button id=submit onclick="register()">注册</button>
			</div>
		</div>
	<script type="text/javascript">
    		function register(){
    			var username = $("#username")[0].value;
    			var password1 = $("#password1")[0].value;
    			var password2 = $("#password2")[0].value;
            $.ajax({
                url: "jdbcregister.jsp?username="+username+"&password1="+password1+"&password2="+password2,
                type: "GET",
                dataType:"json",
                success: function(res){
                	
                    if(res.msg == "success"){
                        window.location.href = "login.jsp";
                    }else{
                        alert("注册失败!");
                    }
                }
            })
    }
</script>
	</body>
</html>

jdbcregister.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.Statement"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>
<%@page import="java.io.PrintWriter"%>
<%
    String username = request.getParameter("username");
    String password1 = request.getParameter("password1");
    String password2 = request.getParameter("password2");
    response.setCharacterEncoding("UTF-8"); //设置交换数据时的数据格式
    PrintWriter writer = response.getWriter();
    if(password1.equals(password2)){
	    Class.forName("com.mysql.jdbc.Driver");
	    
	    Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/study?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "000000");
	    String sql = "Select * from user where username='"+username+"'";
	    Statement stat = conn.createStatement();
	    ResultSet rs = stat.executeQuery(sql);
	        if(rs.next()){
	        	 writer.write("{\"msg\":\"fail\"}");
	             writer.flush();
	        	}else{
	    		String sql2 ="insert into user(username,password) values('"+username+"','"+password1+"')";
	    		int num = stat.executeUpdate(sql2);
	            if(num > 0){
	               		writer.write("{\"msg\":\"success\"}");
	               		writer.flush();
	             	}else{
	               		writer.write("{\"msg\":\"fail\"}");
	               		writer.flush();
	             	}
	            }
	    	}
	        else{
	        	   writer.write("{\"msg\":\"fail\"}");
	        	   writer.flush();
	            }
             
%>

main.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
	<head>
		<title>登陆成功</title>
		<style>
		body {
		background-image: url("https://w.wallhaven.cc/full/j3/wallhaven-j3m8y5.png");
		background-size: cover;
		background-position: center center;
		font-family: 'Microsoft YaHei', sans-serif;
		color: white;
		}
		#header {
		background-color: rgba(0, 0, 0, 0.5);
		padding: 20px;
		display: flex;
		align-items: center;
		justify-content: space-between;
		}
		#header img {
		height: 80px;
		border-radius: 50%;
		margin-right: 20px;
		}
		h1 {
		font-size: 48px;
		margin: 0;
		font-weight: bold;
		font-style: italic;
		text-shadow: 2px 2px 4px #000000;
		}
		nav {
		background-color: rgba(0, 0, 0, 0.5);
		padding: 10px;
		display: flex;
		justify-content: center;
		}
		nav a {
		color: white;
		text-decoration: none;
		margin: 0 10px;
		font-size: 24px;
		font-weight: bold;
		text-transform: uppercase;
		letter-spacing: 2px;
		transition: all 0.3s ease;
		}
		nav a:hover {
		color: #00ff00;
		}
		</style>
	</head>
	<body>
		<header id="header">
			<img src="http://mms2.baidu.com/it/u=983221791,942132541&fm=253&app=138&f=JPEG&fmt=auto&q=75?w=320&h=307" alt="Avatar">
			<h1>登陆成功!</h1>
		</header>
			<nav>
			<a href="#">首页</a>
			<a href="#">关于</a>
			<a href="#">联系我</a>
			<a href="#">QQ</a>
			<a href="#">微信</a>
			</nav>
		<main>
			<p style="font-size: 60px; font-weight: bold;"></p>
		</main>
	</body>
</html>

5.16笔记

一、JDBC回顾

JDBC技术Java用来连接操作数据库的工具,JDBC严格意义上属于Java的一种技术。JDBC连接操作数据库时,整体一共分为七步(需要引入编程依赖)。

1、加载驱动(告诉JDBC程序,连接的是哪一个数据库)

Class.forName(“驱动程序名”);
MySQL: com.mysql.jdbc.Driver com.mysql.cj.jdbc.Driver
Oracle: oracle.jdbc.driver.OracleDriver
SQL Server: com.microsoft.jdbc.sqlserver.SQLServerDriver

2、获取和数据库之间的连接—java.sql.DriverManager

Connection conn = DriverManager.getConnection(三个参数);
三个参数也成为数据库连接三要素:
URL:数据库的地址、连接的数据库的名字、连接数据库使用的参数
MySQL: jdbc:mysql://ip:port/databaseName?key=value&key=value
Oracle: jdbc:oracle:thin:@IP地址:端口号:数据库名
SQL Server: jdbc:microsoft:sqlserver://IP地址:端口号;DatabaseName=数据库名
用户名: 数据库的用户名
密码:数据库的密码

3、准备SQL语句

String sql = “xxxxx”;
JDBC操作数据库时,一般执行的SQL语句都是DMLDQL类型的语言。
SQL语句中存在一些字符串,字符串最好使用单引号

4、创建小推车—java.sql.Statement

Statement stat = conn.createStatement();
小推车是JDBC的核心,SQL语句的执行以及执行结果的返回都是Statement实现的

5、小推车带着SQL语句去数据库执行SQL语句,并且返回执行结果

JDBC操作SQL,SQL一般分为两类:DMLDQL,两类SQL语句的执行方式以及返回结果都是不同的。
执行DML类型的SQL:--返回的是一个数字,这个数字代表数据库受影响的行数
int num = stat.executeUpdate(DMLSQL);
执行DQL类型SQL—返回的是一个ResultSet结果集,结果集就是查询回来的虚拟表格,
ResultSet rs = stat.executeQuery(DQLSQL);

6、Java程序处理逻辑

如果执行的是DML类型的SQL语句,Java程序只需要判断是否执行成功即可
如果执行的是DQL类型的SQL语句,Java程序需要获取ResultSet结果集当中封装的虚拟表格数据。

7、释放JDBC程序使用的资源

ResultSet Statement Connection
如果执行的是DML类型的SQL,只需要释放两个Statement Connection
如果执行的是DQL类型的SQL,需要释放这三个

释放顺序:先创建的后释放后创建的先释放
释放调用这三者的close()方法即可。

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