功能：实现简单的用户登录
0. 简单的流程
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>
<form action="registerDeal.jsp" method="post"> 用户名：<input type="text" name="username"/><br> 密码：<input type="password" name="password"/><br> 确认密码：<input type="password" name="password2"/><br> <input type="submit" value="提交" /> </form>
</html>
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2. RegisterDeal.jsp
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ page import="java.sql.Connection" %> <%@ page import="java.sql.DriverManager" %> <%@ page import="java.sql.PreparedStatement" %> <%@ page import="java.sql.SQLException" %> <%@ page import="java.sql.ResultSet" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>
<% String username = request.getParameter("username").trim(); String password = request.getParameter("password").trim(); String password2 = request.getParameter("password2").trim();
// 简单验证，不填其他的复杂逻辑 // save in database Connection conn = null; PreparedStatement pstat = null; String url = "jdbc:mysql://localhost:3306/ssh"; String user = "root"; String pw = "mysql123"; try { Class.forName("com.mysql.jdbc.Driver"); try { conn = DriverManager.getConnection(url, user, pw); String selectSql = "select count(*) from tb_user where username=?"; pstat = conn.prepareStatement(selectSql); pstat.setString(1, username); ResultSet rs = pstat.executeQuery(); rs.next(); int count = rs.getInt(1); if(count > 0) { //response.sendRedirect("registerFail.jsp"); request.getRequestDispatcher("registerFail.jsp").forward(request, response); return; }
String sql = "insert into tb_user(id, username, password) values(null, ?, ?)"; pstat = conn.prepareStatement(sql); pstat.setString(1, username); pstat.setString(2, password); pstat.executeUpdate();
//response.sendRedirect("registerSucess.jsp"); request.setAttribute("username", username); request.getRequestDispatcher("registerSucess.jsp").forward(request, response); } catch (SQLException e) { e.printStackTrace(); } } catch (ClassNotFoundException e) { e.printStackTrace(); } finally { if (null != pstat) pstat.close();
if (null != conn) conn.close(); }
%>
</html>
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在这个jsp里，实现了从请求里读取数据，连接数据库，判断数据库中是否已经存在要注册的用户名，如果不存在则允许当前用户注册，否则不允许注册。如果 注册成功就跳到显示注册成功信息的页面registerSucess.jsp，否则跳到注册失败的页面registerFail.jsp。为了简单没有添加其他复杂的逻辑和功能。整个过程流程是很简单的。
3. registerSucess.jsp
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>
registerSucess... <br/> welcome <font color="red" size="10px"><%=request.getAttribute("username") %></font>
</html>
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4. registerFail.jsp
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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>
registerFail...
</html>
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5. 数据库sql
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Create database ssh01; Use ssh01; Drop table tb_user; Create tabel tb_user( Id int auto_increment, Username varchar(30), Password varchar(30), Primary key(id) ); |
在工程的WEB-INFO下的lib目录下添加mysql的驱动jar包。部署项目并运行，测试项目是否成功。当数据库不存在相同的用户名时注册成功，否则注册失败！！
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6. 简单分析：
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此工程没有任何的模式或者是框架，所有的业务逻辑、操作数据库操作等都在jsp里实现，基本上没什么难点。但是维护修改比较麻烦！基本上不能重用。
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