javabean+servlet应用
login.jsp
<%@ page language="java" isErrorPage="true" pageEncoding="utf-8"%>
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title></title>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<div class="container">
<section id="content">
<form action="${pageContext.request.contextPath}/Servlet/Userservlet?method=login" method="post"><!---${pageContext.request.contextPath}的目的是找到主工程的名字，/Servlet/Userservlet就是web.xml下面配置的路径，也就是servlet的路径--->
<h1>登录 界面</h1>
<div>
<input type="text" placeholder="登录名" required="" id="username" name="username1"/>
</div>
<div>
<input type="password" placeholder="密码" required="" id="password" name="password1" />
</div>
<div>
<input type="submit" value="登 录" />
<a href="#">注册</a>
</div>
</form><!-- form -->
<div class="button">
</div><!-- button -->
</section><!-- content -->
</div><!-- container -->
</body>
</html>
userbean.java
package bean;
public class Userbean {
private String username;//用户名
private String password;//密码都是与数据库匹配的，下面是set和get函数
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;
}
}
userservlet.java
package servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import dao.Userdao;
@SuppressWarnings("serial")
public class Userservlet extends HttpServlet
{
//当从jsp跳转到servlet类时，首先执行service函数（这是定理）
protected void service(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException
{
req.setCharacterEncoding("utf-8");//设置字符集，避免乱码
//获取jsp界面需要进行的操作，
String method = req.getParameter("method");
if(method.equals("login"))//转到login函数
{
login(req,resp);
}
}
protected void login(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException
{
req.setCharacterEncoding("utf-8");
String username = req.getParameter("username1");//获取jsp界面的username1和password1的值
String password = req.getParameter("password1");
Userdao userdao = new Userdao();//创建Userdao的实例
int flag = userdao.login(username, password);//用来判断是否登陆成功
if(flag==1)
{
System.out.println("登录成功！");
resp.sendRedirect(req.getContextPath()+"/index.jsp");
}
else
{
System.out.println("登录失败！");
}
}
}
userdao.java
package dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import db.DBUtil;
public class Userdao {
public int login(String username,String password)
{
Connection conn = DBUtil.getConn();//这里就是从DBUtil类里面得到连接
Statement state =null;
ResultSet rs = null;
int flag=0;
try
{
String sql = "select * from user where name = '"+username+"'";//SQL语句,
state = conn.createStatement();
rs=state.executeQuery(sql);
if(rs.next())
{
if(rs.getString("password").equals(password))
{
flag=1;
}
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
DBUtil.close(rs, state, conn);
}
return flag;
}
}
