标签：功能 userCode 登录 rs 实现 user import null User
登录功能实现
编写前端登录页面
1.编写页面代码login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>系统登录 - 超市订单管理系统</title>
<link type="text/css" rel="stylesheet" href="${pageContext.request.contextPath }/css/style.css" />
<script type="text/javascript">
/* if(top.location!=self.location){
top.location=self.location;
} */
</script>
</head>
<body class="login_bg">
<section class="loginBox">
<header class="loginHeader">
<h1>超市订单管理系统</h1>
</header>
<section class="loginCont">
<form class="loginForm" action="${pageContext.request.contextPath }/login.do" name="actionForm" id="actionForm" method="post" >
<div class="info">${error }</div>
<div class="inputbox">
<label for="userCode">用户名：</label>
<input type="text" class="input-text" id="userCode" name="userCode" placeholder="请输入用户名" required/>
</div>
<div class="inputbox">
<label for="userPassword">密码：</label>
<input type="password" id="userPassword" name="userPassword" placeholder="请输入密码" required/>
</div>
<div class="subBtn">
<input type="submit" value="登录"/>
<input type="reset" value="重置"/>
</div>
</form>
</section>
</section>
</body>
</html>
2.把这个登录页面设置为首页
如果不设置的话，默认首页为index.jsp
<!--设置欢迎页-->
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
Dao 层
1.编写Dao层得到用户登录的接口
import com.xy.pojo.User;
import java.sql.Connection;
public interface UserDao {
//从数据库查询指定的用户,这里不需要获取连接数据库对象，交给业务层去做
public User getLoginUser(Connection connection, String userCode);
}
2.编写Dao层的实现类
public class UserDaoImpl implements UserDao {
public User getLoginUser(Connection connection, String userCode) throws SQLException {
PreparedStatement statement = null;
ResultSet rs = null;
User user = null;
if (connection != null){
String sql = "select * from `smbms_user` where userCode=?";
Object[] param = {userCode};
rs = BaseDao.execute(connection, sql, param, statement, rs);
while (rs.next()){
user = new User();
//将这些值丢给用户
user.setId(rs.getInt("id"));
user.setUserCode(rs.getString("userCode"));
user.setUserName(rs.getString("userName"));
user.setUserPassword(rs.getString("userPassword"));
user.setGender(rs.getInt("gender"));
user.setBirthday(rs.getDate("birthday"));
user.setPhone(rs.getString("phone"));
user.setAddress(rs.getString("address"));
user.setUserRole(rs.getInt("userRole"));
user.setCreatedBy(rs.getInt("createdBy"));
user.setModifyBy(rs.getInt("modifyBy"));
user.setModifyDate(rs.getDate("modifyDate"));
}
BaseDao.close(null,statement,rs);
}
return user;
}
}
业务层
1.编写业务层接口
import com.xy.pojo.User;
import java.sql.SQLException;
public interface UserService {
//用户登录
public User login(String userCode, String password) throws SQLException;
}
2.编写业务层实现类
public class UserServiceImpl implements UserService{
//业务层都会调用Dao层，所以我们要引入Dao层
private UserDao userDao = null;
public UserServiceImpl(){
userDao = new UserDaoImpl();
}
public User login(String userCode, String password){
Connection connection = null;
User user = null;
try {
connection = BaseDao.getConnection();
//通过业务层调取对应的具体的数据库的数据
user = userDao.getLoginUser(connection,userCode);
} catch (SQLException e) {
e.printStackTrace();
}finally {
BaseDao.close(connection,null,null);
}
return user;
}
@Test
public void test(){
UserServiceImpl userService = new UserServiceImpl();
User admin = userService.login("admin", "1234567");
System.out.println(admin.getUserPassword());
}
}
Servlet
1.编写servlet：用于获取前端请求的参数，并调用业务层判断是否存在该用户
import com.xy.pojo.User;
import com.xy.service.user.UserService;
import com.xy.service.user.UserServiceImpl;
import com.xy.util.Constants;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.SQLException;
public class LoginServlet extends HttpServlet {
//servlet控制层：调用业务层
private UserService userService = new UserServiceImpl();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("LoginServlet-start...");
//获取前端数据
String userCode = req.getParameter("userCode");
String userPassword = req.getParameter("userPassword");
User user = null;
//调用业务层相应的操作:和数据库的用户做对比
try {
user = userService.login(userCode,userPassword);
} catch (SQLException e) {
throw new RuntimeException(e);
}
if (user != null){
//将用户的信息放到session中
req.getSession().setAttribute(Constants.USER_SESSION,user);
//跳转到主页
resp.sendRedirect("jsp/frame.jsp");
}else {
//使用请求转发到登录页面，并提示用户名或密码错误
req.setAttribute("error","用户名或密码不正确");
req.getRequestDispatcher("/login.jsp").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
2.注册servlet
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.xy.servlet.user.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>
标签：功能,userCode,登录,rs,实现,user,import,null,User 来源： https://www.cnblogs.com/xypersonal/p/16335331.html
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