登入功能實現
阿新 • • 發佈：2022-06-01
登入功能實現
編寫前端登入頁面
1.編寫頁面程式碼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>系統登入 - 超市訂單管理系統</title> <link type="text/css" rel="stylesheet" href="${pageContext.request.contextPath }/css/style.css" /> <script type="text/javascript"> /* if(top.location!=self.location){ top.location=self.location; } */ </script> </head> <body class="login_bg"> <section class="loginBox"> <header class="loginHeader"> <h1>超市訂單管理系統</h1> </header> <section class="loginCont"> <form class="loginForm" action="${pageContext.request.contextPath }/login.do" name="actionForm" id="actionForm" method="post" > <div class="info">${error }</div> <div class="inputbox"> <label for="userCode">使用者名稱：</label> <input type="text" class="input-text" id="userCode" name="userCode" placeholder="請輸入使用者名稱" required/> </div> <div class="inputbox"> <label for="userPassword">密碼：</label> <input type="password" id="userPassword" name="userPassword" placeholder="請輸入密碼" required/> </div> <div class="subBtn"> <input type="submit" value="登入"/> <input type="reset" value="重置"/> </div> </form> </section> </section> </body> </html>
2.把這個登入頁面設定為首頁
如果不設定的話，預設首頁為index.jsp
<!--設定歡迎頁-->
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
Dao 層
1.編寫Dao層得到使用者登入的介面
import com.xy.pojo.User; import java.sql.Connection; public interface UserDao { //從資料庫查詢指定的使用者,這裡不需要獲取連線資料庫物件，交給業務層去做 public User getLoginUser(Connection connection, String userCode); }
2.編寫Dao層的實現類
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(); //將這些值丟給使用者 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; } }
業務層
1.編寫業務層介面
import com.xy.pojo.User;
import java.sql.SQLException;
public interface UserService {
//使用者登入
public User login(String userCode, String password) throws SQLException;
}
2.編寫業務層實現類
public class UserServiceImpl implements UserService{
//業務層都會呼叫Dao層，所以我們要引入Dao層
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();
//通過業務層調取對應的具體的資料庫的資料
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.編寫servlet：用於獲取前端請求的引數，並呼叫業務層判斷是否存在該使用者
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控制層：呼叫業務層
private UserService userService = new UserServiceImpl();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("LoginServlet-start...");
//獲取前端資料
String userCode = req.getParameter("userCode");
String userPassword = req.getParameter("userPassword");
User user = null;
//呼叫業務層相應的操作:和資料庫的使用者做對比
try {
user = userService.login(userCode,userPassword);
} catch (SQLException e) {
throw new RuntimeException(e);
}
if (user != null){
//將使用者的資訊放到session中
req.getSession().setAttribute(Constants.USER_SESSION,user);
//跳轉到主頁
resp.sendRedirect("jsp/frame.jsp");
}else {
//使用請求轉發到登入頁面，並提示使用者名稱或密碼錯誤
req.setAttribute("error","使用者名稱或密碼不正確");
req.getRequestDispatcher("/login.jsp").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
2.註冊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>