登入登出，自動登入
阿新 • • 發佈：2018-11-01
UserLoggingDao：
public interface UserLoggingDao {
// 根據賬號獲取使用者資訊
User findByAccount(String account);
}
UserLoggingDaoImpl：
public class UserLoggingDaoImpl implements UserLoggingDao{ @Override public User findByAccount(String account) { //定義一個User User user = null; try { //連線資料庫 Connection conn = DBUtils.getConnection(); //輸入sql語句 String sql = "SELECT id, password FROM user WHERE account=?;"; PreparedStatement ps = conn.prepareStatement(sql); //新增？中的資料 ps.setString(1, account); //執行 ResultSet rs = ps.executeQuery(); while(rs.next()) { //獲取資料庫中搜索的值 Integer id = rs.getInt(1); String Password = rs.getString(2); //新增資料到user user = new User(); user.setId(id); user.setAccount(account); user.setPassword(Password); } //關閉流 rs.close(); ps.close(); conn.close(); } catch (ClassNotFoundException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } //返回user return user; } }
UserLoggingService：
public interface UserLoggingService {
//根據account和password獲取登入結果
boolean login(String account,String password);
}
UserLoggingServiceImpl：
public class UserLoggingServiceImpl implements UserLoggingService { private UserLoggingDao userLoggingDao = new UserLoggingDaoImpl(); @Override public boolean login(String account, String password) { User user = userLoggingDao.findByAccount(account); if(user == null){ //賬號不存在 return false; } if (!user.getPassword().equals(password)) { // 密碼不相同 return false; } //密碼一致 return true; } }
LoginServlet：
/** * Servlet implementation class LoginServlet */ public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; private UserLoggingService userLoggingService = new UserLoggingServiceImpl(); /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //接收網頁的資料 String account = request.getParameter("account"); String password = request.getParameter("password"); //如果相應資料有中文 還需要設定相應頭才能正確顯示 response.setHeader("content-Type", "text/html;charset=utf-8"); if(userLoggingService.login(account, password)){ // 把賬號存入 session HttpSession session = request.getSession(); session.setAttribute("account", account); // 自動登入第 1 步：登入成功後把賬號和密碼傳送給瀏覽器，儲存在 cookie 中 Cookie accountCookie = new Cookie("account", account); Cookie passwordCookie = new Cookie("password", password); accountCookie.setMaxAge(3600); passwordCookie.setMaxAge(3600); // 把 cookie 新增到 response 中，傳送給 client。 // 如果 client 是瀏覽器，會自動儲存接收到的 cookie response.addCookie(accountCookie); response.addCookie(passwordCookie); //登陸成功 重定向到 admin response.sendRedirect("admin.jsp"); }else{ //登入失敗，轉發請求到login request.setAttribute("errorMessage", "檢查一下賬號和密碼，再輸入一下哦~"); request.getRequestDispatcher("/login.jsp").forward(request, response); } } }
LogoutServlet：
/**
* Servlet implementation class LogoutServlet
*/
public class LogoutServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 清除 session 中儲存的資料
HttpSession session = request.getSession();
//直接銷燬
session.invalidate();
// 重定向到 login.jsp
response.sendRedirect(request.getContextPath() + "/login.jsp");
}
}
IndexServlet：
/**
* Servlet implementation class IndexServlet
*/
public class IndexServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private UserLoggingService userLoggingService = new UserLoggingServiceImpl();
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 自動登入第 2 步：獲取 request 的 cookie 中是 account 和 password 的值
String cookieAccount = null; // cookie 中的密碼
String cookiePassword = null; // cookie 中的賬號
// 獲取請求中的所有 cookie 資訊
Cookie[] cookies = request.getCookies();
// 如果 cookies 不為 null，遍歷陣列，找出 account 和 password
if (cookies != null) {
for (Cookie cookie : cookies) {
// 根據 key 尋找 account 和 password 的 value
String key = cookie.getName();
if ("account".equals(key)) {
cookieAccount = cookie.getValue();
}else if ("password".equals(key)) {
cookiePassword = cookie.getValue();
}
}
}
// 如果 cookie 有賬號和密碼，進行登入驗證
if (cookieAccount != null && cookiePassword != null) {
if (userLoggingService.login(cookieAccount, cookiePassword)) {
// 把賬號存入 session，那麼其它 jsp 和 servlet 都可以使用了
HttpSession session = request.getSession(); // 獲取當前 client 對應的 session
session.setAttribute("account", cookieAccount); // 資料以 key=value 的形式存入 session 中
// 登入成功，重定向到 list.jsp
response.sendRedirect(request.getContextPath() + "/admin.jsp");
}else {
// 追加錯誤資訊，轉發給 login.jsp 重新輸入賬號密碼
request.setAttribute("errorMessage", "請重新登入喲！");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}else {
// 如果沒有，重定向到 login.jsp 進行手動登入
response.sendRedirect(request.getContextPath() + "/login.jsp");
}
}
}