【六禕- Java】設置Cookie的訪問路徑，實現自動登錄的功能

爲什麼要設置訪問路徑？ 

如果沒有設置訪問路徑，默認是：當前web項目訪問地址，即：request.getContextPath()

只有訪問指定的路徑，瀏覽器纔將Cookie的數據發送給服務器。
如：實現自動登錄的功能，只能訪問登錄頁面的時候，纔將Cookie中用戶名和密碼發送給服務器。

/*
設置Cookie的訪問路徑
 */
@WebServlet("/demo6")
public class Demo6PathServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        //request.getContextPath()：得到當前web訪問地址
        out.print("Cookie的訪問路徑是：" + request.getContextPath() + "/login.html");
        //1.創建Cookie
        Cookie cookie = new Cookie("username", "Jack");
        //2.設置Cookie的訪問路徑
        cookie.setPath(request.getContextPath() + "/login.html");
        //3.將Cookie寫到瀏覽器端
        response.addCookie(cookie);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}