tomcat出现请求的资源[/med_war_exploded/..]不可用问题

index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<form method="post" action="LoginServlet">
账号:<input type="text" name="id"><br>
密码:<input type="password" name="pwd"><br>
<input type="submit" value="登录">
</form>
</body>
</html>
LoginServlet.java
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}