SSM project uses filter to realize login monitoring

SSM Configure filters in the project to realize login monitoring , Some pages cannot be accessed without login

1. Write a class implementation of the filter Filter Interface , Add specific operations to the implementation method

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

public class LoginFilter implements Filter {
    
	// initialization ：web The server will initialize when it starts 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    
        HttpServletRequest request = (HttpServletRequest)servletRequest;
        HttpServletResponse response =(HttpServletResponse)servletResponse;
        HttpSession session = request.getSession();
        if (session.getAttribute("loginuser")==null){
    
            response.sendRedirect(request.getContextPath()+"/login/adminLogin.jsp");
        }else {
    
        	// Let the request go on , If you don't write , Requests will be blocked here 
            filterChain.doFilter(servletRequest,servletResponse);
        }
    }
	
	// The destruction ,web It will be destroyed when the server is shut down 
    @Override
    public void destroy() {
    

    }

2. stay web.xml Filter in

<filter>
        <filter-name>LoginFilter</filter-name>
        <!--  Realization filter The class of the interface  -->
        <filter-class>edu.gnnu.newcomer.aop.LoginFilter</filter-class>
</filter>
<filter-mapping>
        <filter-name>LoginFilter</filter-name>
        <!--  Pages to filter  -->
        <url-pattern>/manager/*</url-pattern>
</filter-mapping>

After configuration, these pages will be filtered first , If the conditions in the filter are not met, perform the operations defined in the filter