Implementation code of forced login function in Java web project
- 2021-12-12 04:38:05
- OfStack
To avoid going directly to pages that exist in the project, use the filter filter
Create a new class loginFilter:
package com.tjcu.filter;
import com.tjcu.entity.User;
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{
@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;
HttpSession session = request.getSession();
User user = (User) session.getAttribute("user");
HttpServletResponse response = (HttpServletResponse) servletResponse;
if (user!=null) {
filterChain.doFilter(request,response);
}else {
response.sendRedirect(request.getContextPath()+"/login.jsp");
}
}
@Override
public void destroy() {
}
}
Notify the server that this filter has been developed in the web file
web.xml:
<filter>
<filter-name>loginFilter</filter-name>
<filter-class>com.tjcu.filter.loginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>loginFilter</filter-name>
<url-pattern>/main/*</url-pattern>
</filter-mapping>