//JavaWeb

package com.wyw.text.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.wyw.text.Dao.UserDao;
import com.wyw.text.Dao.impl.UserDaoimpl;
import com.wyw.text.domin.User;

@WebServlet("/loginservlet")
public class loginservlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    public loginservlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/heml;charset=utf-8");
		request.setCharacterEncoding("utf-8");
		String username=request.getParameter("username");
		String password=request.getParameter("password");
		UserDao userDao=new UserDaoimpl();
		User user=userDao.addfind(username, password);
		if(user==null){
			request.setAttribute("pwd", "用户名或者密码错误");
			request.getRequestDispatcher("/login.jsp").forward(request,response);
			return ;
		}else{
			request.getSession().setAttribute("user", user);
			response.sendRedirect(request.getContextPath()+"/index.jsp");
			return ;
		}
	}

}

package com.kob.backend.config.filter;

import com.kob.backend.mapper.UserMapper;
import com.kob.backend.pojo.User;
import com.kob.backend.service.impl.utils.UserDetailsImpl;
import com.kob.backend.utils.JwtUtil;
import io.jsonwebtoken.Claims;
import org.jetbrains.annotations.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class JwtAuthenticationTokenFilter extends OncePerRequestFilter {
    @Autowired
    private UserMapper userMapper;

    @Override
    protected void doFilterInternal(HttpServletRequest request, @NotNull HttpServletResponse response, @NotNull FilterChain filterChain) throws ServletException, IOException {
        String token = request.getHeader("Authorization");

        if (!StringUtils.hasText(token) || !token.startsWith("Bearer ")) {
            filterChain.doFilter(request, response);
            return;
        }

        token = token.substring(7);

        String userid;
        try {
            Claims claims = JwtUtil.parseJWT(token);
            userid = claims.getSubject();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

        User user = userMapper.selectById(Integer.parseInt(userid));

        if (user == null) {
            throw new RuntimeException("用户名未登录");
        }

        UserDetailsImpl loginUser = new UserDetailsImpl(user);
        UsernamePasswordAuthenticationToken authenticationToken =
                new UsernamePasswordAuthenticationToken(loginUser, null, null);

        SecurityContextHolder.getContext().setAuthentication(authenticationToken);

        filterChain.doFilter(request, response);
    }
}