一、编写UserDetailService类实现UserDetailsService接口

package com.zh.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.zh.domain.entity.LoginUser;
import com.zh.domain.entity.User;
import com.zh.mapper.UserMapper;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.stereotype.Service;

import java.util.Objects;

/**
 * 用来查询数据库用户的类
 */
@Service
public class UserDetailServiceImpl implements UserDetailsService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        //1.查询用户
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.eq(User::getUserName,username);
        User user = userMapper.selectOne(queryWrapper);
        //2.没查到，抛出异常
        if (Objects.isNull(user)){
            throw new RuntimeException("用户不存在");
        }
        //3.todo 查询用户权限
        //4.返回用户信息
        return new LoginUser(user);
    }
}

二、在controller对应的service实现类里面

package com.zh.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.zh.domain.ResponseResult;
import com.zh.domain.entity.LoginUser;
import com.zh.domain.entity.User;
import com.zh.domain.vo.BlogUserLoginVo;
import com.zh.domain.vo.UserInfoVo;
import com.zh.mapper.UserMapper;
import com.zh.service.BlogLoginService;
import com.zh.utils.BeanCopyUtils;
import com.zh.utils.JwtUtil;
import com.zh.utils.RedisCache;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.stereotype.Service;

import java.util.Objects;

import static com.zh.constants.SystemConstants.LOGIN;

/**
 * 用户表(User)表服务实现类
 *
 * @author makejava
 * @since 2023-03-23 16:57:42
 */
@Service
public class BlogLoginServiceImpl extends ServiceImpl<UserMapper, User> implements BlogLoginService {

    @Autowired
    private RedisCache redisCache;
    @Autowired
    private AuthenticationManager authenticationManager;
    @Override
    public ResponseResult login(User user) {

        UsernamePasswordAuthenticationToken authenticationToken =
                new UsernamePasswordAuthenticationToken(user.getUserName(), user.getPassword());
        // 这个方法会调用UserDetailServiceImpl里面的方法去查询数据库，将结果返回给authenticate
        Authentication authenticate = authenticationManager.authenticate(authenticationToken);
        if (Objects.isNull(authenticate)){
            throw  new RuntimeException("密码错误");
        }

        //得到用户id,生成token
        LoginUser loginUser = (LoginUser) authenticate.getPrincipal();
        String userId = loginUser.getUser().getId().toString();
        String jwt = JwtUtil.createJWT(userId);
        //存入redis
        redisCache.setCacheObject(LOGIN+userId,loginUser);
        //将token和userInfo封装、返回
        UserInfoVo userInfoVo = BeanCopyUtils.copyBean(loginUser.getUser(), UserInfoVo.class);
        BlogUserLoginVo blogUserLoginVo = new BlogUserLoginVo(jwt, userInfoVo);
        return ResponseResult.okResult(blogUserLoginVo);
    }
}

三、编写JwtAuthenticationTokenFilter过滤器

这个过滤器要配置在UsernamePasswordAuthenticationFilter过滤器之前，在securityConfig配置文件中配置

package com.zh.filter;

import com.alibaba.fastjson.JSON;
import com.zh.domain.ResponseResult;
import com.zh.domain.entity.LoginUser;
import com.zh.domain.vo.BlogUserLoginVo;
import com.zh.enums.AppHttpCodeEnum;
import com.zh.utils.JwtUtil;
import com.zh.utils.RedisCache;
import com.zh.utils.WebUtils;
import io.jsonwebtoken.Claims;
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;
import java.util.Objects;

import static com.zh.constants.SystemConstants.LOGIN;

@Component
public class JwtAuthenticationTokenFilter extends OncePerRequestFilter {

    @Autowired
    private RedisCache redisCache;
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterchain) throws ServletException, IOException {
        //1.拿到请求头token
        String token = request.getHeader("token");
        if (!StringUtils.hasText(token)){
            //说明该接口不需要登录  直接放行
            filterchain.doFilter(request,response);
            return;
        }
        //2.解析token，拿到用户id
        Claims claims = null;
        try {
            claims = JwtUtil.parseJWT(token);
        } catch (Exception e) {
            e.printStackTrace();
            //超时   token非法
            ResponseResult result = ResponseResult.errorResult(AppHttpCodeEnum.NEED_LOGIN);
            WebUtils.renderString(response, JSON.toJSONString(result));
            return;
        }
        //3.从redis获取用户信息
        String userId = claims.getSubject();
        LoginUser loginUser = redisCache.getCacheObject(LOGIN + userId);
        if (Objects.isNull(loginUser)){
            //说明登录过期，需要重新登录
            ResponseResult result = ResponseResult.errorResult(AppHttpCodeEnum.NEED_LOGIN);
            WebUtils.renderString(response,JSON.toJSONString(result));
            return;
        }
        //4.存入SecurityContextHolder
        UsernamePasswordAuthenticationToken authenticationToken =
                new UsernamePasswordAuthenticationToken(loginUser, null, null);
        SecurityContextHolder.getContext().setAuthentication(authenticationToken);
        //放行
        filterchain.doFilter(request,response);
    }
}

四、securityConfig配置文件

package com.zh.config;

import com.zh.filter.JwtAuthenticationTokenFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.web.AuthenticationEntryPoint;
import org.springframework.security.web.access.AccessDeniedHandler;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }
    @Autowired
    private JwtAuthenticationTokenFilter jwtAuthenticationTokenFilter;

    @Autowired
    AuthenticationEntryPoint authenticationEntryPoint;

    @Autowired
    AccessDeniedHandler accessDeniedHandler;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                //关闭csrf
                .csrf().disable()
                //不通过Session获取SecurityContext
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS)
                .and()
                .authorizeRequests()
                // 对于登录接口 允许匿名访问
                .antMatchers("/login").anonymous()
                // 除上面外的所有请求全部不需要认证即可访问
                .anyRequest().permitAll();
        http.exceptionHandling()
                        .authenticationEntryPoint(authenticationEntryPoint)
                                .accessDeniedHandler(accessDeniedHandler);


        http.logout().disable();
        //配置JwtAuthenticationTokenFilter过滤器
http.addFilterBefore(jwtAuthenticationTokenFilter,UsernamePasswordAuthenticationFilter.class);
        //允许跨域
        http.cors();
    }

    @Bean
    public PasswordEncoder passwordEncoder(){
        return new BCryptPasswordEncoder();
    }
}