详解Java中日志跟踪的简单实现

%d{HH:mm:ss.SSS} [%thread] [%X{TraceId}] %-5level %logger{50} - %msg%n

public class MDCTest {

    private static final Logger log = LoggerFactory.getLogger(MDCTest.class);

    @Test
    void test() {
        MDC.put("TraceId", "123456789");
        log.info("hello {}", "world");
    }
}

logging.pattern.console=%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%X{TraceId}] %-5level %logger{50} - %msg%n

public final class TraceIdUtil {

    private static final String TRACE_ID_KEY = "TraceId";

    private TraceIdUtil() {
    }

    public static void putIfAbsent() {
        if (StrUtil.isBlank(get())) {
            put(UUID.randomUUID().toString());
        }
    }

    public static void remove() {
        if (get() != null) {
            MDC.remove(TRACE_ID_KEY);
        }
    }

    public static String get() {
        return MDC.get(TRACE_ID_KEY);
    }

    public static void put(String traceId) {
        MDC.put(TRACE_ID_KEY, traceId);
    }
}

@Component
public class LogFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, 
                         ServletResponse servletResponse, 
                         FilterChain filterChain) throws IOException, ServletException {
        TraceIdUtil.putIfAbsent();//生成trace id放入MDC中
        try {
            filterChain.doFilter(servletRequest, servletResponse);
        } finally {
            TraceIdUtil.remove();//移除MDC中的trace id
        }
    }
}

@Configuration
public class LogInterceptor implements WEBmvcConfigurer {

    @Override
    public void addInterceptors(InterceptorReGIStry registry) {
        registry.addInterceptor(new AsyncHandlerInterceptor() {
            @Override
            public boolean preHandle(httpservletRequest request, 
                                     HttpServletResponse response, 
                                     Object handler) throws Exception {
                TraceIdUtil.putIfAbsent();//生成trace id放入MDC中
                return AsyncHandlerInterceptor.super.preHandle(request, response, handler);
            }
            
            @Override
            public void afterCompletion(HttpServletRequest request, 
                                        HttpServletResponse response, 
                                        Object handler, Exception ex) throws Exception {
                TraceIdUtil.remove();//移除MDC中的trace id
                AsyncHandlerInterceptor.super.afterCompletion(request, response, handler, ex);
            }
        });
        WebMvcConfigurer.super.addInterceptors(registry);
    }
}

@RestController
@RequestMapping("/api/user")
@Slf4j
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{userId}")
    public UserDto queryUser(@PathVariable Long userId) {
        log.info("query user by id:{}", userId);
        UserDto user = userService.query(userId);
        log.info("query user result:{}", user);
        return user;
    }
}