使用SpringBoot+AOP实现可插拔式日志的示例代码

下面是使用SpringBoot+AOP实现可插拔式日志的完整攻略。

什么是SpringBoot+AOP

Spring AOP（Aspect Oriented Programming）是Spring框架中的一个重要模块，用于将额外的行为（横切逻辑）注入到系统中的特定点。SpringBoot是Spring框架的一个特殊版本，通过预先配置好常用的Bean并提供自动配置的功能，简化了使用Spring框架的流程。SpringBoot+ AOP就是指在SpringBoot框架中使用AOP模块实现横切的功能。

使用SpringBoot+AOP实现可插拔式日志的示例代码

什么是可插拔式日志？

可插拔式日志是指系统中的日志在架构层面进行抽象封装，使用独立的模块或组件实现具体的日志记录功能。通过组件化的方式来实现日志记录，可以使日志的记录方式与应用程序的其它部分相互独立，并且可以通过更换组件的方式进行日志存储、过滤等高级功能调整，从而实现更加灵活、可扩展的日志记录方案。

实现步骤

下面介绍如何使用SpringBoot+AOP实现可插拔式日志的示例代码，包含以下步骤：

1. 定义日志接口并实现具体的日志记录功能
2. 创建切面类，定义切点及切入点
3. 使用@Aspect注解将切面类定义为切面
4. 在代码中使用注入AOP之后的Bean，触发切面记录日志

示例1：将日志输出到控制台

第1步：定义日志接口并实现具体的日志记录功能

public interface LoggerService {

    void trace(String msg);

    void debug(String msg);

    void info(String msg);

    void warn(String msg);

    void error(String msg);
}

@Component
public class ConsoleLoggerServiceImpl implements LoggerService {

    public void trace(String msg) {
        System.out.println("[TRACE] " + msg);
    }

    public void debug(String msg) {
        System.out.println("[DEBUG] " + msg);
    }

    public void info(String msg) {
        System.out.println("[INFO] " + msg);
    }

    public void warn(String msg) {
        System.out.println("[WARN] " + msg);
    }

    public void error(String msg) {
        System.out.println("[ERROR] " + msg);
    }
}

第2步：创建切面类，定义切点及切入点

@Aspect
@Component
public class LoggerAspect {

    private static final String EXECUTION = "execution(* com.example.demo.controller.*.*(..))";

    @Autowired
    private LoggerService loggerService;

    @Pointcut(EXECUTION)
    private void logPointcut() {}

    @Before("logPointcut()")
    public void logBeforeAdvice(JoinPoint joinPoint) {
        loggerService.debug("Start to execute method: " + joinPoint.getSignature().getName());
    }

    @AfterReturning(pointcut = "logPointcut()", returning = "result")
    public void logAfterAdvice(JoinPoint joinPoint, Object result) {
        loggerService.debug("Method " + joinPoint.getSignature().getName() + " returns with: " + result);
    }

    @AfterThrowing(pointcut = "logPointcut()", throwing = "e")
    public void logAfterThrowingAdvice(JoinPoint joinPoint, Throwable e) {
        loggerService.error("Method " + joinPoint.getSignature().getName() + " threw an exception: " + e.getMessage());
    }
}

第3步：使用@Aspect注解将切面类定义为切面

@SpringBootApplication
@EnableAspectJAutoProxy
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

第4步：在代码中使用注入AOP之后的Bean，触发切面记录日志

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

    @Autowired
    private UserService userService;

    private static final Logger logger = LoggerFactory.getLogger(UserController.class);

    @PostMapping("/add")
    public User addUser(@RequestBody User user) {
        logger.info("Add user: " + user);
        return userService.addUser(user);
    }

    @GetMapping("/list")
    public List<User> listUsers() {
        logger.info("List all users");
        return userService.listUsers();
    }

    @GetMapping("/{id}")
    public User getUser(@PathVariable long id) {
        logger.info("Get user: " + id);
        return userService.getUser(id);
    }

    @PutMapping("/{id}")
    public User updateUser(@PathVariable long id, @RequestBody User user) {
        logger.info("Update user: " + id + " to " + user);
        return userService.updateUser(id, user);
    }

    @DeleteMapping("/{id}")
    public void deleteUser(@PathVariable long id) {
        logger.info("Delete user: " + id);
        userService.deleteUser(id);
    }
}

示例2：将日志输出到文件

第1步：定义日志接口并实现具体的日志记录功能

public interface LoggerService {

    void trace(String msg);

    void debug(String msg);

    void info(String msg);

    void warn(String msg);

    void error(String msg);
}

@Component
public class FileLoggerServiceImpl implements LoggerService {

    private static final Logger logger = LoggerFactory.getLogger(FileLoggerServiceImpl.class);

    public void trace(String msg) {
        logger.trace(msg);
    }

    public void debug(String msg) {
        logger.debug(msg);
    }

    public void info(String msg) {
        logger.info(msg);
    }

    public void warn(String msg) {
        logger.warn(msg);
    }

    public void error(String msg) {
        logger.error(msg);
    }
}

第2步：创建切面类，定义切点及切入点

@Aspect
@Component
public class LoggerAspect {

    private static final String EXECUTION = "execution(* com.example.demo.controller.*.*(..))";

    @Autowired
    private LoggerService loggerService;

    @Pointcut(EXECUTION)
    private void logPointcut() {}

    @Before("logPointcut()")
    public void logBeforeAdvice(JoinPoint joinPoint) {
        loggerService.debug("Start to execute method: " + joinPoint.getSignature().getName());
    }

    @AfterReturning(pointcut = "logPointcut()", returning = "result")
    public void logAfterAdvice(JoinPoint joinPoint, Object result) {
        loggerService.debug("Method " + joinPoint.getSignature().getName() + " returns with: " + result);
    }

    @AfterThrowing(pointcut = "logPointcut()", throwing = "e")
    public void logAfterThrowingAdvice(JoinPoint joinPoint, Throwable e) {
        loggerService.error("Method " + joinPoint.getSignature().getName() + " threw an exception: " + e.getMessage());
    }
}

第3步：使用@Aspect注解将切面类定义为切面

@SpringBootApplication
@EnableAspectJAutoProxy
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

第4步：在代码中使用注入AOP之后的Bean，触发切面记录日志

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

    @Autowired
    private UserService userService;

    private static final Logger logger = LoggerFactory.getLogger(UserController.class);

    @PostMapping("/add")
    public User addUser(@RequestBody User user) {
        logger.info("Add user: " + user);
        return userService.addUser(user);
    }

    @GetMapping("/list")
    public List<User> listUsers() {
        logger.info("List all users");
        return userService.listUsers();
    }

    @GetMapping("/{id}")
    public User getUser(@PathVariable long id) {
        logger.info("Get user: " + id);
        return userService.getUser(id);
    }

    @PutMapping("/{id}")
    public User updateUser(@PathVariable long id, @RequestBody User user) {
        logger.info("Update user: " + id + " to " + user);
        return userService.updateUser(id, user);
    }

    @DeleteMapping("/{id}")
    public void deleteUser(@PathVariable long id) {
        logger.info("Delete user: " + id);
        userService.deleteUser(id);
    }
}

以上就是使用SpringBoot+AOP实现可插拔式日志的示例代码。