Springboot 注解@Bean、@Component、 @Service、 @Repository 和 @Controller

@Bean、@Component、 @Service、 @Repository 、 @Controller

@Bean：表示一个方法实例化、配置或者初始化一个Spring IoC容器管理的新对象。

@Data
@EnableConfigurationProperties
@Configuration
@ConfigurationProperties(prefix = "redis.cache")
public class RedisCacheConfig {
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
        return new RedisCacheManager(
                RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory),
                this.getRedisCacheConfigurationWithTtl(600),
                this.getRedisCacheConfigurationMap()
        );
    }
}

@Component: 自动被component扫描。表示被注解的类会自动被component扫描

@Component
public class RedisLimiterUtils {
    @Resource
    RedisTemplate<Object, Object> redisTemplate;
    @Resource(name = "stringRedisTemplate")
    ValueOperations<String, String> ops;
    @Resource(name = "redisTemplate")
    ValueOperations<Object, Object> objOps;

public void saveObject(String key, Object obj, long timeout) {
        redisUtil.set(key, obj, timeout);
    }


    public void saveObject(String key, Object obj) {
        redisUtil.set(key, obj);
    }


    public Object getObject(String key) {
        return redisUtil.get(key);
    }


    public void removeObject(String key) {
        redisUtil.del(key);
    }


}

@Repository: 用于持久层，主要是数据库存储库。

@Repository
public interface NginxLogDao extends ElasticsearchRepository<NinxLogDocument, String> {

}

@Service: 表示被注解的类是位于业务层的业务component。

@Slf4j
@Service
public class ValidateCodeServiceImpl implements ValidateCodeService {

@Autowired
  private RedisTemplate<String, Object> redisTemplate;

  /**
   * 保存用户验证码，和randomStr绑定
   * @param deviceId
   *            客户端生成
   * @param imageCode
   *            验证码信息
   */
  @Override
  public void saveImageCode(String deviceId, String imageCode) {
      String text = imageCode.toLowerCase().toString();
      redisTemplate.execute(new RedisCallback<String>() {
          @Override
          public String doInRedis(RedisConnection connection) throws DataAccessException {
              // redis info
              connection.set(buildKey(deviceId).getBytes(), imageCode.getBytes());
              connection.expire(buildKey(deviceId).getBytes(), 60*5);
              connection.close();
              return "";
          }
      });

  }

  /**
   * 获取验证码
   * @param deviceId
   *            前端唯一标识/手机号
   */
  @Override
  public String getCode(String deviceId)  {
      String code = "" ;
      try {
          code = redisTemplate.execute(new RedisCallback<String>() {
              @Override
              public String doInRedis(RedisConnection connection) throws DataAccessException {
                  // redis info
                  byte[] temp = "".getBytes();
                  temp = connection.get(buildKey(deviceId).getBytes()) ;
                  connection.close();
                  return new String(temp);
              }
          });
      } catch (Exception e) {
          throw new AuthenticationException("验证码不存在"){};
      }
      return code ;
  }

  /**
   * 删除验证码
   * @param deviceId
   *            前端唯一标识/手机号
   */
  @Override
  public void remove(String deviceId) {
      redisTemplate.execute(new RedisCallback<String>() {
          @Override
          public String doInRedis(RedisConnection connection) throws DataAccessException {
              // redis info
              connection.del(buildKey(deviceId).getBytes());
              connection.close();
              return "";
          }
      });
  }

  /**
   * 验证验证码
   */
  @Override
  public void validate(HttpServletRequest request) {
      String deviceId = request.getParameter("deviceId");
      if (StringUtils.isBlank(deviceId)) {
          throw new AuthenticationException("请在请求参数中携带deviceId参数"){};
      }
      String code = this.getCode(deviceId);
      String codeInRequest;
      try {
          codeInRequest = ServletRequestUtils.getStringParameter(request, "validCode");
      } catch (ServletRequestBindingException e) {
          throw new AuthenticationException ("获取验证码的值失败"){};
      }
      if (StringUtils.isBlank(codeInRequest)) {
          throw new AuthenticationException ("请填写验证码"){};
      }

      if (code == null) {
          throw new AuthenticationException ("验证码不存在或已过期"){};
      }

      if (!StringUtils.equalsIgnoreCase(code, codeInRequest)) {
          throw new AuthenticationException ("验证码不正确"){};
      }
      this.remove(deviceId);
  }

  private String buildKey(String deviceId) {
      return "DEFAULT_CODE_KEY:" + deviceId;
  }
}

@Controller:表明被注解的类是控制component，主要用于展现层。

@Controller
@Api(tags = "REDIS API")
@RequestMapping("/redis")
public class RedisController {
   @Autowired
    private RedisTemplate<String,Object> redisTemplate ;
 @ResponseBody
    @RequestMapping("/memoryInfo")
    @LogAnnotation(module="auth-server",recordRequestParam=false)
    public String getMemoryInfo() {
        Map<String, Object> map = new HashMap<>();
        Object o = redisTemplate.execute(new RedisCallback() {
            @Override
            public Object doInRedis(RedisConnection connection) throws DataAccessException {
                return connection.info("memory").get("used_memory");
            }
        });
        map.put("used_memory", o);
        map.put("create_time", System.currentTimeMillis());
        return JSON.toJSONString(map);
    }

}

@Bean与@Component区别
@Component是 spring 2.5引入的，为了摆脱通过classpath扫描根据xml方式定义的bean的方式.

@Bean是spring 3.0 引入的，和 @Configuration一起工作，为了摆脱原先的xml和java config方式。

Spring管理Bean方式有两种，一种是注册Bean，一种装配Bean。
可以通过三种方式实现bean管理，一使用自动配置的方式、二使用JavaConfig的方式、三使用XML配置的方式。

@Component
@Data
public class User{
    private String name = "tom";
}

@Bean 需要在配置类中使用，即类上需要加上@Component或者@Configuration注解，通常加上@Configuration。 @Bean的用法在这里。

@Configuration
public class AppConfig {

    @Bean
    public TransferServiceImpl transferService() {
        return new TransferServiceImpl();
    }
}

@Autowired
private TransferService transferService;

@Component与@Service区别
目前基本没有区别。@Service是一种具体的@Component

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Component
public @interface Service {
   String value() default "";
}

注解一览
@Autowired
@Qualifier
@Primary
@Resource
@Bean
@Component
@Service
@Repository
@Controller