Spring各种注解的含义及用法(持续更新)

ApplicationContext context = new AnnotationConfigApplicationContext(TestConfiguration.class);

如果加载spring-context.xml文件：
ApplicationContext context = new ClassPathXmlApplicationContext("spring-context.xml");

@Param

List<Map> getTimeLineColumn(@Param("cbIds") List<String> cbIds)throws Exception;

xml中示例：

<select id="getTimeLineColumn" resultType="Map">
    select cu.USERNAME,cu.ID
    from CASEBANK cb
    join CASEUSER cu on cb.CUID=cu.id
    WHERE cb.ID in
    <foreach collection="cbIds" item="cbid" open="(" separator="," close=")">
        #{cbid}
    </foreach>
    GROUP BY cu.ID,cu.USERNAME
    ORDER BY id
</select>

2.SpringBoot中常见注解

@RestController

@SpringBootApplication

@ImportResource

@PathVaribale

@RestController
public class HelloController {
 
  @RequestMapping(value="/hello/{id}",method= RequestMethod.GET)
  public String sayHello(@PathVariable("id") Integer id){
    return "id:"+id;
  }
}

@RequestParam

@RestController
public class HelloController {
 
  @RequestMapping(value="/hello",method= RequestMethod.GET)
  public String sayHello(@RequestParam("id") Integer id){
    return "id:"+id;
  }
}

@RequestBody

@RequestParam 和 @RequestBody 一起使用在接口上时

@PostMapping(value = ConstScheduleUrl.COMMON_ADDACCESSORYLIST)
public ResponseResult addAccessoryList(@RequestParam("workPlanId") String workPlanId,@RequestBody ScheduleCommonWorkPlanVO commonWorkPlanVO){
    commonWorkPlanCodeService.commonHandleAccessory(commonWorkPlanVO,workPlanId);
    return ResponseResult.success();
}

@EnableScheduling

@Scheduled

@EnableCaching

//将缓存保存进andCache，并使用参数中的userId加上一个字符串(这里使用方法名称)作为缓存的key     
@Cacheable(value="andCache",key="#userId + ‘findById‘")    
public SystemUser findById(String userId) {    
    SystemUser user = (SystemUser) dao.findById(SystemUser.class, userId);          
    return user ;           
}

//将缓存保存进andCache，并当参数userId的长度小于32时才保存进缓存，默认使用参数值及类型作为缓存的key    
@Cacheable(value="andCache",condition="#userId.length < 32")    
public boolean isReserved(String userId) {    
    System.out.println("hello andCache"+userId);    
    return false;    
}    

@CacheConfig

//定义该类中的所有缓存在CACHE_SYS_PAPER 里
@Service
@CacheConfig(cacheNames = { CacheConstants.CACHE_SYS_PAPER })
public class ScheduleTrainPaperService {
    ...
}

@Cacheable

//SpEL方式定义key
CacheConstants.CACHE_ROOT_METHOD_NAME_ID="#root.methodName + #id"

@Cacheable(key = CacheConstants.CACHE_ROOT_METHOD_NAME_ID ,sync =true)
public ScheduleTrainOption get(Integer id) {
   return trainOptionMapper.get(id);
}

@CacheEvict

@CahePut

@EnableTransactionManagement

@MapperScan

@SpringBootApplication
@MapperScan("com.lz.water.monitor.mapper")

//也可以同时扫描多个包
@SpringBootApplication  
@MapperScan({"com.kfit.demo","com.kfit.user"})  

//如果mapper类没有在Spring Boot主程序可以扫描的包或者子包下面，可以使用如下方式进行配置
@SpringBootApplication  
@MapperScan({"com.kfit.*.mapper","org.kfit.*.mapper"})  

@ConfigurationProperties

@Component
@ConfigurationProperties(prefix = "com.example.demo")

通过@Bean的方式进行声明,这里我们加在启动类即可,代码如下

@Bean
@ConfigurationProperties(prefix = "com.example.demo")

prefix 全部要改成小写，不可以配合@value 使用会报错

java.lang.IllegalArgumentException: Could not resolve placeholder ‘defaultPoints‘ in value "${defaultPoints}"

@ProtertySource

@PropertySource("classpath:jdbc.properties")
@Value(${jdbc.driver})
private String driver;

也可以配合@ConfigurationProperties 使用

@ExceptionHandler

@ControllerAdvice

@RestControllerAdvice

@RestControllerAdvice
public class RmcpExceptionHandler {
    private final static Logger logger = LoggerFactory.getLogger(RmcpExceptionHandler.class);

    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public ResponseResult handle(Exception e) {
        ResponseResult result = new ResponseResult();
        if (e instanceof RmcpException) {
            // 系统自定义异常
            ....
        } else if (e instanceof ConstraintViolationException) {
            ....
        } else if (e instanceof MethodArgumentTypeMismatchException) {
           ...
        } else if (e instanceof MethodArgumentNotValidException){
            ...
        }
        else if (e instanceof HttpMessageNotReadableException) {
            ...
        } else {
            // 未知异常
            ...
        }

        e.printStackTrace();
        return result;
    }
}

@ResponseStatus

@ConditionalOnMissingBean

@Bean
    @ConditionalOnMissingBean(name = "imageValidateCodeGenerator")
    public ValidateCodeGenerator imageValidateCodeGenerator() {
        ImageCodeGenerator codeGenerator = new ImageCodeGenerator();
        codeGenerator.setSecurityProperty(securityProperties);
        return codeGenerator;
    }

测试发现， @ConditionOnMissingBean 只能在@Bean 注释的方法上使用，不能再@Component 注释的类上使用

@PostConstruct

@PreDestroy

@Transactional

PROPAGATION_REQUIRES_NEW和PROPAGATION_NESTED的区别

REQUIRES_NEW：启动一个新的，不依赖环境的“内部”事务，这个事务将被完全commited或rolled back 而不依赖于外部事务，它拥有自己的隔离范围，自己的锁等等，当内部事务开始执行时，外部事务将被挂起，内部事务结束时，外部事务将继续执行。

NESTED：如果外部事务commit，嵌套事务也会被commit；如果外部事务roll back，嵌套事务也会被 roll back。

开始一个嵌套的事务，它是已经存在事务的一个真正的子事务，嵌套事务开始执行时，它将取得一个savepoint，如果这个嵌套事务失败，我们将回滚到此savepoint，嵌套事务是外部事务的一部分，只有外部事务结束后它才会被提交