Core Spring Framework Annotations
@Component 跟 @Service @Controller @Repository 有什么区别？
- 后三者基本都是 @Component 在不同层次的别名，服务层、接口层、持久层。
- Difference between @Component, @Service, @Controller, and @Repository in Spring : https://javarevisited.blogspot.com/2017/11/difference-between-component-service.html
- @Component vs @Repository and @Service in Spring | Baeldung : https://www.baeldung.com/spring-component-repository-service
- java - What's the difference between @Component, @Repository & @Service annotations in Spring? - Stack Overflow : https://stackoverflow.com/questions/6827752/whats-the-difference-between-component-repository-service-annotations-in
@Bean 和 @Component 是不是同一种东西？是不同的概念！
- java - Spring: @Component versus @Bean - Stack Overflow : https://stackoverflow.com/questions/10604298/spring-component-versus-bean
- @Component 和 @Bean 的区别 : https://blog.csdn.net/qq_38534144/article/details/82414201
Same is true for @Service and @Repository annotation, they are a specialization of @Component in service and persistence layer. A Spring bean in the service layer should be annotated using @Service instead of @Component annotation and a spring bean in the persistence layer should be annotated with @Repository annotation.
By using a specialized annotation we hit two birds with one stone. First, they are treated as Spring bean and second you can put special behavior required by that layer.
References
Example : @ActiveProfile in Tests
- SomeMessageReceiver.java
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;
@Profile("mq")
@Component
public class SomeMessageReceiver {
// ……
}- MqTest.java
import lombok.extern.slf4j.Slf4j;
import org.junit.runner.RunWith;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xyz.icehe.java.demo.main.Application;
@ActiveProfiles("maxq")
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = Application.class)
@Slf4j
public class MqTest {
@Autowired
private SomeMessageReceiver someMessageReceiver;
@Test
public void sendMsg() {
// ……
}
}总结：lombok 的 @Data 注释导致的问题 (详见微博)
- 在@Value注解中为String类型的字段设置null值 | 鸟窝 : https://colobu.com/2015/09/09/set-null-for-a-string-property-by-Value/
- fastJSON中@JSONField注解详解 - 明洋的专栏 - CSDN博客 : https://blog.csdn.net/yaomingyang/article/details/79861281
- FastJson中@JSONField注解使用 - 奔跑的蜗牛的博客 - CSDN博客 : https://blog.csdn.net/u011425751/article/details/51219242 (感觉写得不太好，费解)
- 有空自己写代码实验一下好了
- JSON.toJSONString中序列化空字符串遇到的坑 - 极客分享Geek-Share.com : https://www.geek-share.com/detail/2750512280.html
- fastjson SerializerFeature详解 - 孤天浪雨 - CSDN博客 : https://blog.csdn.net/u010246789/article/details/52539576
- Jackson Annotations : http://tutorials.jenkov.com/java-json/jackson-annotations.html#jsoncreator
- Jackson Annotation Examples : https://www.baeldung.com/jackson-annotations