SpringBoot之Order注解启动顺序

order的规则：

order的值越小，优先级越高
order如果不标注数字，默认最低优先级，因为其默认值是int最大值
该注解等同于实现Ordered接口getOrder方法，并返回数字。

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD})
@Documented
public @interface Order {

/**
* The order value.
* <p>Default is {@link Ordered#LOWEST_PRECEDENCE}.
* @see Ordered#getOrder()
*/
int value() default Ordered.LOWEST_PRECEDENCE;

}

int LOWEST_PRECEDENCE = Integer.MAX_VALUE;
@Aspect
@Component
public class DataSourceAspect implements Ordered {

@Override
public int getOrder() {
return 1;
}

}
见下：

OrderRunner1.java

@Component
@Order(1)
public class OrderRunner1 implements CommandLineRunner {

@Override
public void run(String... args) throws Exception {
System.out.println("The OrderRunner1 start to initialize ...");
}
}
 OrderRunner2.java

@Component
@Order(2)
public class OrderRunner2 implements CommandLineRunner {

@Override
public void run(String... args) throws Exception {
System.out.println("The OrderRunner2 start to initialize ...");
}
}
 Runner.java

@Component
public class Runner implements CommandLineRunner {

@Override
public void run(String... args) throws Exception {
System.out.println("The Runner start to initialize ...");
}
}
@SpringBootApplication
public class CommandLineRunnerApplication {

public static void main(String[] args) {
System.out.println("The service to start.");
SpringApplication.run(CommandLineRunnerApplication.class, args);
System.out.println("The service has started.");
}
}

它们的启动日志：

The service to start.
...
...
The OrderRunner1 start to initialize ...
The OrderRunner2 start to initialize ...
The Runner start to initialize ...
The service has started.
 
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作者：jiangxwa
来源：CSDN
原文：https://blog.csdn.net/jiangxwa/article/details/87892577
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