首先看实现了两个接口运行的顺序结果:
My1:
package com.example.commandlinerunner; import lombok.extern.java.Log; import org.springframework.boot.CommandLineRunner; import org.springframework.core.annotation.Order; import org.springframework.core.annotation.OrderUtils; import org.springframework.stereotype.Component; import java.util.Arrays; /** * Created by WangYx on 2017/9/14. */ @Component @Order(6) @Log public class MyCmdLinerRunner1 implements CommandLineRunner { @Override public void run(String... args) throws Exception { log.info("MyCmdLinerRunner1:order = " + OrderUtils.getOrder(this.getClass())+" :args = " + Arrays.toString(args)); } private String getStacks(){ StringBuilder sb = new StringBuilder(); StackTraceElement[] elements = Thread.currentThread().getStackTrace(); sb.append("=============\n"); for (int i = 0 ; i < elements.length ; i++){ sb.append(elements[i]).append("\n"); } return sb.toString(); } } My2:
package com.example.commandlinerunner; import lombok.extern.java.Log; import org.springframework.boot.CommandLineRunner; import org.springframework.core.annotation.Order; import org.springframework.core.annotation.OrderUtils; import org.springframework.stereotype.Component; import java.util.Arrays; /** * Created by WangYx on 2017/9/14. */ @Component @Order(5) @Log public class MyCmdLinerRunner2 implements CommandLineRunner { @Override public void run(String... args) throws Exception { log.info("MyCmdLinerRunner2:order = " + OrderUtils.getOrder(this.getClass())+" :args = " + Arrays.toString(args)); } } 主函数:
package com.example.commandlinerunner; /** * 通过CommandLineRunner,可在所有Spring Bean和 ApplicationContext被创建后执行一些可以访问命令行参数的任务。 * 如想指定多个CommandLineRunnerBean的执行顺序, * 可以实现org.springframework.core.Ordered接口 * 或添加org.springframework.core.annotation.Order注解 */ import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class CommandlinerunnerApplication { public static void main(String[] args) { SpringApplication.run(CommandlinerunnerApplication.class, args); } } /** * org.springframework.core.annotation.AnnotationAwareOrderComparator负责对CommandLineRunnerBean进行排序。排序规则为: 如果有一方是org.springframework.core.PriorityOrdered接口实现,而另一方不是,则PriorityOrdered接口实现一方获胜; 检查org.springframework.core.Ordered接口或 org.springframework.core.annotation.Order 注解获得order,值小者胜; 其他没有order的则置为Ordered.LOWEST_PRECEDENCE,顺序不定。 在上述测试中,MyCmdLineRunner2的order为5,MyCmdLineRunner1的order为6,因此MyCmdLineRunner2在MyCmdLineRunner1之前执行。 Application的demo1和demo2方法设置了@order注解,但是调试可知lamda表达式生成类并没有@order注解信息,因此执行顺序排在后面。 这是需要注意的地方。此外,Bean初始化顺序跟CommandLineRunner执行顺序也没有关系。 */