springboot学习总结(七)启动执行

工作中或多或少有这样的需求,就是在项目启动后执行某个操作,一般来说listener可以满足这样的需求。但当遇到需要注入在spring容器的bean时,listener就不能满足了。这时候我们需要使用ApplicationRunner或者CommandLineRunner。这边先说个结论,用ApplicationRunner比CommandLineRunner好

(一)ApplicationRunner

@Component
public class MyFirstApplicationRunner implements ApplicationRunner, Ordered {

    @Autowired
    PeopleVo peopleVo;

    @Override
    public void run(ApplicationArguments applicationArguments) throws Exception {
        System.out.println("MyFirstApplicationRunner start");
        System.out.println("获取到的参数: " + applicationArguments.getOptionNames());
        System.out.println("获取到的参数: " + applicationArguments.getNonOptionArgs());
        System.out.println("获取到的参数: " + applicationArguments.getOptionValues("name"));
        for (String str : applicationArguments.getSourceArgs()) {
            System.out.println("获取到的参数: " + str);
        }
        System.out.println(peopleVo);
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

  启动项配置

项目启动后的输出

2019-04-16 22:00:45.375  INFO 50401 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2019-04-16 22:00:45.431  INFO 50401 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
MyFirstApplicationRunner start
命令行的keys: [name, age]
非命令行的参数值: [bbbbb, cccc]
指定命令行key名称的值: [abc]
获取到的参数: --name=abc
获取到的参数: bbbbb
获取到的参数: cccc
获取到的参数: --age=19
PeopleVo(name=vincent, age=10)

 (二)CommandLineRunner

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

    @Override
    public void run(String... strings) throws Exception {
        System.out.println("MyFirstCommandLineRunner start");
        for(String str : strings){
            System.out.println(str);
        }
    }
}

启动项配置还如上。

输入结果如下:

MyFirstCommandLineRunner start
--name=abc
bbbbb
cccc
--age=19

(三)Ordered接口和@Order注解

Ordered接口和@Order注解的作用就是限定多个实现了ApplicationRunner或者CommandLineRunner的类的执行顺序

 

 总结

ApplicationRunner和CommandLineRunner的作用几乎相同,而且ApplicationRunner的作用比CommandLineRunner好些。

 

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转载自www.cnblogs.com/vincentren/p/10720442.html
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