CommandLineRunner是一个带有run方法的简单spring引导接口。Spring Boot启动后将自动调用实现CommandLineRunner接口的所有bean的run方法。
Command Line Runner在加载应用程序上下文之后以及Spring Application run方法完成之前执行,相当于你的应用的初始化过程,一般用来实现一些数据预先加载或预先处理。
@SpringBootApplication public class DemoApplication implements CommandLineRunner {
private final Logger logger = LoggerFactory.getLogger(DemoApplication.class);
public static void main(String args) { SpringApplication.run(DemoApplication.class, args); }
@Override public void run(String... strings) throws Exception { .... }
}
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上面的run方法参数是命令行参数,使用java -jar 启动这个应用的命令行参数。
如果有多个命令行运行器,可以进行排序:
@Component @Order(1) public class AnotherDatabaseLoader implements CommandLineRunner {
@Component @Order(2) public class DataLoader implements CommandLineRunner {
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另外一种在主应用的写法:
@SpringBootApplication public class UnsplashApplication { public static void main(String args) { SpringApplication.run(UnsplashApplication.class, args); } @Bean CommandLineRunner runner(){ return args -> { System.out.println("CommandLineRunner running in the UnsplashApplication class..."); }; } }
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