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 <b>public</b> <b>class</b> DemoApplication implements CommandLineRunner { <b>private</b> <b>final</b> Logger logger = LoggerFactory.getLogger(DemoApplication.<b>class</b>); <b>public</b> <b>static</b> <b>void</b> main(String args) { SpringApplication.run(DemoApplication.<b>class</b>, args); } @Override <b>public</b> <b>void</b> run(String... strings) throws Exception { .... } }
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) <b>public</b> <b>class</b> AnotherDatabaseLoader implements CommandLineRunner { @Component @Order(2) <b>public</b> <b>class</b> DataLoader implements CommandLineRunner {
另外一种在主应用的写法:
@SpringBootApplication <b>public</b> <b>class</b> UnsplashApplication { <b>public</b> <b>static</b> <b>void</b> main(String args) { SpringApplication.run(UnsplashApplication.<b>class</b>, args); } @Bean CommandLineRunner runner(){ <b>return</b> args -> { System.out.println(<font>"CommandLineRunner running in the UnsplashApplication class..."</font><font>); }; } } </font>