23.SpringApplication
SpringApplication类使用main()方法来方便的方式来引导Spring application的启动.在许多情况下，你可以委托给静态SpringApplication.run方法:
public static void main(String[] args) {
SpringApplication.run(MySpringConfiguration.class, args);
}
一般的启动失败大都是因为端口(8080)被占用
启动打印的横幅可以自定义
| Variable | Description |
|---|---|
${application.version} |
The version number of your application as declared in MANIFEST.MF. For example Implementation-Version: 1.0 is printed as 1.0. |
${application.formatted-version} |
The version number of your application as declared in MANIFEST.MF formatted for display (surrounded with brackets and prefixed with v). For example (v1.0). |
${spring-boot.version} |
The Spring Boot version that you are using. For example 1.5.9.RELEASE. |
| ${spring-boot.formatted-version} | The Spring Boot version that you are using formatted for display (surrounded with brackets and prefixed with v). For example (v1.5.9.RELEASE). |
${Ansi.NAME} (or ${AnsiColor.NAME}, ${AnsiBackground.NAME}, ${AnsiStyle.NAME}) |
Where NAME is the name of an ANSI escape code. See AnsiPropertySource for details. |
${application.title} |
The title of your application as declared in MANIFEST.MF. For exampleImplementation-Title: MyApp is printed as MyApp. |
yaml 可以禁用横幅
spring: main: banner-mode: "off"
Accessing application arguments
访问应用程序参数
可以注入一个org.springframework.boot.ApplicationArgumentsbean,来访问程序参数.
import org.springframework.boot.*
import org.springframework.beans.factory.annotation.*
import org.springframework.stereotype.*
@Component
public class MyBean {
@Autowired //注入args[]
public MyBean(ApplicationArguments args) {
boolean debug = args.containsOption("debug");
List<String> files = args.getNonOptionArgs();
// if run with "--debug logfile.txt" debug=true, files=["logfile.txt"]
}
}
使用ApplicationRunner或CommandLineRunner
你可以通过实现ApplicationRunner 和CommandLineRunner 这两个接口来在启动时运行一些特殊的代码once,这两个接口都以相同的方式工作,并提供一个run方法,将在SpringApplication.run() 完成之前调用.
CommandLineRunner 接口使用一个简单的String[] 提供对应用程序参数的访问,而ApplicationRunner 则使用ApplicationArguments 接口
import org.springframework.boot.*
import org.springframework.stereotype.*
@Component
public class MyBean implements CommandLineRunner {
public void run(String... args) {
// Do something...
}
}
程序退出
如果bean 在SpringApplication.exit() 调用时希望返回一个特定的退出代码，它们可以实现org.springframework.boot.ExitCodeGenerator 接口.这个退出代码然后可以被传递给System.exit()作为状态代码返回它.
@SpringBootApplication
public class ExitCodeApplication {
@Bean
public ExitCodeGenerator exitCodeGenerator() {
return new ExitCodeGenerator() {
@Override
public int getExitCode() {
return 42;
}
};
}
public static void main(String[] args) {
System.exit(SpringApplication .exit(SpringApplication.run(ExitCodeApplication.class, args)));
}
}
