Spring Boot Application后台守护Daemon应用

本地代码启动不报错，部署到服务器之后出现如下一个错误。

系统的日志如下：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. [o.s.b.a.l.ConditionEvaluationReportLoggingListener]
2019-08-15 15:57:51.789 [restartedMain] ERROR Application run failed [org.springframework.boot.SpringApplication]
java.lang.IllegalStateException: Failed to execute CommandLineRunner
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:816)
	at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:797)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:324)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
	at com.hvisen.springboot.ApplicationLauncher.main(ApplicationLauncher.java:21)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: java.lang.IllegalStateException: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@65f0c43a has been closed already
	at org.springframework.context.support.AbstractApplicationContext.assertBeanFactoryActive(AbstractApplicationContext.java:1067)
	at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1082)
	at com.hvisen.springboot.utils.SpringUtils.getBean(SpringUtils.java:26)
	at com.hvisen.springboot.ApplicationLauncher.run(ApplicationLauncher.java:28)
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813)
	... 10 common frames omitted

程序在启动之后，自动退出了。

问题分析:
对于应用来说，无需监听，在执行完任务之后，就自动退出，这个是非常正常的情况。那该如何做才能在后台让其一直运行呢？
办法也很简单，就是利用Thread.join()功能来实现，让主线程等待当前线程的退出，当前线程一直执行，不自动退出，则可以形成一个监听状态的应用。

解决代码如下:

import com.hvisen.springboot.base.TaskStarter;
import com.hvisen.springboot.utils.SpringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Override
    public void run(String[] args) throws Exception {
        Thread.currentThread().join();
        //需要启动的代码逻辑
    }
}