最近springboot启动后一小会就自动停止，没提示具体报错，只有提示：

Disconnected from the target VM, address: '127.0.0.1:60011', transport: 'socket'

Process finished with exit code 0

我的解决办法：

原来是没有加log4j的配置文件，导致有错误没有提示。在resources目录下新建文件：log4j.properties。复制内容：

log4j.rootLogger=WARN, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n

重新启动项目，看到报错：

2020-10-30 11:41:49,236 ERROR [org.springframework.boot.SpringApplication] - Application run failed
java.lang.IllegalStateException: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:83)
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperTransporter.createZookeeperClient(CuratorZookeeperTransporter.java:26)
	at org.apache.dubbo.remoting.zookeeper.support.AbstractZookeeperTransporter.connect(AbstractZookeeperTransporter.java:68)
	at org.apache.dubbo.remoting.zookeeper.ZookeeperTransporter$Adaptive.connect(ZookeeperTransporter$Adaptive.java)
	at org.apache.dubbo.configcenter.support.zookeeper.ZookeeperDynamicConfiguration.<init>(ZookeeperDynamicConfiguration.java:62)
	at org.apache.dubbo.configcenter.support.zookeeper.ZookeeperDynamicConfigurationFactory.createDynamicConfiguration(ZookeeperDynamicConfigurationFactory.java:37)
	at org.apache.dubbo.configcenter.AbstractDynamicConfigurationFactory.getDynamicConfiguration(AbstractDynamicConfigurationFactory.java:33)
	at org.apache.dubbo.config.AbstractInterfaceConfig.getDynamicConfiguration(AbstractInterfaceConfig.java:315)
	at org.apache.dubbo.config.AbstractInterfaceConfig.prepareEnvironment(AbstractInterfaceConfig.java:290)
	at org.apache.dubbo.config.AbstractInterfaceConfig.startConfigCenter(AbstractInterfaceConfig.java:280)
	at org.apache.dubbo.config.AbstractInterfaceConfig.lambda$null$7(AbstractInterfaceConfig.java:636)
	at java.util.Optional.orElseGet(Optional.java:267)
	at org.apache.dubbo.config.AbstractInterfaceConfig.lambda$useRegistryForConfigIfNecessary$8(AbstractInterfaceConfig.java:620)
	at java.util.Optional.ifPresent(Optional.java:159)
	at org.apache.dubbo.config.AbstractInterfaceConfig.useRegistryForConfigIfNecessary(AbstractInterfaceConfig.java:618)
	at org.apache.dubbo.config.AbstractInterfaceConfig.checkRegistry(AbstractInterfaceConfig.java:208)
	at org.apache.dubbo.config.ServiceConfig.checkAndUpdateSubConfigs(ServiceConfig.java:303)
	at org.apache.dubbo.config.ServiceConfig.export(ServiceConfig.java:370)
	at org.apache.dubbo.config.spring.ServiceBean.export(ServiceBean.java:336)
	at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:114)
	at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:60)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403)
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360)
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:897)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at com.tuling.dubbo.boot.BootServerApplication.main(BootServerApplication.java:12)
	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: zookeeper not connected
	at org.apache.dubbo.remoting.zookeeper.curator.CuratorZookeeperClient.<init>(CuratorZookeeperClient.java:80)
	... 38 more

原来是zookeeper服务没有启动，连接失败，启动zookeeper的服务就好了。

没有log4j的配置文件就没有输出报错，配置好log4j的配置文件就能看到错误。

---

如果我的办法没有解决，网上也有其他朋友的解决办法不妨试试：

其他方法

方法一：

加maven依赖：

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
</dependency>

方法二：

maven注释掉包：spring-boot-starter-tomcat

<!--
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-tomcat</artifactId>
  <scope>provided</scope>
</dependency>
-->