SpringBoot 项目启动慢原因分析

# 现象

```
// 错误信息
[root@centos-7-ovs01 ~]# java -jar demo-0.0.1-SNAPSHOT.jar 
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.1)

2021-01-11 17:35:38.037  WARN 1999 --- [           main] o.s.boot.StartupInfoLogger               : InetAddress.getLocalHost().getHostName() took 15012 milliseconds to respond. Please verify your network configuration.
2021-01-11 17:35:53.154  INFO 1999 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication v0.0.1-SNAPSHOT using Java 1.8.0_272 on centos-7-ovs01 with PID 1999 (/root/demo-0.0.1-SNAPSHOT.jar started by root in /root)
2021-01-11 17:35:53.155  INFO 1999 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2021-01-11 17:35:54.409  INFO 1999 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 57.276 seconds (JVM running for 58.997);
```

注意其中出现的`InetAddress.getLocalHost().getHostName() took 15012 milliseconds to respond. Please verify your network configuration.`。

大意是主机名地址解析花了5秒多，请检查你的网络配置(hostname可能需要加入`/etc/hosts`中)。

# 原因

SpringBoot启动时需要解析HostName，正常情况下是hostname是不需要手动配置到`/etc/hosts`中的。

# 解决办法

修改`/etc/hosts`文件。

![](/media/202204/2022-04-29_163437_499979.png)

![](/media/202204/2022-04-29_163415_521383.png)