场景：在Linux服务器部署项目使用的是mybatisPlus，启动时提示java.net.UnknownHostException: tzb.xysjk: tzb.xysjk: 系统错误

Caused by: com.baomidou.mybatisplus.core.exceptions.MybatisPlusException: java.net.UnknownHostException: tzb.xyttt: tzb.xyttt: 系统错误
	at com.baomidou.mybatisplus.core.toolkit.Sequence.getLocalHost(Sequence.java:100) ~[mybatis-plus-core-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.core.toolkit.Sequence.<init>(Sequence.java:85) ~[mybatis-plus-core-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.core.incrementer.DefaultIdentifierGenerator.<init>(DefaultIdentifierGenerator.java:39) ~[mybatis-plus-core-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.core.MybatisSqlSessionFactoryBuilder.build(MybatisSqlSessionFactoryBuilder.java:89) ~[mybatis-plus-core-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.buildSqlSessionFactory(MybatisSqlSessionFactoryBean.java:606) ~[mybatis-plus-extension-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.afterPropertiesSet(MybatisSqlSessionFactoryBean.java:431) ~[mybatis-plus-extension-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean.getObject(MybatisSqlSessionFactoryBean.java:628) ~[mybatis-plus-extension-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration.sqlSessionFactory(MybatisPlusAutoConfiguration.java:219) ~[mybatis-plus-boot-starter-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$e7c515fe.CGLIB$sqlSessionFactory$1(<generated>) ~[mybatis-plus-boot-starter-3.4.3.jar!/:3.4.3]
	at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$e7c515fe$$FastClassBySpringCGLIB$$5e99374b.invoke(<generated>) ~[mybatis-plus-boot-starter-3.4.3.jar!/:3.4.3]
	at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331) ~[spring-context-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
	at com.baomidou.mybatisplus.autoconfigure.MybatisPlusAutoConfiguration$$EnhancerBySpringCGLIB$$e7c515fe.sqlSessionFactory(<generated>) ~[mybatis-plus-boot-starter-3.4.3.jar!/:3.4.3]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_291]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_291]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_291]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_291]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
	... 66 common frames omitted

解决方式：

通过hostname发现本机为tzb.xyttt
修改hostname为localhost 命令： hostnamectl set-hostname localhost
参考地址