1 项目背景
在日常开发中，开发有时候拿不到数据库，依赖组件的密码，例如由devops进行配置，甚至放到一些密码管理组件中。这样就会出现密码错误的情况。项目发布成功，那么依赖项例如Mysql, 访问别的系统的ak, sk真的准备好了吗？配置错误，他们启动会报错吗？直到提测被打回才发现连接依赖组件出现问题。
2 mysql启动依赖检查
2.1 配置错误的密码启动springboot
(1)配置错误的mysql密码
(2)启动springboot，观察日志
(3)发现异常日志并且springboot启动了
(4)访问健康检查Http端口
返回正常相应200
也就是说，项目启动了，并且不依赖mysql的api是可以正常处理的。依赖mysql的api访问报错。
java
2024-07-24 06:45:13.806 INFO 13712 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2024-07-24 06:45:13.898 WARN 13712 --- [ main] com.zaxxer.hikari.util.DriverDataSource : Registered driver with driverClassName=com.mysql.jdbc.Driver was not found, trying direct instantiation.
2024-07-24 06:45:16.100 ERROR 13712 --- [ main] com.zaxxer.hikari.pool.HikariPool : HikariPool-1 - Exception during pool initialization.
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
2024-07-24 06:45:18.164 INFO 13712 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 9099 (http) with context path ''
2024-07-24 06:45:18.566 INFO 13712 --- [ main] c.study.config.server.ServerApplication : Started ServerApplication in 14.224 seconds (JVM running for 15.546)2.2 优化
在项目启动过程中，查询mysql(例如缓存，或者专门写一个检测类)，若报错，抛出runtimeException，springboot会自动停止启动
java
@Slf4j
@Component
public class InitCheckUtils {
@Autowired
private TestMapper testMapper;
@PostConstruct
public void init() {
try {
Long cnt = testMapper.selectCount(null);
log.info("dbTableCnt:{}", cnt);
} catch (Exception e) {
log.error("projectInitMysqlConnectError", e);
throw new RuntimeException("projectInitMysqlConnectError");
}
}
}
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'initCheckUtils': Invocation of init method failed; nested exception is java.lang.RuntimeException: projectInitMysqlConnectError
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:160) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:440) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1796) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:955) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:929) ~[spring-context-5.3.31.jar:5.3.31]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:591) ~[spring-context-5.3.31.jar:5.3.31]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.18.jar:2.7.18]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) ~[spring-boot-2.7.18.jar:2.7.18]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409) ~[spring-boot-2.7.18.jar:2.7.18]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.18.jar:2.7.18]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) ~[spring-boot-2.7.18.jar:2.7.18]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289) ~[spring-boot-2.7.18.jar:2.7.18]
at com.study.config.server.ServerApplication.main(ServerApplication.java:13) ~[classes/:na]
Caused by: java.lang.RuntimeException: projectInitMysqlConnectError
at com.study.config.server.utils.InitCheckUtils.init(InitCheckUtils.java:24) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:389) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:333) ~[spring-beans-5.3.31.jar:5.3.31]
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:157) ~[spring-beans-5.3.31.jar:5.3.31]
... 18 common frames omitted3 总结
（1）项目启动过程中，若依赖项没有准备好，可能不会报错，项目正常启动，启动后接受请求，就会产生错误并且影响业务。
（2）对此，项目启动的时候做一些检查，保证访问依赖组件正常。
（3）若项目启动检测到依赖组件不正常，那么阻止程序启动