一、异常信息

今天早上启动项目，突然出现了如下异常，百度了一下没有合适的解决方案，决定从源码入手，看看能不能解决。

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'flywayInitializer' defined in class path resource [org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration$FlywayConfiguration.class]: Invocation of init method failed; nested exception is org.flywaydb.core.api.exception.FlywayValidateException: Validate failed: Migrations have failed validation
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:917) ~[spring-context-5.3.4.jar:5.3.4]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:582) ~[spring-context-5.3.4.jar:5.3.4]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:144) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:767) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:426) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:326) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1311) ~[spring-boot-2.4.3.jar:2.4.3]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) ~[spring-boot-2.4.3.jar:2.4.3]
	at com.zhx.realpro.CloudAlarmApplication.main(CloudAlarmApplication.java:33) ~[classes/:na]
Caused by: org.flywaydb.core.api.exception.FlywayValidateException: Validate failed: Migrations have failed validation
	at org.flywaydb.core.Flyway$1.execute(Flyway.java:172) ~[flyway-core-7.1.1.jar:na]
	at org.flywaydb.core.Flyway$1.execute(Flyway.java:164) ~[flyway-core-7.1.1.jar:na]
	at org.flywaydb.core.Flyway.execute(Flyway.java:538) ~[flyway-core-7.1.1.jar:na]
	at org.flywaydb.core.Flyway.migrate(Flyway.java:164) ~[flyway-core-7.1.1.jar:na]
	at org.springframework.boot.autoconfigure.flyway.FlywayMigrationInitializer.afterPropertiesSet(FlywayMigrationInitializer.java:66) ~[spring-boot-autoconfigure-2.4.3.jar:2.4.3]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845) ~[spring-beans-5.3.4.jar:5.3.4]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782) ~[spring-beans-5.3.4.jar:5.3.4]
	... 19 common frames omitted

二、异常分析

根据错误信息，报的是FlywayValidateException异常，找到这个类打上断点
启动项目，查看调用链

找到了抛出异常的位置，在它前面的这行打上断点启动项目，因为是这个结果判断之后才抛出异常
ValidateResult validateResult = doValidate(database, migrationResolver, schemaHistory, schemas, callbackExecutor, true);
跟进这行去看

ValidateResult validateResult = new DbValidate(database, schemaHistory, schemas, migrationResolver, configuration, ignorePending, callbackExecutor).validate();

validate方法里面，在Callable的call方法做校验，这块感觉有点过度设计了，没找到另起线程的好处。

migrationInfoService的refresh方法sql文件加载进来了，这块就不看了。接着往下进入List<ValidateOutput> invalidMigrations = migrationInfoService.validate();

验证所有sql文件的checksum，如果sql文件是第一次执行，会产生一个checksum。之后改了sql文件的内容checksum的值就会发生改变，从而验证失败validateError就不会为空，那么invalidMigrations就会添加一条。进入migrationInfo.validate();

走到这块发现两个checksum不一致。跟进去resolvedMigration.checksumMatches

不一致就返回false

返回一个ErrorDetails，错误信息很详细，不过最终却没有输出，看看怎么回事，返回到DbValidate.DbValidate方法，call执行之后返回了result。

目前为止result里面还是有详细的错误信息的

校验失败的sql文件不为空就进入 validationError = new ErrorDetails(ErrorCode.VALIDATE_ERROR, "Migrations have failed validation");，这里的异常信息写死成“Migrations have failed validation”，导致更加详细的错误信息没有输出，记得老版本的flyway是有输出的。这样改了反而不直观。返回到Flyway.migrate

校验失败，抛出异常信息“ Migrations have failed validation”。

三、解决方案

前面已经讲到一般是由于sql文件在第一次执行之后发生了改变导致的。

• 方案一：不要改动sql文件，增加新的sql文件去修改表
• 方案二：直接将数据库表flyway_schema_history中的checksum改成新生成的checksum，但是不建议直接改库。估计也是这个原因，新版的flyway就不把新产生的checksum打印出来了