Flyway是一个版本控制应用程序，可以在所有实例中轻松可靠地演变数据库模式。

许多软件项目使用关系数据库。 这需要处理数据库迁移，通常也称为模式迁移。

在本章中，将详细了解如何在Spring Boot应用程序中配置Flyway数据库。

配置Flyway数据库

首先，从Spring Initializer 页面 www.start.spring.io[2] 下载Spring Boot项目并选择以下依赖项 –

1.Spring Boot Starter Web2.Flyway3.MySQL4.JDBC

Maven用户可以在pom.xml 文件中添加以下依赖项。

<dependency>
   <groupId>org.flywaydb</groupId>
   <artifactId>flyway-core</artifactId>
</dependency>


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


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


<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
</dependency>


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

在应用程序属性中，需要配置数据库属性以创建DataSource，还要在应用程序属性中配置的flyway属性。

对于属性文件用户，请在application.properties 文件中添加以下属性。

spring.application.name = flywayapp  


spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/USERSERVICE?autoreconnect=true
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.testOnBorrow = true
spring.datasource.testWhileIdle = true
spring.datasource.timeBetweenEvictionRunsMillis = 60000
spring.datasource.minEvictableIdleTimeMillis = 30000
spring.datasource.validationQuery = SELECT 1
spring.datasource.max-active = 15
spring.datasource.max-idle = 10
spring.datasource.max-wait = 8000


flyway.url = jdbc:mysql://localhost:3306/mysql
flyway.schemas = USERSERVICE
flyway.user = root
flyway.password = root

现在，在src/main/resources/db/migration 目录下创建一个SQL文件。 将SQL文件命名为V1__Initial.sql

CREATE TABLE USERS (ID INT AUTO_INCREMENT PRIMARY KEY, USERID VARCHAR(45));
INSERT INTO USERS (ID, USERID) VALUES (1, 'yiibai.com');

主 Spring Boot应用程序类文件代码如下 –

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@SpringBootApplication
public class FlywayappApplication {
   public static void main(String[] args) {
      SpringApplication.run(FlywayappApplication.class, args);
   }
}

使用以下命令运行JAR文件 –

java –jar <JARFILE>

现在，Tomcat在端口8080上启动，在控制台窗口中，可以看到如此处所示的flyway数据库日志。

pringframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-08 21:07:58.525  INFO 16088 --- [           main] o.f.core.internal.util.VersionPrinter    : Flyway 3.2.1 by Boxfuse
Mon Oct 08 21:07:58 CST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Mon Oct 08 21:07:58 CST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
2018-10-08 21:07:58.825  INFO 16088 --- [           main] o.f.c.i.dbsupport.DbSupportFactory       : Database: jdbc:mysql://localhost:3306/mysql (MySQL 5.7)
2018-10-08 21:07:58.860  INFO 16088 --- [           main] o.f.core.internal.command.DbValidate     : Validated 1 migration (execution time 00:00.014s)
2018-10-08 21:07:59.150  INFO 16088 --- [           main] o.f.c.i.metadatatable.MetaDataTableImpl  : Creating Metadata table: `testdb`.`schema_version`
2018-10-08 21:07:59.987  INFO 16088 --- [           main] o.f.core.internal.command.DbMigrate      : Current version of schema `testdb`: << Empty Schema >>
2018-10-08 21:07:59.988  INFO 16088 --- [           main] o.f.core.internal.command.DbMigrate      : Migrating schema `testdb` to version 1 - Initial
2018-10-08 21:08:00.092  INFO 16088 --- [           main] o.f.core.internal.command.DbMigrate      : Successfully applied 1 migration to schema `testdb` (execution time 00:00.947s).
2018-10-08 21:08:00.339  INFO 16088 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-10-08 21:08:00.515  INFO 16088 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2018-10-08 21:08:00.526  INFO 16088 --- [           main] c.yiibai.flywayapp.FlywayappApplication  : Started FlywayappApplication in 6.384 seconds (JVM running for 6.903)
2018-10-08 21:08:20.802  INFO 16088 --- [       Thread-3] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@14514713: startup date [Mon Oct 08 21:07:54 CST 2018]; root of context hierarchy
2018-10-08 21:08:20.810  INFO 16088 --- [       Thread-3] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown

现在连接到数据库并执行选择查询。结果如下所示 –