对于数据迁移的概念，相信大家已经都比较熟悉。那么，什么是数据迁移？为什么需要数据迁移？在这里就不再做相关分享啦~。接下来主要分享一下数据迁移工具 Flyway 使用。

Flyway is the Apache v2 licensed open-source tool that makes database migrations easy. It strongly favors simplicity and convention over configuration.

Flyway 是一款开源的数据库迁移工具，它认为简单和约定优于配置。没有繁琐的配置，有 6 个主要基本命令：Migrate, Clean, Info, Validate, Baseline 和 Repair。

Flyway received the highest distinction on the Thoughtworks Technology Radar by being placed in the adopt category.

如何使用 Flyway？

Flyway支持很多种和应用集成的方法，这里主要分享一下Gradle集成Flyway的使用。

Setup Repo db-migration-flyway：

$ gradle init --type java-libray

Add Gradle Flyway plugin

• Change build.gradle file content

buildscript {repositories {maven { url "https://plugins.gradle.org/m2/" }}dependencies {classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"}
}apply plugin: "idea"
apply plugin: 'java'
apply plugin: "org.flywaydb.flyway"

• Build repo

$ ./gradlew build

Config Flyway

• Change [build.gradle] file content

buildscript {repositories {maven { url "https://plugins.gradle.org/m2/" }}dependencies {classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"}
}apply plugin: "idea"
apply plugin: 'java'
apply plugin: "org.flywaydb.flyway"flyway {driver = 'com.mysql.jdbc.Driver'url = "jdbc:mysql://127.0.0.1:3306/flyway_dev"user = 'mysql'password = 'mysql'table = 'flyway_dev_schema_version'locations = ["filesystem:${projectDir}/src/main/resources/db/migration/mysql"]sqlMigrationPrefix = 'MySQL-'
}repositories {jcenter()
}dependencies {compile 'mysql:mysql-connector-java:5.1.34'
}

• Build repo

$ ./gradlew build

Add Migration Scripts

• Create file MySQL-1_1__create_users_table.sql

CREATE TABLE USERS (ID         BIGINT PRIMARY KEY    AUTO_INCREMENT,USERNAME   VARCHAR(32)  NOT NULL UNIQUE,CREATED_AT TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3)
);

• Create Mysql Database flyway_dev with user mysql and password mysql

• Migration

$ ./gradlew flywayMigrate -i

配置管理

对于DEV、QA、TEST、STAGE、PROD针对不同的环境，需要会使用不一样的数据库配置。

• 在工程目录下创建文件config/dev/db.properties, config/test/db.properties, config/prod/db.properties:

// config/dev/db.properties
db.url=jdbc:mysql://127.0.0.1:3306/flyway_dev
db.user=mysql
db.password=mysql// config/test/db.properties
db.url=jdbc:mysql://127.0.0.1:3306/flyway_test
db.user=mysql
db.password=mysql// config/prod/db.properties
db.url=jdbc:mysql://127.0.0.1:3306/flyway_prod
db.user=mysql
db.password=mysql

• 修改 build.gradle 文件

buildscript {repositories {maven { url "https://plugins.gradle.org/m2/" }}dependencies {classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"}
}apply plugin: "idea"
apply plugin: 'java'
apply plugin: "org.flywaydb.flyway"def properties = new Properties()
properties.load(project.file("config/${env}/db.properties").newReader())flyway {driver = 'com.mysql.jdbc.Driver'url = properties.get('db.url')user = properties.get('db.user')password = properties.get('db.password')table = 'flyway_dev_schema_version'locations = ["filesystem:${projectDir}/src/main/resources/db/migration/mysql"]sqlMigrationPrefix = 'MySQL-'
}repositories {jcenter()
}dependencies {compile 'mysql:mysql-connector-java:5.1.34'
}

• Create Mysql Database flyway_test with user mysql and password mysql

• Migration test env

$ ./gradlew -Penv=test flywayMigrate -i

写在最后

这里只是简单的分享了一下，Gradle 和 Flyway 的集成。Flyway 还有很多功能值得去探索...

原文链接