liquibase 数据库重构工具

1. Liquibase简介

Liquibase是一个用于跟踪、管理和应用数据库变化的开源的数据库重构工具。它将所有数据库的变化（包括数据库结构和数据）都保存在changelog文件中，便于版本控制，它的目标是提供一种数据库类型无关的数据库类型无关的解决方案，通过执行schema类型的文件来达到迁移。

-> 官方文档

Liquibase特性

• 支持几乎所有主流的数据库，如Mysql、PostgreSql、Oracle、SQL server、DB2等。

• 支持多发开者的协作维护

• 日志文件支持多种格式，如xml、yaml、JSON、SQL等

• 支持上下文相关逻辑

• 生成数据库变更文档

• 支持多种运行方式，如命令行、spring集成、maven插件、Gradle插件等

代码工程

简单案例

实验mysql数据初始化

1. 引入pom

   <?xml version="1.0" encoding="UTF-8"?>
   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
       <modelVersion>4.0.0</modelVersion>
   
       <groupId>org.example</groupId>
       <artifactId>liquibase</artifactId>
       <version>1.0-SNAPSHOT</version>
   
       <name>liquibase</name>
       <!-- FIXME change it to the project's website -->
       <url>http://www.example.com</url>
   
       <properties>
           <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
           <maven.compiler.release>17</maven.compiler.release>
       </properties>
       <parent>
           <artifactId>spring-boot-starter-parent</artifactId>
           <groupId>org.springframework.boot</groupId>
           <version>2.4.5</version>
       </parent>
   
       <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
           </dependency>
   
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-test</artifactId>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-autoconfigure</artifactId>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-jdbc</artifactId>
           </dependency>
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
           </dependency>
           <dependency>
               <groupId>org.liquibase</groupId>
               <artifactId>liquibase-core</artifactId>
           </dependency>
       </dependencies>
   
       <build>
           <plugins>
               <plugin>
                   <groupId>org.liquibase</groupId>
                   <artifactId>liquibase-maven-plugin</artifactId>
                   <version>4.29.1</version>
                   <configuration>
                       <!--生成Changelog的输出目录-->
                       <outputChangeLogFile>${basedir}/src/main/resources/liquibase/generate/changeLog.xml
                       </outputChangeLogFile>
                       <!--DB连接信息-->
                       <driver>com.mysql.jdbc.Driver</driver>
                       <url>jdbc:mysql://localhost:3306/demo?useSSL=false</url>
                       <username>root</username>
                       <password>xiaoyuge</password>
                       <dropFirst>false</dropFirst>
                       <verbose>true</verbose>
                       <logging>debug</logging>
                       <promptOnNonLocalDatabase>false</promptOnNonLocalDatabase>
                       <outputFileEncoding>UTF-8</outputFileEncoding>
                       <propertyFileWillOverride>true</propertyFileWillOverride>
                   </configuration>
               </plugin>
           </plugins>
       </build>
   </project>

2. 创建数据库表

   CREATE TABLE `user_info` (
     `id` int NOT NULL AUTO_INCREMENT,
     `name` varchar(50) default null,
     PRIMARY KEY (`id`)
   ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

3. changelog配置目录
   
   运行后会在resource/liquibase/generate下面生成changeLog.xml文件
   

4. 创建master.xml，包含需要的changelog目录

   <?xml version="1.0" encoding="utf-8"?>
   <databaseChangeLog
           xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
       http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.5.xsd">
   
       <include file="liquibase/generate/changeLog.xml" />
   
   </databaseChangeLog>

5. yml配置文件

   spring:
      datasource:
         url: jdbc:mysql://127.0.0.1:3306/demo?createDatabaseIfNotExist=true&allowMultiQueries=true&useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
         username: root
         password: xiaoyuge
         driver-class-name: com.mysql.cj.jdbc.Driver
   
      liquibase:
         change-log: change-log: classpath:liquibase/master.xml
         contexts: dev
         enabled: true
         #用于跟踪并发Liquibase使用情况的表的名称
         database-change-log-lock-table: DATABASECHANGELOGLOCK
         #用于跟踪更改历史记录的表的名称
         database-change-log-table: DATABASECHANGELOG

6. 启动程序，等待1分钟后，数据库会创建两张记录表

   Liquibase默认会生成databasechangelog和databasechangeloglock表（记录变更日志）

   

多数据源模式

每个数据源配置都独立配置一套资源文件

1. yml配置

   spring:
      datasource:
         url: jdbc:mysql://127.0.0.1:3306/demo?createDatabaseIfNotExist=true&allowMultiQueries=true&useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
         username: root
         password: xiaoyuge
         driver-class-name: com.mysql.cj.jdbc.Driver
         liquibase:
           change-log: classpath:liquibase/datasource1/master.xml
       datasource2:
         username: root
         password: 123456
         jdbc-url: jdbc:mysql://localhost:3306/web
         driver-class-name: com.mysql.jdbc.Driver
         liquibase:
           change-log: classpath:liquibase/datasource2/master.xml

2. 注册Bean

   @Configuration
   public class LiquibaseConfiguration {
   
   
       /**
        * datasource1
        */
       @Bean
       public SpringLiquibase datasource1Liquibase() {
           // 获取对应数据源
           DataSource dataSource;
           SpringLiquibase liquibase = new SpringLiquibase();
           // Liquibase文件路径
           liquibase.setChangeLog("classpath:liquibase/datasource1/master.xml");
           liquibase.setDataSource(dataSource);
           liquibase.setShouldRun(true);
           liquibase.setResourceLoader(new DefaultResourceLoader());
           // 覆盖Liquibase changelog表名
           liquibase.setDatabaseChangeLogTable("datasource1_changelog_table");
           liquibase.setDatabaseChangeLogLockTable("datasource1_changelog_lock_table");
           return liquibase;
       }
   
       /**
        * datasource2
        */
       @Bean
       public SpringLiquibase datasource2Liquibase() {
           // 获取对应数据源
           DataSource dataSource;
           SpringLiquibase liquibase = new SpringLiquibase();
           liquibase.setChangeLog("classpath:classpath:liquibase/datasource2/master.xml");
           liquibase.setDataSource(dataSource);
           liquibase.setShouldRun(true);
           liquibase.setResourceLoader(new DefaultResourceLoader());
           liquibase.setDatabaseChangeLogTable("datasource2_changelog_table");
           liquibase.setDatabaseChangeLogLockTable("datasource2_changelog_lock_table");
           return liquibase;
       }
   }