SpringBoot+Mybatis 實現動態數據源切換方案

背景

最近讓我做一個大數據的系統，分析了一下，麻煩的地方就是多數據源切換抽取數據。考慮到可以跨服務器跨數據庫抽數，再整理數據，就配置了這個動態數據源的解決方案。在此分享給大家。

實現方案

數據庫配置文件

我們項目使用的是yml形式的配置文件，采用的是hikari的數據庫連接池。第一步我們自然是配置多個數據庫源頭。
我們找到spring的datasource，在下方配置三個數據源。

spring:
  application:
    name: dynamicDatasource
  datasource:
    test1:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test1?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    test2:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test2?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    test3:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test3?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    hikari:
      leak-detection-threshold: 2000

定義數據源實體類

我們可以建立個datasourceBean文件夾專門管理數據源的實體類。
我們這里要建立三個實體類。分別對應test1，test2，test3

@Configuration
public class Test1DataSourceBean {

    @Value("${spring.datasource.test1.driver-class-name}")
    private String test1Driver;

    @Value("${spring.datasource.test1.url}")
    private String test1Url;

    @Value("${spring.datasource.test1.username}")
    private String test1Username;

    @Value("${spring.datasource.test1.password}")
    private String test1Password;

    @Bean(name="test1DataSource")
    public DataSource test1DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test1Driver);
        dataSource.setJdbcUrl(test1Url);
        dataSource.setUsername(test1Username);
        dataSource.setPassword(test1Password);
        return dataSource;
    }
}

@Configuration
public class Test2DataSourceBean {

    @Value("${spring.datasource.test2.driver-class-name}")
    private String test2Driver;

    @Value("${spring.datasource.test2.url}")
    private String test2Url;

    @Value("${spring.datasource.test2.username}")
    private String test2Username;

    @Value("${spring.datasource.test2.password}")
    private String test2Password;

    @Bean(name="test2DataSource")
    public DataSource test2DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test2Driver);
        dataSource.setJdbcUrl(test2Url);
        dataSource.setUsername(test2Username);
        dataSource.setPassword(test2Password);
        return dataSource;
    }
}

@Configuration
public class Test3DataSourceBean {

    @Value("${spring.datasource.test3.driver-class-name}")
    private String test3Driver;

    @Value("${spring.datasource.test3.url}")
    private String test3Url;

    @Value("${spring.datasource.test3.username}")
    private String test3Username;

    @Value("${spring.datasource.test3.password}")
    private String test3Password;

    @Bean(name="test3DataSource")
    public DataSource test3DataSource() throws Exception{
        HikariDataSource dataSource = new HikariDataSource();
        dataSource.setDriverClassName(test3Driver);
        dataSource.setJdbcUrl(test3Url);
        dataSource.setUsername(test3Username);
        dataSource.setPassword(test3Password);
        return dataSource;
    }
}

定義一個枚舉類管理數據源

public enum DatabaseType {

    test1("test1", "test1"),
    test2("test2", "test2"),
    test3("test3","test3");

    private String name;
    private String value;

    DatabaseType(String name, String value){
        this.name = name;
        this.value = value;
    }

    public String getName(){
        return name;
    }

    public String getValue(){
        return value;
    }
}

定義一個線程安全的數據源容器

public class DatabaseContextHolder {

    private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>();

    public static void setDatabaseType(DatabaseType type){
        contextHolder.set(type);
    }

    public static DatabaseType getDatabaseType(){
        return contextHolder.get();
    }
}

定義動態數據源

public class DynamicDataSource extends AbstractRoutingDataSource{

    protected Object determineCurrentLookupKey() {
        return DatabaseContextHolder.getDatabaseType();
    }
}

mybatis配置類

網上的很多文章配置出來都會產生數據源循環依賴的問題，這里解決了這個問題。

@Configuration
@MapperScan(basePackages="cn.test.jichi", sqlSessionFactoryRef="sessionFactory")
public class MybatisConfig {

    /**
     *  @Description:設置動態數據源
     */
    @Bean(name="dynamicDataSource")
    @Primary
    public DynamicDataSource DataSource(
            @Qualifier("test1DataSource") DataSource test1DataSource,
            @Qualifier("test2DataSource") DataSource test2DataSource,
            @Qualifier("test3DataSource") DataSource test3DataSource){
        Map<Object, Object> targetDataSource = new HashMap<>();
        targetDataSource.put(DatabaseType.test1, test1DataSource);
        targetDataSource.put(DatabaseType.test2, test2DataSource);
        targetDataSource.put(DatabaseType.test3, test3DataSource);
        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSource);
        dataSource.setDefaultTargetDataSource(test1DataSource);
        return dataSource;
    }

    /**
     *  @Description:根據動態數據源創建sessionFactory
     */
    @Bean(name="sessionFactory")
    public SqlSessionFactory sessionFactory(
            @Qualifier("test1DataSource") DataSource test1DataSource,
            @Qualifier("test2DataSource") DataSource test2DataSource,
            @Qualifier("test3DataSource") DataSource test3DataSource) throws Exception{
        SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        //構造方法，解決動態數據源循環依賴問題。
        sessionFactoryBean.setDataSource(this.DataSource(test1DataSource,test2DataSource, test3DataSource));
        return sessionFactoryBean.getObject();
    }
}

提供一個示例

    public void testDymnaicDatasource(){
        //不切換數據源默認是自己的。
        System.out.println("-----默認數據源");
        DemoEntity totalCount = demoMapper.getTotalCount();
        String nameCount1 = totalCount.getNameCount();
        String ageCount2 = totalCount.getAgeCount();
        System.out.println("nameCount:"+nameCount1);
        System.out.println("ageCount:"+ageCount2);
        //數據源切換為branch
        System.out.println("-----數據源為test2");
        DynamicDataSourceUtils.chooseBranchDataSource();
        Integer nameCount = demoMapper.getNameCount();
        Integer ageCount = demoMapper.getAgeCount();
        System.out.println("nameCount:"+nameCount);
        System.out.println("ageCount:"+ageCount);
        //數據源為basic
        System.out.println("-----數據源為test3");
        DynamicDataSourceUtils.chooseBasicDataSource();
        Integer ageCount1 = demoMapper.getAgeCount();
        System.out.println("ageCount:"+ageCount1);

    }

總結

至此實現了多數據源的動態切換。可以在同一個方法里面進行操作多個數據源。