springboot+mybatis集成多數據源

1.首先是pom.xml中引用

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${alibaba.druid}</version>
        </dependency>

2.yml文件中的配置

jdbc:
  url: jdbc:mysql://localhost:3306/web?characterEncoding=UTF-8&zeroDateTimeBehavior=round&useSSL=false
  username: root
  password: accp
  driverClassName: com.mysql.jdbc.Driver
jdbc1:
  url: jdbc:mysql://localhost:3306/web1?characterEncoding=UTF-8&zeroDateTimeBehavior=round&useSSL=false
  username: root
  password: accp
  driverClassName: com.mysql.jdbc.Driver
jdbc2:
  url: jdbc:mysql://localhost:3306/accp?characterEncoding=UTF-8&zeroDateTimeBehavior=round&useSSL=false
  username: root
  password: accp
  driverClassName: com.mysql.jdbc.Driver

3.創建DatabaseContextHolder.java 類

package com.test.web.common.mybatis;

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();
    }

    public static void close(){
        contextHolder.remove();
    }
}

4.創建多數據源枚舉類DatabaseType.java

package com.test.web.common.mybatis;

/**
 * 數據源枚舉
 */
public enum DatabaseType {
    ONEDB,TWODB,TDB
}

5.創建DynamicDataSource.java 類

package com.test.web.common.mybatis;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {
    protected Object determineCurrentLookupKey() {
        return DatabaseContextHolder.getDatabaseType();
    }
}

6.創建MyBatisConfig.java 類

package com.test.web.common.mybatis;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

@Configuration // 該註解類似於spring配置文件
public class MyBatisConfig {
    @Autowired
    private Environment env;

    /**
     * 創建數據源(數據源的名稱：方法名可以取爲XXXDataSource(),XXX爲數據庫名稱,該名稱也就是數據源的名稱)
     */
    @Bean
    @Primary
    public DataSource DbDataSource() throws Exception {
        Properties props = new Properties();
        props.put("driverClassName", env.getProperty("jdbc.driverClassName"));
        props.put("url", env.getProperty("jdbc.url"));
        props.put("username", env.getProperty("jdbc.username"));
        props.put("password", env.getProperty("jdbc.password"));
        return DruidDataSourceFactory.createDataSource(props);
    }

    @Bean
    public DataSource Db2DataSource() throws Exception {
        Properties props = new Properties();
        props.put("driverClassName", env.getProperty("jdbc1.driverClassName"));
        props.put("url", env.getProperty("jdbc1.url"));
        props.put("username", env.getProperty("jdbc1.username"));
        props.put("password", env.getProperty("jdbc1.password"));
        return DruidDataSourceFactory.createDataSource(props);
    }

    @Bean
    public DataSource Db3DataSource() throws Exception {
        Properties props = new Properties();
        props.put("driverClassName", env.getProperty("jdbc2.driverClassName"));
        props.put("url", env.getProperty("jdbc2.url"));
        props.put("username", env.getProperty("jdbc2.username"));
        props.put("password", env.getProperty("jdbc2.password"));
        return DruidDataSourceFactory.createDataSource(props);
    }



    /**
     * @Qualifier 根據名稱進行注入，通常是在具有相同的多個類型的實例的一個注入（例如有多個DataSource類型的實例）
     */
    @Bean
    public DynamicDataSource dataSource(@Qualifier("DbDataSource") DataSource myTestDbDataSource,
                                        @Qualifier("Db2DataSource") DataSource myTestDb2DataSource,
                                        @Qualifier("Db3DataSource") DataSource myTestDb3DataSource) {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DatabaseType.ONEDB, myTestDbDataSource);
        targetDataSources.put(DatabaseType.TWODB, myTestDb2DataSource);
        targetDataSources.put(DatabaseType.TDB, myTestDb3DataSource);
        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSources);// 該方法是AbstractRoutingDataSource的方法
        dataSource.setDefaultTargetDataSource(myTestDbDataSource);// 默認的datasource設置爲myTestDbDataSource

        return dataSource;
    }

    /**
     * 根據數據源創建SqlSessionFactory
     */
    @Bean
    public SqlSessionFactory sqlSessionFactory(DynamicDataSource ds) throws Exception {
        SqlSessionFactoryBean fb = new SqlSessionFactoryBean();

        fb.setDataSource(ds);// 指定數據源(這個必須有，否則報錯)
        // 下邊兩句僅僅用於*.xml文件，如果整個持久層操作不需要使用到xml文件的話（只用註解就可以搞定），則不加
        fb.setTypeAliasesPackage(env.getProperty("mybatis.typeAliasesPackage"));// 指定基包
        fb.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources(env.getProperty("mybatis.mapper-locations")));//

        fb.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
        return fb.getObject();
    }


    /**
     * 配置事務管理器
     */
    @Bean
    public DataSourceTransactionManager transactionManager(DynamicDataSource dataSource) throws Exception {
        return new DataSourceTransactionManager(dataSource);
    }


}

7.在啓動類中加上

@SpringBootApplication(exclude = {
        MyBatisConfig.class
})

8.下面是在service中的使用

DatabaseContextHolder.close();
//切換數據源就使用枚舉類
DatabaseContextHolder.setDatabaseType(DatabaseType.ONEDB);