簡述

應公司需求，結合網上的許多資料和公司專案配置實現多資料來源。在此記錄一下配置過程，以供大家參考。

專案簡介

框架用的是SpringBoot+Mybatis，初始資料庫是MySQL，具體MySQL的整合在這裡不做詳細說明，要求是新增一個Oracle的資料來源，實現可以同時查詢MySQL和Oracle兩個資料庫的功能。專案所用資料來源是阿里的Druid，沒有用傳統的配置檔案，用的是disconf進行的配置管理。

配置資料庫

pom檔案就不寫了，比較簡單，Oracle的包新增下就可以了。主要是資料庫這邊的配置，我將MySQL和Oracle的資料庫配置寫在了一起。

package
 
 com.server.configs;
import com.alibaba.druid.filter.Filter;
import com.alibaba.druid.filter.stat.StatFilter;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.wall.WallConfig;
import com.alibaba.druid.wall.WallFilter;
import com.core.mapper.JdbcMapper;
import com.core.mapper.OracleJdbcMapper;
import
 
 org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import javax.sql.DataSource;
import
 
 java.util.ArrayList;
import java.util.List;

/**
 * Created by jht on 2017-5-25.
 */
@SuppressWarnings("ALL")
@Configuration
public class DatabaseConfig {

    @Autowired
    private JdbcMapper jdbcMapper;
    @Autowired
    private OracleJdbcMapper oracleJdbcMapper;

    @Primary
    @Bean(name = "mysqlDataSource")
    public DataSource dataSource() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setDriverClassName(jdbcMapper.getDriverClassName());
        datasource.setUrl(jdbcMapper.getUrl());
        datasource.setUsername(jdbcMapper.getUsername());
        datasource.setPassword(jdbcMapper.getPassword());
        datasource.setInitialSize(jdbcMapper.getInitialSize());
        datasource.setMaxActive(jdbcMapper.getMaxActive());
        datasource.setMaxWait(jdbcMapper.getMaxWait());
        datasource.setMinIdle(jdbcMapper.getMinIdle());
        datasource.setTimeBetweenEvictionRunsMillis(jdbcMapper.getTimeBetweenEvictionRunsMillis());
        datasource.setMinEvictableIdleTimeMillis(jdbcMapper.getMinEvictableIdleTimeMillis());
        datasource.setValidationQuery(jdbcMapper.getValidationQuery());
        datasource.setTestWhileIdle(jdbcMapper.getTestWhileIdle());
        datasource.setTestOnBorrow(jdbcMapper.getTestOnBorrow());
        datasource.setTestOnReturn(jdbcMapper.getTestOnReturn());
        datasource.setMaxOpenPreparedStatements(jdbcMapper.getMaxOpenPreparedStatements());
        datasource.setRemoveAbandoned(jdbcMapper.getRemoveAbandoned());
        datasource.setRemoveAbandonedTimeout(jdbcMapper.getRemoveAbandonedTimeout());
        datasource.setLogAbandoned(jdbcMapper.getLogAbandoned());
        List<Filter> list = new ArrayList();
        list.add(new StatFilter());
        WallFilter wallFilter = new WallFilter();
        WallConfig config = new WallConfig();
        config.setMultiStatementAllow(true);
        wallFilter.setConfig(config);
        list.add(wallFilter);
        datasource.setProxyFilters(list);

        return datasource;

    }

    @Bean(name = "oracleDataSource")
    public DataSource oracleDataSource() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setDriverClassName(oracleJdbcMapper.getDriverClassName());
        datasource.setUrl(oracleJdbcMapper.getUrl());
        datasource.setUsername(oracleJdbcMapper.getUsername());
        datasource.setPassword(oracleJdbcMapper.getPassword());
        datasource.setInitialSize(oracleJdbcMapper.getInitialSize());
        datasource.setMaxActive(oracleJdbcMapper.getMaxActive());
        datasource.setMaxWait(oracleJdbcMapper.getMaxWait());
        datasource.setMinIdle(oracleJdbcMapper.getMinIdle());
        datasource.setTimeBetweenEvictionRunsMillis(oracleJdbcMapper.getTimeBetweenEvictionRunsMillis());
        datasource.setMinEvictableIdleTimeMillis(oracleJdbcMapper.getMinEvictableIdleTimeMillis());
        datasource.setValidationQuery(oracleJdbcMapper.getValidationQuery());
        datasource.setTestWhileIdle(oracleJdbcMapper.getTestWhileIdle());
        datasource.setTestOnBorrow(oracleJdbcMapper.getTestOnBorrow());
        datasource.setTestOnReturn(oracleJdbcMapper.getTestOnReturn());
        datasource.setMaxOpenPreparedStatements(oracleJdbcMapper.getMaxOpenPreparedStatements());
        datasource.setRemoveAbandoned(oracleJdbcMapper.getRemoveAbandoned());
        datasource.setRemoveAbandonedTimeout(oracleJdbcMapper.getRemoveAbandonedTimeout());
        datasource.setLogAbandoned(oracleJdbcMapper.getLogAbandoned());
        List<Filter> list = new ArrayList();
        list.add(new StatFilter());
        WallFilter wallFilter = new WallFilter();
        WallConfig config = new WallConfig();
        config.setMultiStatementAllow(true);
        wallFilter.setConfig(config);
        list.add(wallFilter);
        datasource.setProxyFilters(list);

        return datasource;

    }

}

其中JdbcMapper和OracleJdbcMapper是disconf配置檔案對應的配置類。
@Primary 用來指定一個主資料來源，這裡是將MySQL的資料庫設為主資料來源。

配置資料來源

多新增一個Oracle庫，mapper包和xml包還有PO都跟MySQL的分開，所以寫了兩套mybatis配置資料來源的配置類。先貼上主資料庫MySQL的配置類。

package com.server.configs;

import com.github.pagehelper.PageHelper;
import java.util.Properties;
import javax.annotation.Resource;
import javax.sql.DataSource;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mapstruct.Mapper;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
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.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

/**
 * Created by jht on 2017/5/30.
 */
@Configuration
@EnableTransactionManagement
@MapperScan(basePackages = "com.server.dao.mapper", sqlSessionTemplateRef = "mysqlSessionTemplate")
public class MyBatisConfig {

    @Resource
    DataSource mysqlDataSource;

    @Primary
    @Bean(name = "mysqlSessionFactory")
    public SqlSessionFactory mysqlSessionFactory() throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(mysqlDataSource);
        sessionFactory.setTypeAliasesPackage("com.ydx.server.model.mysql");
        //分頁外掛
        PageHelper pageHelper = new PageHelper();
        Properties properties = new Properties();
        properties.setProperty("reasonable", "true");
        properties.setProperty("supportMethodsArguments", "true");
        properties.setProperty("returnPageInfo", "check");
        properties.setProperty("params", "count=countSql");
        pageHelper.setProperties(properties);

        //新增外掛
        sessionFactory.setPlugins(new Interceptor[]{pageHelper});

        //新增XML目錄
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            sessionFactory.setMapperLocations(resolver.getResources("classpath:mapper/**/*.xml"));
            return sessionFactory.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Primary
    @Bean(name = "mysqlSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("mysqlSessionFactory") SqlSessionFactory mysqlSessionFactory) {
        return new SqlSessionTemplate(mysqlSessionFactory);
    }

    @Primary
    @Bean(name = "mysqlTransactionManager")
    public PlatformTransactionManager mysqlTransactionManager() {
        return new DataSourceTransactionManager(mysqlDataSource);
    }

}

需要注意的是因為是主資料庫，所以需要加@Primary；
@Bean的名字要需要寫清楚；
@MapperScan的包名要寫對；

下面是Oracle的配置類，差別不大。

package com.server.configs;

import com.github.pagehelper.PageHelper;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.annotation.Resource;
import javax.sql.DataSource;
import java.util.Properties;

/**
 * Created by jht on 2017/5/30.
 */
@Configuration
@EnableTransactionManagement
@MapperScan(basePackages = "com.server.dao.oracle", sqlSessionTemplateRef = "oracleSessionTemplate")
public class OracleMyBatisConfig {

    @Resource
    DataSource oracleDataSource;

    @Bean(name = "oracleSessionFactory")
    public SqlSessionFactory mysqlSessionFactory() throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(oracleDataSource);
        sessionFactory.setTypeAliasesPackage("com.ydx.server.model.mysql");
        //分頁外掛
        PageHelper pageHelper = new PageHelper();
        Properties properties = new Properties();
        properties.setProperty("reasonable", "true");
        properties.setProperty("supportMethodsArguments", "true");
        properties.setProperty("returnPageInfo", "check");
        properties.setProperty("params", "count=countSql");
        pageHelper.setProperties(properties);

        //新增外掛
        sessionFactory.setPlugins(new Interceptor[]{pageHelper});

        //新增XML目錄
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            sessionFactory.setMapperLocations(resolver.getResources("classpath:oraclemapper/*.xml"));
            return sessionFactory.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Bean(name = "oracleSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("oracleSessionFactory") SqlSessionFactory oracleSessionFactory) {
        return new SqlSessionTemplate(oracleSessionFactory);
    }

    @Bean(name = "oracleTransactionManager")
    public PlatformTransactionManager oracleTransactionManager() {
        return new DataSourceTransactionManager(oracleDataSource);
    }

}

跟MySQL的配置差不多,到此為止，多資料來源配置就算完成啦。接下來的測試我就不貼了。

總結

其實還有一種方式是動態配置資料來源的，用到了AOP，有時間在研究吧。這個方式比較死板，維護起來比較麻煩，適合那種只是想找一個簡單的多資料來源支援的專案。最重要的其實就是一步步的注入，先建立DataSource，然後通過注入DataSource建立SessionFactory，再建立事務，最後包裝到SqlSessionTemplate中。其中DAO包，PO類，xml所在位置都需要準確指定。所有@Bean都需要按照命名指定正確。注意這幾點，配置起來就會簡單許多了。