第八章springboot+mybatis+多数据源

1 #the first datasource
 2 jdbc.driverClassName = com.mysql.jdbc.Driver
 3 jdbc.url = jdbc:mysql://xxx:3306/mytestdb?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
 4 jdbc.username = root
 5 jdbc.password = 123
 6 
 7 #the second datasource
 8 jdbc2.driverClassName = com.mysql.jdbc.Driver
 9 jdbc2.url = jdbc:mysql://xxx:3306/mytestdb2?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
10 jdbc2.username = root
11 jdbc2.password = 123

package com.xxx.firstboot.common.datasource;

/**
 * 列出所有的数据源key（常用数据库名称来命名）
 * 注意：
 * 1）这里数据源与数据库是一对一的
 * 2）DatabaseType中的变量名称就是数据库的名称
 */
public enum DatabaseType {
    mytestdb,mytestdb2
}

package com.xxx.firstboot.common.datasource;

/**
 * 作用：
 * 1、保存一个线程安全的DatabaseType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();
    }
}

package com.xxx.firstboot.common.datasource;

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

/**
 * 动态数据源（需要继承AbstractRoutingDataSource）
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    protected Object determineCurrentLookupKey() {
        return DatabaseContextHolder.getDatabaseType();
    }
}

package com.xxx.firstboot.common;

import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
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 com.alibaba.druid.pool.DruidDataSourceFactory;
import com.xxx.firstboot.common.datasource.DatabaseType;
import com.xxx.firstboot.common.datasource.DynamicDataSource;

/**
 * springboot集成mybatis的基本入口 1）创建数据源(如果采用的是默认的tomcat-jdbc数据源，则不需要)
 * 2）创建SqlSessionFactory 3）配置事务管理器，除非需要使用事务，否则不用配置
 */
@Configuration // 该注解类似于spring配置文件
@MapperScan(basePackages = "com.xxx.firstboot.mapper")
public class MyBatisConfig {

    @Autowired
    private Environment env;

    /**
     * 创建数据源(数据源的名称：方法名可以取为XXXDataSource(),XXX为数据库名称,该名称也就是数据源的名称)
     */
    @Bean
    public DataSource myTestDbDataSource() 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 myTestDb2DataSource() 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);
    }

    /**
     * @Primary 该注解表示在同一个接口有多个实现类可以注入的时候，默认选择哪一个，而不是让@autowire注解报错
     * @Qualifier 根据名称进行注入，通常是在具有相同的多个类型的实例的一个注入（例如有多个DataSource类型的实例）
     */
    @Bean
    @Primary
    public DynamicDataSource dataSource(@Qualifier("myTestDbDataSource") DataSource myTestDbDataSource,
            @Qualifier("myTestDb2DataSource") DataSource myTestDb2DataSource) {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DatabaseType.mytestdb, myTestDbDataSource);
        targetDataSources.put(DatabaseType.mytestdb2, myTestDb2DataSource);

        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSources);// 该方法是AbstractRoutingDataSource的方法
        dataSource.setDefaultTargetDataSource(myTestDbDataSource);// 默认的datasource设置为myTestDbDataSource

        return dataSource;
    }

    /**
     * 根据数据源创建SqlSessionFactory
     */
    @Bean
    public SqlSessionFactory sqlSessionFactory(DynamicDataSource ds) throws Exception {
        SqlSessionFactoryBean fb = new SqlSessionFactoryBean();
        fb.setDataSource(ds);// 指定数据源(这个必须有，否则报错)
        // 下边两句仅仅用于*.xml文件，如果整个持久层操作不需要使用到xml文件的话（只用注解就可以搞定），则不加
        fb.setTypeAliasesPackage(env.getProperty("mybatis.typeAliasesPackage"));// 指定基包
        fb.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources(env.getProperty("mybatis.mapperLocations")));//

        return fb.getObject();
    }

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

}

package com.xxx.firstboot.mapper;

import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;

import com.xxx.firstboot.domain.Shop;

public interface ShopMapper {

    @Select("SELECT * FROM t_shop WHERE id = #{id}")
    @Results(value = { @Result(id = true, column = "id", property = "id"),
                       @Result(column = "shop_name", property = "shopName") })
    public Shop getShop(@Param("id") int id);

}

package com.xxx.firstboot.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.xxx.firstboot.common.datasource.DatabaseContextHolder;
import com.xxx.firstboot.common.datasource.DatabaseType;
import com.xxx.firstboot.domain.Shop;
import com.xxx.firstboot.mapper.ShopMapper;

@Repository
public class ShopDao {
    @Autowired
    private ShopMapper mapper;

    /**
     * 获取shop
     */
    public Shop getShop(int id) {
        DatabaseContextHolder.setDatabaseType(DatabaseType.mytestdb2);
        return mapper.getShop(id);
    }
}

package com.xxx.firstboot.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.xxx.firstboot.dao.ShopDao;
import com.xxx.firstboot.domain.Shop;

@Service
public class ShopService {

    @Autowired
    private ShopDao dao;

    public Shop getShop(int id) {
        return dao.getShop(id);
    }
}

package com.xxx.firstboot.web;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.xxx.firstboot.domain.Shop;
import com.xxx.firstboot.service.ShopService;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;

@RestController
@RequestMapping("/shop")
@Api("shopController相关api")
public class ShopController {

    @Autowired
    private ShopService service;

    @ApiOperation("获取shop信息,测试多数据源")
    @RequestMapping(value = "/getShop", method = RequestMethod.GET)
    public Shop getShop(@RequestParam("id") int id) {
        return service.getShop(id);
    }

}