spring 集成mybatis——多数据源切换

参考《spring 集成mybatis》，并进行修改。

一、新建一个数据库kad，然后新建用户表s_user

CREATE TABLE s_user(
user_id INT AUTO_INCREMENT PRIMARY KEY,
user_name VARCHAR(30),
user_birthday DATE,
user_salary DOUBLE
);
INSERT INTO `s_user` (`user_id`, `user_name`, `user_birthday`, `user_salary`) VALUES('2','marry','2015-04-18','300');

二、新建java项目

项目目录如下：

三、动态选择数据源

public class DataSourceContextHolder {  
	 
    private static final ThreadLocal contextHolder = new ThreadLocal();  
  
    public static void setDbType(String dbType) {  
        contextHolder.set(dbType);  
    }  
  
    public static String getDbType() {  
        return ((String) contextHolder.get());  
    }  
  
    public static void clearDbType() {  
        contextHolder.remove();  
    }  
}  

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

public class DynamicDataSource extends AbstractRoutingDataSource {  
    @Override  
    protected Object determineCurrentLookupKey() {  
        return DataSourceContextHolder.getDbType();  
    }  
}

四、beans.xml

这里用DynamicDataSource管理两个数据源ds1和ds2，后面我们可以在程序中动态选用其中一个数据源。

五、测试类

import static org.junit.Assert.assertEquals;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.domain.User;
import com.mapper.UserMapper;
import com.utils.DataSourceContextHolder;

@RunWith(SpringJUnit4ClassRunner.class)
// 使用Springtest框架
@ContextConfiguration("/beans.xml")
// 加载配置
public class MybatisSpringTest {
	@Autowired
	// 注入
	private UserMapper userMapper;

	@Test
	public void findByIdDs1() {
		DataSourceContextHolder.setDbType("ds1");     //注意这里在调用userMapper前切换到ds1的数据源

		User user = userMapper.findById(2);
		System.out.println(user);
		assertEquals("marry", user.getName());
	}

	@Test
	public void findByIdDs2() {
		DataSourceContextHolder.setDbType("ds2");     //注意这里在调用userMapper前切换到ds2的数据源

		User user = userMapper.findById(1);
		System.out.println(user);
		assertEquals("marry", user.getName());
	}
}

执行日志如下：

2015-05-09 18:34:42,859 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2015-05-09 18:34:42,875 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e87512] was not registered for synchronization because synchronization is not active
2015-05-09 18:34:42,953 [main] DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource
2015-05-09 18:34:42,953 [main] DEBUG [org.springframework.jdbc.datasource.DriverManagerDataSource] - Creating new JDBC DriverManager Connection to [jdbc:mysql://localhost:3306/kad]
2015-05-09 18:34:42,968 [main] DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.mysql.jdbc.JDBC4Connection@1dd40f3] will not be managed by Spring
2015-05-09 18:34:42,984 [main] DEBUG [com.mapper.UserMapper.findById] - ooo Using Connection [com.mysql.jdbc.JDBC4Connection@1dd40f3]
2015-05-09 18:34:42,984 [main] DEBUG [com.mapper.UserMapper.findById] - ==>  Preparing: select * from s_user where user_id = ? 
2015-05-09 18:34:43,109 [main] DEBUG [com.mapper.UserMapper.findById] - ==> Parameters: 2(Integer)
2015-05-09 18:34:43,156 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1e87512]
2015-05-09 18:34:43,156 [main] DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Returning JDBC Connection to DataSource
User [id=2, name=marry, birthday=Sat Apr 18 00:00:00 CST 2015, salary=300.0]

2015-05-09 18:34:43,171 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - Creating a new SqlSession
2015-05-09 18:34:43,171 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1245e75] was not registered for synchronization because synchronization is not active
2015-05-09 18:34:43,171 [main] DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Fetching JDBC Connection from DataSource
2015-05-09 18:34:43,171 [main] DEBUG [org.springframework.jdbc.datasource.DriverManagerDataSource] - Creating new JDBC DriverManager Connection to [jdbc:mysql://localhost:3306/mybatis]
2015-05-09 18:34:43,187 [main] DEBUG [org.mybatis.spring.transaction.SpringManagedTransaction] - JDBC Connection [com.mysql.jdbc.JDBC4Connection@13c2ac3] will not be managed by Spring
2015-05-09 18:34:43,187 [main] DEBUG [com.mapper.UserMapper.findById] - ooo Using Connection [com.mysql.jdbc.JDBC4Connection@13c2ac3]
2015-05-09 18:34:43,187 [main] DEBUG [com.mapper.UserMapper.findById] - ==>  Preparing: select * from s_user where user_id = ? 
2015-05-09 18:34:43,187 [main] DEBUG [com.mapper.UserMapper.findById] - ==> Parameters: 1(Integer)
2015-05-09 18:34:43,187 [main] DEBUG [org.mybatis.spring.SqlSessionUtils] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1245e75]
2015-05-09 18:34:43,187 [main] DEBUG [org.springframework.jdbc.datasource.DataSourceUtils] - Returning JDBC Connection to DataSource
User [id=1, name=marry, birthday=Sat Apr 18 00:00:00 CST 2015, salary=2000.0]

这样，我们可以看到在程序里可以切换不同的数据源。