summercool-ddl

Automatically exported from code.google.com/p/summercool-ddl

1.依赖 Xml代码收藏代码
org.summercool
summercool-ddl
1.0

源码svn地址：http://summercool-ddl.googlecode.com/svn/trunk 2.准备Sql映射文件 Xml代码收藏代码

insert into $[user]$( id, name ) values ( #{id}, #{name} ) 注意此处，对于需要分表或分库的表，使用“$[table name]$”这种方式表示。 3.Spring配置 Xml代码收藏代码 ${demo.datasource.master.jdbcUrl}

<bean id="dataSourceSlave" class="com.jolbox.bonecp.BoneCPDataSource"  
    destroy-method="close">  
    <property name="driverClass" value="com.mysql.jdbc.Driver" />  
    <property name="jdbcUrl">  
        <value>${demo.datasource.slave.jdbcUrl}</value>  
    </property>  
    <property name="username" value="${demo.datasource.slave.username}" />  
    <property name="password" value="${demo.datasource.slave.password}" />  
    <property name="idleConnectionTestPeriodInMinutes" value="5" />  
    <property name="idleMaxAgeInMinutes" value="30" />  
    <property name="maxConnectionsPerPartition" value="30" />  
    <property name="minConnectionsPerPartition" value="5" />  
    <property name="partitionCount" value="2" />  
    <property name="acquireIncrement" value="5" />  
    <property name="statementsCacheSize" value="150" />  
    <property name="releaseHelperThreads" value="8" />  
    <property name="connectionTestStatement" value="select 1 from dual" />  
</bean>  
<bean id="demoSqlSessionFactory"  
    class="org.summercool.mybatis.spring.support.SqlSessionFactoryBean">  
    <property name="mainDataSource" ref="dataSourceMaster" />  
    <property name="shardDataSourceList">  
        <util:list>  
            <ref bean="dataSourceSlave" />  
        </util:list>  
    </property>  
    <property name="mapperLocations">  
        <array>  
            <value>classpath:mybatis/user-mapper.xml</value>  
        </array>  
    </property>  
    <property name="shardStrategy">  
        <map>  
            <entry key="Shard-User">  
                <value>org.summercool.mybatis.demo.shard.UserShardStrategy</value>  
            </entry>  
        </map>  
    </property>  
</bean>  
<bean id="userDao" class="org.summercool.mybatis.demo.dao.impl.UserDaoImpl">  
    <property name="sqlSessionFactory" ref="demoSqlSessionFactory"/>  
</bean>

从上面的配置文件中，可以看到，注入了两个DataSource，分别代表两个物理库。然后再添加类型为org.summercool.mybatis.spring.support.SqlSessionFactoryBean的bean描述，并将两个DataSource关联到该bean的主库和备库（备库可以有多个）字段。

同时，需要设置分表策略字段shardStrategy，该字段的类型是Map，添加分表策略时，Key即为分表策略的名称，Value则为具体的分表策略实现。如上，注册了一个名称为"fr"的分表策略实现类com.gexin.contact.utils.shard.ContactShardStrategy。

4.分表策略的实现 Java代码收藏代码 package org.summercool.mybatis.demo.shard;
import java.util.Map;
import javax.sql.DataSource;
import org.summercool.mybatis.ShardParam;
import org.summercool.mybatis.strategy.ShardStrategy;
/** *

@author Kolor */
public class UserShardStrategy extends ShardStrategy {
@Override
public DataSource getTargetDataSource() {
ShardParam shardParam = getShardParam();
//
Long param = (Long) shardParam.getShardValue();
Map<String, DataSource> map = this.getShardDataSources();
if (param > 100) {
return map.get("dataSourceSlave");
}
return getMainDataSource();
}
@Override
public String getTargetSql() {
String targetSql = getSql();
ShardParam shardParam = getShardParam();
//
Long param = (Long) shardParam.getShardValue();
String tableName = "user_" + (param % 2);
targetSql = targetSql.replaceAll("\$\[user\]\$", tableName);
return targetSql;
}
}
可以看到这个分表策略继承自org.summercool.mybatis.strategy.ShardStrategy，并实现其两个抽象方法getTargetDataSource和getTargetSql，分别代表获取目标DataSource和获取目标Sql。目标DataSource通过解析分表参数，按设计好的策略获取。

目标Sql同样通过解析分表参数，生成真正的表名，然后用字符串替换的方式获取真正的Sql。

5.Dao层实现 Java代码收藏代码 package org.summercool.mybatis.demo.dao.impl;
import org.summercool.mybatis.ShardParam;
import org.summercool.mybatis.demo.dao.UserDao;
import org.summercool.mybatis.demo.dao.entity.UserEntity;
import org.summercool.mybatis.spring.support.SqlSessionDaoSupport;
/** *

@author */
public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {
public boolean insertUser(UserEntity user) {
ShardParam shardParam = new ShardParam("Shard-User", user.getId(), user);
```
 return getSqlSession().insert("NS-User.insertUser", shardParam) > 0;  
```
}
}
Dao层实现没有特别的地方，仅有的一点就是，对于需要分表分库的操作，需要传入分表参数（ShardParam）

ShardParam shardParam = new ShardParam("Shard-User", user.getId(), user);

我们来看看ShardParam的定义：

Java代码收藏代码 package org.summercool.mybatis;
public class ShardParam {
public static final ShardParam NO_SHARD = new ShardParam();
private String name;
private Object shardValue;
private Object params;
public ShardParam() {
}
public ShardParam(String name, Object shardValue, Object params) {
super();
this.name = name;
this.shardValue = shardValue;
this.params = params;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Object getShardValue() {
return shardValue;
}
public void setShardValue(Object shardValue) {
this.shardValue = shardValue;
}
public Object getParams() {
return params;
}
public void setParams(Object params) {
this.params = params;
}
}
构造函数，第一个参数是分表分库策略的名字（即在第二小节中提到的"fr"），第二个参数是分表参数，第三个参数是真正提交到数据库的参数。

Spring事务配置 Xml代码收藏代码

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">  
    <property name="locations">  
        <list>  
            <value>classpath:config/config.properties</value>  
        </list>  
    </property>  
    <property name="fileEncoding" value="UTF-8" />  
</bean>  
   
<bean id="userService" class="org.summercool.mybatis.demo.service.impl.UserServiceImpl"/>  
   
<!-- 事务配置 -->  
<bean name="userTransactionManager"  
    class="org.summercool.mybatis.spring.support.MultiDataSourceTransactionManager">  
</bean>  
<tx:advice id="userTxAdvice" transaction-manager="userTransactionManager">  
    <tx:attributes>  
        <tx:method name="*" propagation="NOT_SUPPORTED" />  
    </tx:attributes>  
</tx:advice>  
   
<aop:config>  
    <!-- UserService事务管理 -->  
    <aop:pointcut id="userServiceOperation"  
        expression="execution(* org.summercool.mybatis.demo.service..*Service.*(..))" />  
    <aop:advisor advice-ref="userTxAdvice" pointcut-ref="userServiceOperation" />  
</aop:config>

目前只支持XA分布式事务。

evan-wu/summercool-ddl

summercool-ddl