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Sharding-Jdbc组件实现分表 利用Sharding-Jdbc组件实现分表

huangheng_01 人气:0

看到了当当开源的Sharding-JDBC组件,它可以在几乎不修改代码的情况下完成分库分表的实现。摘抄其中一段介绍:

Sharding-JDBC直接封装JDBC API,可以理解为增强版的JDBC驱动,旧代码迁移成本几乎为零:

先做一个最简单的试用,不做分库,仅做分表。选择数据表bead_information,首先复制成三个表:bead_information_0、bead_information_1、bead_information_2

测试实现过程

前提:已经实现srping+mybatis对单库单表做增删改查的项目。

1、修改pom.xml增加dependency

<dependency>
  <groupId>com.dangdang</groupId>
  <artifactId>sharding-jdbc-core</artifactId>
  <version>1.4.2</version>
 </dependency>
 <dependency>
  <groupId>com.dangdang</groupId>
  <artifactId>sharding-jdbc-config-spring</artifactId>
  <version>1.4.0</version>
</dependency> 

2、新建一个sharding-jdbc.xml文件,实现分库分表的配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:context="http://www.springframework.org/schema/context" 
 xmlns:tx="http://www.springframework.org/schema/tx"
 xmlns:rdb="http://www.dangdang.com/schema/ddframe/rdb"
 xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans.xsd 
   http://www.springframework.org/schema/tx 
   http://www.springframework.org/schema/tx/spring-tx.xsd
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context.xsd
   http://www.dangdang.com/schema/ddframe/rdb 
   http://www.dangdang.com/schema/ddframe/rdb/rdb.xsd">
 
 
 
 <!-- 配置数据源 -->
 <bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
 <property name="url" value="jdbc:mysql://localhost:3306/beadhouse" />
 <property name="username" value="root" />
 <property name="password" value="123456" />
 </bean>
   
 <rdb:strategy id="tableShardingStrategy" sharding-columns="id" algorithm-class="com.springdemo.utill.MemberSingleKeyTableShardingAlgorithm"/>
 
 <rdb:data-source id="shardingDataSource">
 <rdb:sharding-rule data-sources="dataSource">
  <rdb:table-rules>
  <rdb:table-rule logic-table="bead_information" actual-tables="bead_information_${0..2}" table-strategy="tableShardingStrategy"/>
  </rdb:table-rules>
 </rdb:sharding-rule>
 </rdb:data-source>
 
 <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
 <property name="dataSource" ref="shardingDataSource" />
 </bean>
</beans>

3、将文件引入spring配置文件中。

需要修改几个地方,把sqlSessionFactory和transactionManager原来关联的dataSource统一修改为shardingDataSource(这一步作用就是把数据源全部托管给sharding去管理)

4、实现分表(分库)逻辑,我们的分表逻辑类需要实现SingleKeyTableShardingAlgorithm接口的三个方法doBetweenSharding、doEqualSharding、doInSharding

(取模除数需要按照自己需求改变,我这里分3个表,所以除以3)

import java.util.Collection;
import java.util.LinkedHashSet;
import com.dangdang.ddframe.rdb.sharding.api.ShardingValue;
import com.dangdang.ddframe.rdb.sharding.api.strategy.table.SingleKeyTableShardingAlgorithm;
import com.google.common.collect.Range;
public class MemberSingleKeyTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm<Integer> {

 @Override
 public Collection<String> doBetweenSharding(Collection<String> tableNames, ShardingValue<Integer> shardingValue) {
 Collection<String> result = new LinkedHashSet<String>(tableNames.size());
 Range<Integer> range = (Range<Integer>) shardingValue.getValueRange();
 for (Integer i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
  Integer modValue = i % 3;
  String modStr = modValue < 3 ? "" + modValue : modValue.toString();
  for (String each : tableNames) {
  if (each.endsWith(modStr)) {
   result.add(each);
  }
  }
 }
 return result;
 }
 @Override
 public String doEqualSharding(Collection<String> tableNames, ShardingValue<Integer> shardingValue) {
 Integer modValue = shardingValue.getValue() % 3;
 String modStr = modValue < 3 ? "" + modValue : modValue.toString();
 for (String each : tableNames) {
  if (each.endsWith(modStr)) {
  return each;
  }
 }
 throw new IllegalArgumentException();
 }
 @Override
 public Collection<String> doInSharding(Collection<String> tableNames, ShardingValue<Integer> shardingValue) {
 Collection<String> result = new LinkedHashSet<String>(tableNames.size());
 for (Integer value : shardingValue.getValues()) {
  Integer modValue = value % 3;
  String modStr = modValue < 3 ? "" + modValue : modValue.toString();
  for (String tableName : tableNames) {
  if (tableName.endsWith(modStr)) {
   result.add(tableName);
  }
  }
 }
 return result;
 }
}

5、配置完成,可以实现增删改查测试。

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