首先在pom文件中引入需要的依賴
<dependency>
<groupId>io.shardingjdbc</groupId>
<artifactId>sharding-jdbc-core-spring-namespace</artifactId>
<version>2.0.3</version>
</dependency>
二、新建一個sharding-jdbc.xml文件，實現分庫分表的配置
<?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">
<rdb:strategy id="tableShardingStrategy" sharding-columns="user_id" algorithm-class="com.meiren.member.common.sharding.MemberSingleKeyTableShardingAlgorithm"/>
<rdb:data-source id="shardingDataSource">
<rdb:sharding-rule data-sources="dataSource">
<rdb:table-rules>
<rdb:table-rule logic-table="member_index" actual-tables="member_index_tbl_${[0,1,2,3,4,5,6,7,8,9]}${0..9}" table-strategy="tableShardingStrategy"/>
<rdb:table-rule logic-table="member_details" actual-tables="member_details_tbl_${[0,1,2,3,4,5,6,7,8,9]}${0..9}" 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>
這里我簡單介紹下一些屬性的含義，
<rdb:strategy id="tableShardingStrategy" sharding-columns="user_id" algorithm-class="com.meiren.member.common.sharding.MemberSingleKeyTableShardingAlgorithm"/> 配置分表規則器 sharding-columns：分表規 則
依賴的名（根據user_id取模分表），algorithm-class:分表規則的實現類
<rdb:sharding-rule data-sources="dataSource"> 這里填寫關聯數據源（多個數據源用逗號隔開）,
<rdb:table-rule logic-table="member_index" actual-tables="member_index_tbl_${[0,1,2,3,4,5,6,7,8,9]}${0..9}" table-strategy="tableShardingStrategy"/> logic-table：邏輯表名（mybatis中代替的表名）actual-tables：
數據庫實際的表名，這里支持inline表達式，比如：member_index_tbl_${0..2}會解析成member_index_tbl_0，member_index_tbl_1，member_index_tbl_2；member_index_tbl_${[a,b,c]}會被解析成
member_index_tbl_a,member_index_tbl_b和member_index_tbl_c,兩種表達式一起使用的時候，會采取笛卡爾積的方式：member_index_tbl_${[a,b]}${0..2}解析為member_index_tbl_a0,member_index_tbl_a1 member_index_tbl_a2,member_index_tbl_b0,member_index_tbl_b1,member_index_tbl_b2;table-strategy:前面定義的分表規則器；
三、配置好改文件后，需要修改之前我們的spring-dataSource的幾個地方，把sqlSessionFactory和transactionManager原來關聯的dataSource統一修改為shardingDataSource（這一步作用就是把數據源全部托管給sharding去管理）
四、實現分表（分庫）邏輯，我們的分表邏輯類需要實現SingleKeyTableShardingAlgorithm接口的三個方法doBetweenSharding、doEqualSharding、doInSharding
/**
* 分表邏輯
* @author zhangwentao
*
*/
public class MemberSingleKeyTableShardingAlgorithm implements SingleKeyTableShardingAlgorithm<Long> {
/**
* sql between 規則
*/
public Collection<String> doBetweenSharding(Collection<String> tableNames, ShardingValue<Long> shardingValue) {
Collection<String> result = new LinkedHashSet<String>(tableNames.size());
Range<Long> range = (Range<Long>) shardingValue.getValueRange();
for (long i = range.lowerEndpoint(); i <= range.upperEndpoint(); i++) {
Long modValue = i % 100;
String modStr = modValue < 10 ? "0" + modValue : modValue.toString();
for (String each : tableNames) {
if (each.endsWith(modStr)) {
result.add(each);
}
}
}
return result;
}
/**
* sql == 規則
*/
public String doEqualSharding(Collection<String> tableNames, ShardingValue<Long> shardingValue) {
Long modValue = shardingValue.getValue() % 100;
String modStr = modValue < 10 ? "0" + modValue : modValue.toString();
for (String each : tableNames) {
if (each.endsWith(modStr)) {
return each;
}
}
throw new IllegalArgumentException();
}
/**
* sql in 規則
*/
public Collection<String> doInSharding(Collection<String> tableNames, ShardingValue<Long> shardingValue) {
Collection<String> result = new LinkedHashSet<String>(tableNames.size());
for (long value : shardingValue.getValues()) {
Long modValue = value % 100;
String modStr = modValue < 10 ? "0" + modValue : modValue.toString();
for (String tableName : tableNames) {
if (tableName.endsWith(modStr)) {
result.add(tableName);
}
}
}
return result;
}
}
五、以上四步，我們就完成了sharding-jdbc的搭建，我們可以寫一個測試demo來檢查我們的成果
<select id="getDetailsById" resultType="com.meiren.member.dataobject.MemberDetailsDO"
parameterType="java.lang.Long">
select user_id userId ,qq,email from member_details where user_id =#{userId} limit 1
</select>
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private
static
final
String SERVICE_PROVIDER_XML =
"/spring/member-service.xml"
;
private
static
final
String BEAN_NAME =
"idcacheService"
;
private
ClassPathXmlApplicationContext context =
null
;
IdcacheServiceImpl bean =
null
;
IdcacheDao idcacheDao;
@Before
public
void
before() {
context=
new
ClassPathXmlApplicationContext(
new
String[] {SERVICE_PROVIDER_XML});
idcacheDao=context.getBean(
"IdcacheDao"
, IdcacheDao.
class
);
}
@Test
public
void
getAllCreditActionTest() {
// int id = bean.insertIdcache();
Long s=100l;
MemberDetailsDO memberDetailsDO=idcacheDao.getDetailsById(s);
System.out.println(
"QQ---------------------"
+memberDetailsDO.getQq());
}
|
打印sql語句，輸出結果：QQ-------------------------------------100，證明成功！
注意點：這次搭建過程中，執行的時候報錯，官方文檔是有解決方案：引入 <context:property-placeholder location="classpath:/member_service.properties" ignore-unresolvable="true" /> ，引入這行代碼的時候，·必須要要把這邊管理配配置文件的bean刪除，換句話說，即Spring容器僅允許最多定義一個PropertyPlaceholderConfigurer(或<context:property-placeholder/>)，其余的會被Spring忽略掉