ShardingSphere-Sharding-JDBC-4.0.×版+Spring+Mybatis+XML Namespace配置分庫分表（十三）

1.Spring MVC,Spring,Mybatis+XML Namespache配置

     關於這個部分如何配置，大家可以參考下Jeesite 2.×框架，或者網上找尋相關腳手架項目，這裏不做過多介紹。

２.配置applicationContext.xml和mybatis和sharding-jdbc的xml文件

applicationContext.xml加入如下配置文件：

<!-- Mybatis -->
    <import resource="classpath:mybatis-spring-sharding.xml"/>

mybatis-spring-shading.xml文件如下：

<?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:mybatis-spring="http://mybatis.org/schema/mybatis-spring" 
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:sharding="http://shardingsphere.apache.org/schema/shardingsphere/sharding"
    xmlns:bean="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd    
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd    
        http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring-1.2.xsd    
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
        http://shardingsphere.apache.org/schema/shardingsphere/sharding http://shardingsphere.apache.org/schema/shardingsphere/sharding/sharding.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">
        
    <context:component-scan
            base-package="cn.com.*.*.usemybatis.*" />
            
    <bean id="sharding_0" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="username" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
    </bean>

    <bean id="sharding_1" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
        <property name="jdbcUrl" value="${jdbc.shardingurl}" />
        <property name="username" value="${jdbc.shardingusername}" />
        <property name="password" value="${jdbc.shardingpassword}" />
    </bean>
    
    <bean id="preciseModuloDatabaseShardingAlgorithm" class="cn.com.*.*.component.usemybatis.algorithm.PreciseModuloShardingDatabaseAlgorithm" />
    
    <sharding:standard-strategy id="databaseStrategy" sharding-column="work_id" precise-algorithm-ref="preciseModuloDatabaseShardingAlgorithm" />
    <!-- <sharding:inline-strategy id="databaseStrategy" sharding-column="work_id" algorithm-expression="sharding_${id % 2}" /> -->
    <sharding:inline-strategy id="messageTableStrategy" sharding-column="id" algorithm-expression="tb_message${id % 2}" />
    <!-- <sharding:inline-strategy id="orderItemTableStrategy" sharding-column="order_id" algorithm-expression="t_order_item_${order_id % 2}" /> -->
    
    <bean:properties id="properties">
        <prop key="worker.id">123</prop>
    </bean:properties>
    
    <sharding:key-generator id="messageKeyGenerator" type="SNOWFLAKE" column="id" props-ref="properties"/>
    <!-- <sharding:key-generator id="itemKeyGenerator" type="SNOWFLAKE" column="order_item_id" props-ref="properties" /> -->
    
    <sharding:data-source id="shardingDataSource">
        <sharding:sharding-rule data-source-names="sharding_0, sharding_1">
            <sharding:table-rules>
                <sharding:table-rule logic-table="tb_message" actual-data-nodes="sharding_${0..1}.tb_message${0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="messageTableStrategy" key-generator-ref="messageKeyGenerator" />
                <!-- <sharding:table-rule logic-table="t_order_item" actual-data-nodes="demo_ds_${0..1}.t_order_item_${0..1}" database-strategy-ref="databaseStrategy" table-strategy-ref="orderItemTableStrategy" key-generator-ref="itemKeyGenerator" /> -->
            </sharding:table-rules>
            <sharding:binding-table-rules>
                <!-- <sharding:binding-table-rule logic-tables="t_order,t_order_item"/> -->
                <sharding:binding-table-rule logic-tables="tb_message"/>
            </sharding:binding-table-rules>
            <!-- <sharding:broadcast-table-rules>
                <sharding:broadcast-table-rule table="t_address"/>
            </sharding:broadcast-table-rules> -->
        </sharding:sharding-rule>
        <sharding:props>
            <prop key="sql.show">true</prop>
        </sharding:props>
    </sharding:data-source>
    
    <bean id="transactionMybatisManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="shardingDataSource" />
    </bean>
    
    <!--使用註解事務管理 ，爲添加mybatis添加 -->
    <tx:annotation-driven transaction-manager="transactionMybatisManager" />

    <!-- 配置SqlSessionFactory對象，爲添加mybatis添加 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入數據庫連接池 -->
        <property name="dataSource" ref="shardingDataSource" />
        <!-- 配置MyBaties全局配置文件:mybatis-config.xml -->
        <property name="configLocation" value="classpath:mybatis-config.xml" />
        <!-- 掃描entity包 使用別名 -->
        <!-- <property name="typeAliasesPackage" value="cn.com.*.*.component.portal.message.model" /> -->
        <!-- 掃描sql配置文件:mapper需要的xml文件 -->
        <!-- <property name="mapperLocations" value="cn.com.*.*.component.usemybatis.dao.*.xml" /> -->
    </bean>

    <!-- 配置掃描Dao接口包，動態實現Dao接口，注入到spring容器中，爲添加mybatis添加 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
        <!-- 給出需要掃描Dao接口包 -->
        <property name="basePackage" value="cn.com.*.*.component.usemybatis.dao" />
    </bean>
</beans> 

mybatis配置如下如下：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<!-- 配置全局屬性 -->
	<settings>
		<!-- 使全局的映射器啓用或禁用緩存。 -->
		<setting name="cacheEnabled" value="true" />

		<!-- 全局啓用或禁用延遲加載。當禁用時，所有關聯對象都會即時加載。 -->
		<setting name="lazyLoadingEnabled" value="true" />

		<!-- 當啓用時，有延遲加載屬性的對象在被調用時將會完全加載任意屬性。否則，每種屬性將會按需要加載。 -->
		<setting name="aggressiveLazyLoading" value="true" />

		<!-- 是否允許單條sql 返回多個數據集 (取決於驅動的兼容性) default:true -->
		<setting name="multipleResultSetsEnabled" value="true" />

		<!-- 是否可以使用列的別名 (取決於驅動的兼容性) default:true -->
		<setting name="useColumnLabel" value="true" />

		<!-- 允許JDBC 生成主鍵。需要驅動器支持。如果設爲了true，這個設置將強制使用被生成的主鍵，有一些驅動器不兼容不過仍然可以執行。 default:false -->
		<setting name="useGeneratedKeys" value="false" />

		<!-- 指定 MyBatis 如何自動映射 數據基表的列 NONE：不隱射 PARTIAL:部分 FULL:全部 -->
		<setting name="autoMappingBehavior" value="PARTIAL" />

		<!-- 這是默認的執行類型 （SIMPLE: 簡單； REUSE: 執行器可能重複使用prepared statements語句；BATCH: 執行器可以重複執行語句和批量更新） -->
		<setting name="defaultExecutorType" value="SIMPLE" />

		<!-- 使用駝峯命名法轉換字段。 -->
		<setting name="mapUnderscoreToCamelCase" value="true" />

		<!-- 設置但JDBC類型爲空時,某些驅動程序 要指定值,default:OTHER，插入空值時不需要指定類型 -->
		<setting name="jdbcTypeForNull" value="NULL" />
	</settings>
	<typeAliases>
		<package name="cn.com.*.*.component.usermybatis.model" />
	</typeAliases>
	<mappers>
		<mapper resource="cn/com/**/component/usemybatis/dao/MessageMyBatisDao.xml" />
	</mappers>
</configuration>

    3對應Oracle的數據庫如下說明，有兩個schema，每個schema有下面兩個表：

-- Create table
create table TB_MESSAGE0
(
  id                   NUMBER(20) not null,
  sender_id            VARCHAR2(64),
  sender_name          VARCHAR2(50),
  create_time          DATE,
  work_id              NUMBER(1)
)

-- Create table
create table TB_MESSAGE1
(
  id                   NUMBER(20) not null,
  sender_id            VARCHAR2(64),
  sender_name          VARCHAR2(50),
  create_time          DATE,
  work_id              NUMBER(1)
)

4.最後使用dao文件的save方法測試下，dao文件和xml具體代碼如下：

package cn.com.*.*.component.usemybatis.dao;

import java.math.BigDecimal;

import org.springframework.stereotype.Repository;

import cn.com.*.*.component.usemybatis.model.TbMessageMybatisEntity;

@Repository
public interface UnifiedMessageMybatisDao {
	public void save(TbMessageMybatisEntity tbGbUnifiedMessagePo);
	public TbMessageMybatisEntity get(Double id);
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.com.*.*.component.usemybatis.dao.MessageMybatisDao">
	<insert id="save" parameterType="cn.com.*.*.component.usemybatis.model.TbMessageMybatisEntity">
		INSERT INTO tb_message (id, work_id,sender_id, sender_name,
		create_time)
		VALUES
		(
		#{id},#{workId},#{senderId},#{senderName},#{createTime}
		)
	</insert>

	<select id="get" parameterType="long"
		resultType="cn.com.*.*.component.usemybatis.model.TbMessageMybatisEntity">
		select * from tb_message where id = #{id}
	</select>
</mapper>

5.自己實現雪花算法，在調用save方法的使用使用這個雪花算法，配置的雪花算法沒有生效，暫時還不清楚是什麼原因導致，後續跟蹤。

/**
     * 起始的時間戳
     */
    private final static long START_STMP = 1480166465631L;

    /**
     * 每一部分佔用的位數
     */
    private final static long SEQUENCE_BIT = 12; //序列號佔用的位數
    private final static long MACHINE_BIT = 5;   //機器標識佔用的位數
    private final static long DATACENTER_BIT = 5;//數據中心佔用的位數

    /**
     * 每一部分的最大值
     */
    private final static long MAX_DATACENTER_NUM = -1L ^ (-1L << DATACENTER_BIT);
    private final static long MAX_MACHINE_NUM = -1L ^ (-1L << MACHINE_BIT);
    private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);

    /**
     * 每一部分向左的位移
     */
    private final static long MACHINE_LEFT = SEQUENCE_BIT;
    private final static long DATACENTER_LEFT = SEQUENCE_BIT + MACHINE_BIT;
    private final static long TIMESTMP_LEFT = DATACENTER_LEFT + DATACENTER_BIT;

    private static long datacenterId;  //數據中心
    private static long machineId;     //機器標識
    private static long sequence = 0L; //序列號
    private static long lastStmp = -1L;//上一次時間戳

    public SnowFlakeIdKeyGenerator(long datacenterId, long machineId) {
        if (datacenterId > MAX_DATACENTER_NUM || datacenterId < 0) {
            throw new IllegalArgumentException("datacenterId can't be greater than MAX_DATACENTER_NUM or less than 0");
        }
        if (machineId > MAX_MACHINE_NUM || machineId < 0) {
            throw new IllegalArgumentException("machineId can't be greater than MAX_MACHINE_NUM or less than 0");
        }
    }

    /**
     * 產生下一個ID
     *
     * @return
     */
    public static synchronized long nextId() {
        long currStmp = getNewstmp();
        if (currStmp < lastStmp) {
            throw new RuntimeException("Clock moved backwards.  Refusing to generate id");
        }

        if (currStmp == lastStmp) {
            //相同毫秒內，序列號自增
            sequence = (sequence + 1) & MAX_SEQUENCE;
            //同一毫秒的序列數已經達到最大
            if (sequence == 0L) {
                currStmp = getNextMill();
            }
        } else {
            //不同毫秒內，序列號置爲0
        	Random random=new Random();
            sequence = random.nextInt(2);
        }

        lastStmp = currStmp;

        return (currStmp - START_STMP) << TIMESTMP_LEFT //時間戳部分
                | datacenterId << DATACENTER_LEFT       //數據中心部分
                | machineId << MACHINE_LEFT             //機器標識部分
                | sequence;                             //序列號部分
    }

    private static long getNextMill() {
        long mill = getNewstmp();
        while (mill <= lastStmp) {
            mill = getNewstmp();
        }
        return mill;
    }

    private static long getNewstmp() {
        return System.currentTimeMillis();
    }

    public static void main(String[] args) {
    	//SnowFlakeIdKeyGenerator snowFlake = new SnowFlakeIdKeyGenerator(2, 3);

        long start = System.currentTimeMillis();
        for (int i = 0; i < 1000000; i++) {
            System.out.println(SnowFlakeIdKeyGenerator.nextId());
        }

        System.out.println(System.currentTimeMillis() - start);


    }

具體調用方法：

SnowFlakeIdKeyGenerator snowFlakeIdKeyGenerator = new SnowFlakeIdKeyGenerator(1, 1);
            unifiedMessageShardingPo.setId(snowFlakeIdKeyGenerator.nextId()

6.PreciseModuloShardingTableAlgorithm.java來源於https://github.com/apache/incubator-shardingsphere-example項目裏面。

7.最後使用mvc寫一個controller即可，這裏省略了，目前只包含保存，如何讀後面給大家介紹，或者參考spring boot這兩篇文章

https://blog.csdn.net/qq_40102894/article/details/96302535

https://my.oschina.net/u/4034639/blog/3079441/print