spring boot:用shardingjdbc實現多數據源的分庫分表(shardingsphere 4.1.1/spring boot 2.3.1)

一，shardingjdbc的用途

1,官方站介紹:

Apache ShardingSphere 是一套開源的分布式數據庫中間件解決方案組成的生態圈，

它由 JDBC、Proxy 和 Sidecar（規划中）這 3 款相互獨立，卻又能夠混合部署配合使用的產品組成。

 它們均提供標准化的數據分片、分布式事務和數據庫治理功能，

可適用於如 Java 同構、異構語言、雲原生等各種多樣化的應用場景

 

2,網址:

官方站:

http://shardingsphere.apache.org/index_zh.html

官方示例：

https://github.com/apache/shardingsphere-example

官方文檔(4.x):

https://shardingsphere.apache.org/document/legacy/4.x/document/cn/overview/

 

說明：劉宏締的架構森林是一個專注架構的博客，地址：https://www.cnblogs.com/architectforest

         對應的源碼可以訪問這里獲取： https://github.com/liuhongdi/

說明：作者:劉宏締 郵箱: [e-mail]

 

二，演示項目的相關信息

1,項目地址(完整代碼):

https://github.com/liuhongdi/shardingjdbc

2,項目說明:

  兩個數據庫資源:saleorder01,saleorder02

  下面包含了相同結構的數據表各兩個,分別是:

   t_order_1,

   t_order_2,

   t_order_3,

   t_order_4

3,數據庫結構

  如圖:

  

4,項目結構:

   如圖:

 

三，配置文件說明:

1,數據庫的創建sql：

CREATE DATABASE `saleorder01` /*!40100 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci */ /*!80016 DEFAULT ENCRYPTION='N' */

CREATE DATABASE `saleorder02` /*!40100 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci */ /*!80016 DEFAULT ENCRYPTION='N' */

2,數據表的創建sql：

CREATE TABLE `t_order_1` (
 `orderId` bigint(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
 `goodsName` varchar(250) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL DEFAULT '' COMMENT 'name',
 PRIMARY KEY (`orderId`)
) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='order'

其他三個表sql相同

3,application.properties:

#shardingsphere
spring.shardingsphere.datasource.names=saleorder01,saleorder02

spring.shardingsphere.datasource.saleorder01.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.saleorder01.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.saleorder01.jdbc-url=jdbc:mysql://127.0.0.1:3306/saleorder01?characterEncoding=utf-8
spring.shardingsphere.datasource.saleorder01.username=root
spring.shardingsphere.datasource.saleorder01.password=passdemo

spring.shardingsphere.datasource.saleorder02.type=com.zaxxer.hikari.HikariDataSource
spring.shardingsphere.datasource.saleorder02.driver-class-name=com.mysql.cj.jdbc.Driver
spring.shardingsphere.datasource.saleorder02.jdbc-url=jdbc:mysql://127.0.0.1:3306/saleorder02?characterEncoding=utf-8
spring.shardingsphere.datasource.saleorder02.username=root
spring.shardingsphere.datasource.saleorder02.password=passdemo

spring.shardingsphere.sharding.default-data-source-name=saleorder01
spring.shardingsphere.sharding.default-database-strategy.standard.sharding-column=orderId
spring.shardingsphere.sharding.default-database-strategy.standard.precise-algorithm-class-name=com.shardingjdbc.demo.algorithm.DatabasePreciseShardingAlgorithm

spring.shardingsphere.sharding.binding-tables=t_order
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=saleorder0$->{1..1}.t_order_$->{1..2},saleorder0$->{2..2}.t_order_$->{3..4}
spring.shardingsphere.sharding.tables.t_order.table-strategy.standard.sharding-column=orderId
spring.shardingsphere.sharding.tables.t_order.table-strategy.standard.precise-algorithm-class-name=com.shardingjdbc.demo.algorithm.OrderTablePreciseShardingAlgorithm

spring.shardingsphere.props.sql.show=true

說明：

com.shardingjdbc.demo.algorithm.DatabasePreciseShardingAlgorithm:數據庫得到數據源的算法

com.shardingjdbc.demo.algorithm.OrderTablePreciseShardingAlgorithm:t_order表得到表名的算法

spring.shardingsphere.datasource.names=saleorder01,saleorder02:  指定數據源的名字

spring.shardingsphere.sharding.binding-tables=t_order:   指定綁定表的名字

spring.shardingsphere.props.sql.show=true：打印sql

 

四，java代碼說明

DatabasePreciseShardingAlgorithm.java

public class DatabasePreciseShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
        Long curValue = shardingValue.getValue();
        String curBase = "";
        if (curValue > 0 && curValue<=200) {
            curBase = "saleorder01";
        } else {
            curBase = "saleorder02";
        }
        return curBase;
    }
}

說明：根據id返回數據庫資源名

 

OrderTablePreciseShardingAlgorithm.java

public class OrderTablePreciseShardingAlgorithm implements PreciseShardingAlgorithm<Long> {
    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Long> shardingValue) {
        Long curValue = shardingValue.getValue();
        String curTable = "";
        if (curValue > 0 && curValue<=100) {
            curTable = "t_order_1";
        } else if (curValue > 100 && curValue<=200) {
            curTable = "t_order_2";
        } else if (curValue > 200 && curValue<=300) {
            curTable = "t_order_3";
        } else {
            curTable = "t_order_4";
        }
        return curTable;
    }
}

說明：根據id返回數據表名

 

五，效果演示

1,添加一個訂單:

訪問: /order/add/

 

2,查看訂單列表: 

訪問: /order/list/

 

六，shardingjdbc使用中的注意事項：

1，如果有的表比較小，可以存在於各個庫中，

這里可以使用公共表(廣播表):例：

spring.shardingsphere.sharding.broadcast-tables=t_dict

寫入時會寫入到各個庫，

讀取時從本地庫中讀取，可以避免跨節點的查詢

 

2,打開sql顯示，用於調試

spring.shardingsphere.props.sql.show= #是否開啟SQL顯示，默認值: false

spring.shardingsphere.props.sql.show=true

 

3，如果是用戶表分表，需要使用表內唯一的字段如：用戶名/手機號作為sharding column做拆分

 

4，即使做了分表，仍然要添加查詢時使用到的索引,

否則效率仍然會成問題

 

5,不參與分表的數據表，要指定所在的數據源:如下:

spring.shardingsphere.sharding.default-data-source-name=saleorder01

 

七，查看spring boot版本

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.3.1.RELEASE)