Sharding JDBC讀寫分離實現原理及例項
一、核心功能和不支援項
核心功能
- 提供一主多從的讀寫分離配置,可獨立使用,也可配合分庫分表使用。
- 獨立使用讀寫分離支援SQL透傳。
- 同一執行緒且同一資料庫連線內,如有寫入操作,以後的讀操作均從主庫讀取,用於保證資料一致性。
- 基於Hint的強制主庫路由。
不支援項
- 主庫和從庫的資料同步(所以需要另外實現主從同步,如使用Mysql的binlog實現)。
- 主庫和從庫的資料同步延遲導致的資料不一致。
- 主庫雙寫或多寫。
- 跨主庫和從庫之間的事務的資料不一致。主從模型中,事務中讀寫均用主庫。
#涉及到的庫及表
CREATE DATABASE ds_master DEFAULT CHARACTER SET UTF8 COLLATE utf8_general_ci; CREATE DATABASE ds_slave0 DEFAULT CHARACTER SET UTF8 COLLATE utf8_general_ci; CREATE DATABASE ds_slave1 DEFAULT CHARACTER SET UTF8 COLLATE utf8_general_ci; CREATE TABLE t_user( user_id BIGINT(20) PRIMARY KEY,user_name VARCHAR(40) ); CREATE TABLE t_order( order_id BIGINT(20) PRIMARY KEY,user_id BIGINT(20),order_num VARCHAR(40) );
二、不使用Spring
引入maven依賴
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-core</artifactId>
<version>4.1.1</version>
</dependency>
這裡使用到Mysql和dbcp2資料來源
<!-- dbcp2 --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-dbcp2</artifactId> <version>2.7.0</version> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-pool2</artifactId> <version>2.7.0</version> </dependency> <!-- mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.49</version> </dependency>
基於Java編碼的規則配置
/* * 讀寫分離 * ① 插入、更新、刪除只會影響主庫的資料,即從庫的資料不會被影響(不會同步插入、更新、刪除)。因為Sharding-JDBC並沒有主從庫資料同步的功能。 * 所以我們如果使用的是MySQL,可以採用binlog的方法進行同步。總之需要開發者額外處理 * ② 查詢時,如果主庫沒有資料,從庫有資料,可以查詢到資料,所以刪除的時候必須保證主庫和從庫一起刪除。 */ // 配置真實資料來源 Map<String,DataSource> dataSourceMap = new HashMap<>(); // 配置主庫 BasicDataSource masterDataSource = new BasicDataSource(); masterDataSource.setDriverClassName("com.mysql.jdbc.Driver"); masterDataSource.setUrl("jdbc:mysql://localhost:3305/ds_master"); masterDataSource.setUsername("root"); masterDataSource.setPassword("123456"); dataSourceMap.put("ds_master",masterDataSource); // 配置第一個從庫 BasicDataSource slaveDataSource1 = new BasicDataSource(); slaveDataSource1.setDriverClassName("com.mysql.jdbc.Driver"); slaveDataSource1.setUrl("jdbc:mysql://localhost:3305/ds_slave0"); slaveDataSource1.setUsername("root"); slaveDataSource1.setPassword("123456"); dataSourceMap.put("ds_slave0",slaveDataSource1); // 配置第二個從庫 BasicDataSource slaveDataSource2 = new BasicDataSource(); slaveDataSource2.setDriverClassName("com.mysql.jdbc.Driver"); slaveDataSource2.setUrl("jdbc:mysql://localhost:3305/ds_slave1"); slaveDataSource2.setUsername("root"); slaveDataSource2.setPassword("123456"); dataSourceMap.put("ds_slave1",slaveDataSource2); // 配置讀寫分離規則 MasterSlaveRuleConfiguration masterSlaveRuleConfig = new MasterSlaveRuleConfiguration("ds_master_slave","ds_master",Arrays.asList("ds_slave0","ds_slave1")); // 獲取資料來源物件 DataSource dataSource = MasterSlaveDataSourceFactory.createDataSource(dataSourceMap,masterSlaveRuleConfig,new Properties()); Connection conn = dataSource.getConnection(); // 插入資料 //ShardingKeyGenerator keyGenerator = new SnowflakeShardingKeyGenerator(); //long orderId = ((Long) keyGenerator.generateKey()).longValue(); //long userId = 1027543L; //ShardingKeyGenerator orderGenerator = new UUIDShardingKeyGenerator(); //String orderNum = (String) orderGenerator.generateKey(); // //String insertSql = "insert into t_order(order_id,user_id,order_num) values(?,?,?)"; //PreparedStatement ps = conn.prepareStatement(insertSql); //ps.setLong(1,orderId); //ps.setLong(2,userId); //ps.setString(3,orderNum); //int result = ps.executeUpdate(); //System.out.println("執行結果數:" + result); //讀取資料 String querySql = "select * from t_order"; PreparedStatement qryPs = conn.prepareStatement(querySql); ResultSet resultSet = qryPs.executeQuery(); while (resultSet.next()){ String ud = resultSet.getString("user_id"); String om = resultSet.getString("order_num"); System.out.println(String.format("user_id = [%s],order_num = [%s]",ud,om)); } // 刪除資料 String deleteSql = "delete from t_order where user_id = 1027543"; PreparedStatement dropPs = conn.prepareStatement(deleteSql); int delResult = dropPs.executeUpdate(); System.out.println("刪除結果數:" + delResult);
基於Yaml的規則配置
配置檔案sharddb.yml,內容如下:
dataSources: ds_master: !!org.apache.commons.dbcp2.BasicDataSource driverClassName: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3305/ds_master username: root password: 123456 ds_slave0: !!org.apache.commons.dbcp2.BasicDataSource driverClassName: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3305/ds_slave0 username: root password: 123456 ds_slave1: !!org.apache.commons.dbcp2.BasicDataSource driverClassName: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3305/ds_slave1 username: root password: 123456 masterSlaveRule: name: ds_ms masterDataSourceName: ds_master slaveDataSourceNames: [ds_slave0,ds_slave1] props: sql.show: true
讀取配置檔案sharddb.yml:
ClassPathResource pathResource = new ClassPathResource("sharddb.yml"); DataSource dataSource = YamlMasterSlaveDataSourceFactory.createDataSource(pathResource.getFile()); Connection conn = dataSource.getConnection(); // 插入資料 ShardingKeyGenerator keyGenerator = new SnowflakeShardingKeyGenerator(); long orderId = ((Long) keyGenerator.generateKey()).longValue(); long userId = 1027548L; ShardingKeyGenerator orderGenerator = new UUIDShardingKeyGenerator(); String orderNum = (String) orderGenerator.generateKey(); //String insertSql = "insert into t_order(order_id,orderNum); //int result = ps.executeUpdate(); //System.out.println("執行結果數:" + result); //讀取資料 String querySql = "select * from t_order"; PreparedStatement qryPs = conn.prepareStatement(querySql); ResultSet resultSet = qryPs.executeQuery(); while (resultSet.next()) { String ud = resultSet.getString("user_id"); String om = resultSet.getString("order_num"); System.out.println(String.format("user_id = [%s],om)); }
三、使用Spring
基於Spring boot的規則配置
① 引入Maven依賴
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-boot-starter</artifactId>
<version>4.1.1</version>
</dependency>
② application.properties內容如下:
# 一主二從,一般都是部署在不同的機器上,資料庫是名稱是相同的
# jdbc:mysql://192.168.1.12:3306/am_stock
# jdbc:mysql://192.168.1.13:3306/am_stock
# jdbc:mysql://192.168.1.14:3306/am_stock
spring.shardingsphere.datasource.names=master,slave0,slave1spring.shardingsphere.datasource.master.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.master.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.master.url=jdbc:mysql://localhost:3306/ds_master
spring.shardingsphere.datasource.master.username=root
spring.shardingsphere.datasource.master.password=123456spring.shardingsphere.datasource.slave0.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.slave0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave0.url=jdbc:mysql://localhost:3306/ds_slave0
spring.shardingsphere.datasource.slave0.username=root
spring.shardingsphere.datasource.slave0.password=123456spring.shardingsphere.datasource.slave1.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.slave1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.slave1.url=jdbc:mysql://localhost:3306/ds_slave1
spring.shardingsphere.datasource.slave1.username=root
spring.shardingsphere.datasource.slave1.password=123456spring.shardingsphere.masterslave.name=ms
spring.shardingsphere.masterslave.master-data-source-name=master
spring.shardingsphere.masterslave.slave-data-source-names=slave0,slave1spring.shardingsphere.props.sql.show=true
③ 直接通過注入的方式即可使用DataSource,或者將DataSource配置在JPA、Hibernate或MyBatis中使用。
@Resource
private DataSource dataSource;
④ 基於Spring boot + JNDI的規則配置
如果您計劃使用Spring boot + JNDI的方式,在應用容器(如Tomcat)中使用Sharding-JDBC時,可使用spring.shardingsphere.datasource.${datasourceName}.jndiName來代替資料來源的一系列配置。 如:
spring.shardingsphere.datasource.names=master,slave1
spring.shardingsphere.datasource.master.jndi-name=java:comp/env/jdbc/master
spring.shardingsphere.datasource.slave0.jndi-name=jdbc/slave0
spring.shardingsphere.datasource.slave1.jndi-name=jdbc/slave1spring.shardingsphere.masterslave.name=ms
spring.shardingsphere.masterslave.master-data-source-name=master
spring.shardingsphere.masterslave.slave-data-source-names=slave0,slave1spring.shardingsphere.props.sql.show=true
以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支援我們。