Sharding JDBC讀寫分離實現(xiàn)原理及實例
一、核心功能和不支持項
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持SQL透傳。
- 同一線程且同一數(shù)據(jù)庫連接內(nèi),如有寫入操作,以后的讀操作均從主庫讀取,用于保證數(shù)據(jù)一致性。
- 基于Hint的強制主庫路由。
不支持項
- 主庫和從庫的數(shù)據(jù)同步(所以需要另外實現(xiàn)主從同步,如使用Mysql的binlog實現(xiàn))。
- 主庫和從庫的數(shù)據(jù)同步延遲導(dǎo)致的數(shù)據(jù)不一致。
- 主庫雙寫或多寫。
- 跨主庫和從庫之間的事務(wù)的數(shù)據(jù)不一致。主從模型中,事務(wù)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>
這里使用到Mysql和dbcp2數(shù)據(jù)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>
基于Java編碼的規(guī)則配置
/* * 讀寫分離 * ① 插入、更新、刪除只會影響主庫的數(shù)據(jù),即從庫的數(shù)據(jù)不會被影響(不會同步插入、更新、刪除)。因為Sharding-JDBC并沒有主從庫數(shù)據(jù)同步的功能。 * 所以我們?nèi)绻褂玫氖荕ySQL,可以采用binlog的方法進行同步??傊枰_發(fā)者額外處理 * ② 查詢時,如果主庫沒有數(shù)據(jù),從庫有數(shù)據(jù),可以查詢到數(shù)據(jù),所以刪除的時候必須保證主庫和從庫一起刪除。 */ // 配置真實數(shù)據(jù)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(guī)則 MasterSlaveRuleConfiguration masterSlaveRuleConfig = new MasterSlaveRuleConfiguration("ds_master_slave", "ds_master", Arrays.asList("ds_slave0", "ds_slave1")); // 獲取數(shù)據(jù)源對象 DataSource dataSource = MasterSlaveDataSourceFactory.createDataSource(dataSourceMap, masterSlaveRuleConfig, new Properties()); Connection conn = dataSource.getConnection(); // 插入數(shù)據(jù) //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(zhí)行結(jié)果數(shù):" + result); //讀取數(shù)據(jù) 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)); } // 刪除數(shù)據(jù) 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(jié)果數(shù):" + delResult);
基于Yaml的規(guī)則配置
配置文件sharddb.yml,內(nèi)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
讀取配置文件sharddb.yml:
ClassPathResource pathResource = new ClassPathResource("sharddb.yml"); DataSource dataSource = YamlMasterSlaveDataSourceFactory.createDataSource(pathResource.getFile()); Connection conn = dataSource.getConnection(); // 插入數(shù)據(jù) 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, 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(zhí)行結(jié)果數(shù):" + result); //讀取數(shù)據(jù) 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)); }
三、使用Spring
基于Spring boot的規(guī)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(nèi)容如下:
# 一主二從,一般都是部署在不同的機器上,數(shù)據(jù)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 基于Spring boot + JNDI的規(guī)則配置
如果您計劃使用Spring boot + JNDI的方式,在應(yīng)用容器(如Tomcat)中使用Sharding-JDBC時,可使用spring.shardingsphere.datasource.${datasourceName}.jndiName來代替數(shù)據(jù)源的一系列配置。 如:
spring.shardingsphere.datasource.names=master,slave0,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(nèi)容,希望對大家的學習有所幫助,也希望大家多多支持腳本之家。
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