shardingJdbc专题系列(五)之Inline策略 java config 实现方式

刺骨的言语ヽ痛彻心扉 2022-12-28 12:41 256阅读 0赞

前面几篇文章我们都是通过yml配置文件的方式，简单实现了 inline模式下的分库分表。 通过yml的方式，我们需要在配置文件中配置数据源和分库分表的策略表达式。那么如果我不想在配置文件中写如此冗长的配置，能否采用java config 的方式实现呢。肯定是可以的。

本篇文章我们就来介绍通过java config的方式来重新实现inline模式下的分库分表。本次代码案例我们在git脚手架里的 sharding-inline-java 的module下进行。（git地址参看第一篇文章）

首先还是先依赖 sharding-biz, 主要是配置文件。

首先在config包下创建 MybatisPlusConfig 配置类，内容如下；  (注意：有一个ConditionOnBean注解，用来限制类的加载顺序，防止出错)

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import javax.sql.DataSource;
    
    @Configuration
    @MapperScan(basePackages = "cn.cestc.biz.mapper")
    @ConditionalOnBean(value= DataSource.class)
    public class MybatisPlusConfig {
        @Bean
        public PaginationInterceptor paginationInterceptor() {
            PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
            paginationInterceptor.setLimit(-1);
            return paginationInterceptor;
        }
    }

第二步，添加一个 shardingJdbc的配置类，用来替换原来的yml

import org.apache.shardingsphere.api.config.sharding.KeyGeneratorConfiguration;
    import org.apache.shardingsphere.api.config.sharding.ShardingRuleConfiguration;
    import org.apache.shardingsphere.api.config.sharding.TableRuleConfiguration;
    import org.apache.shardingsphere.api.config.sharding.strategy.InlineShardingStrategyConfiguration;
    import org.apache.shardingsphere.shardingjdbc.api.ShardingDataSourceFactory;
    import org.apache.shardingsphere.spring.boot.util.DataSourceUtil;
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import javax.sql.DataSource;
    import java.sql.SQLException;
    import java.util.*;
    
    /**
     * @className: ShardingDataSourceConfiguration
     * @description:
     * @author: sh.Liu
     * @date: 2020-11-03 19:23
     */
    @Configuration
    @MapperScan(basePackages = "cn.cestc.biz.mapper")
    public class ShardingDataSourceConfiguration {
    
        @Bean("shardingDataSource")
        public DataSource getShardingDataSource() throws SQLException, ReflectiveOperationException {
            ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
            // 广播表
            List<String> broadcastTables = new LinkedList<>();
            broadcastTables.add("t_user");
            broadcastTables.add("t_address");
            shardingRuleConfig.setBroadcastTables(broadcastTables);
    
            // 默认策略
            shardingRuleConfig.setDefaultDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "ds0"));
            shardingRuleConfig.setDefaultTableShardingStrategyConfig(new InlineShardingStrategyConfiguration("user_id", "t_order_${user_id % 4 + 1}"));
            // 获取user表的分片规则配置
            TableRuleConfiguration userInfoTableRuleConfiguration = getUserInfoTableRuleConfiguration();
    
            shardingRuleConfig.getTableRuleConfigs().add(userInfoTableRuleConfiguration);
            Properties props = new Properties();
            props.put("sql.show", "true");
            return ShardingDataSourceFactory.createDataSource(createDataSourceMap(), shardingRuleConfig, props);
        }
    
        /**
         * 配置真实数据源
         * @return 数据源map
         */
        private Map<String, DataSource> createDataSourceMap() throws ReflectiveOperationException {
            Map<String, DataSource> dataSourceMap = new HashMap<>();
            Map<String, Object> dataSourceProperties = new HashMap<>();
            dataSourceProperties.put("DriverClassName", "com.mysql.jdbc.Driver");
            dataSourceProperties.put("jdbcUrl", "jdbc:mysql://localhost:3306/ds0?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8");
            dataSourceProperties.put("username", "root");
            dataSourceProperties.put("password", "root");
    
            DataSource dataSource1 = DataSourceUtil.getDataSource("com.zaxxer.hikari.HikariDataSource", dataSourceProperties);
    
            Map<String, Object> dataSourceProperties2 = new HashMap<>();
            dataSourceProperties2.put("DriverClassName", "com.mysql.jdbc.Driver");
            dataSourceProperties2.put("jdbcUrl", "jdbc:mysql://localhost:3306/ds1?serverTimezone=UTC&useSSL=false&useUnicode=true&characterEncoding=UTF-8");
            dataSourceProperties2.put("username", "root");
            dataSourceProperties2.put("password", "root");
    
            DataSource dataSource2 = DataSourceUtil.getDataSource("com.zaxxer.hikari.HikariDataSource", dataSourceProperties2);
    
            dataSourceMap.put("ds0",dataSource1);
            dataSourceMap.put("ds1",dataSource2);
            return dataSourceMap;
        }
    
        /**
         * 配置user表的分片规则
         *
         * @return ser表的分片规则配置对象
         */
        private TableRuleConfiguration getUserInfoTableRuleConfiguration() {
            // 为user表配置数据节点
            TableRuleConfiguration ruleConfiguration = new TableRuleConfiguration("t_order", "ds0.t_order_$->{1..4}");
            // 设置分片键
            String shardingKey = "user_id";
            // 为user表配置分库分片策略及分片算法
            ruleConfiguration.setDatabaseShardingStrategyConfig(new InlineShardingStrategyConfiguration(shardingKey, "ds$->{user_id % 2}"));
            // 为user表配置分表分片策略及分片算法
            ruleConfiguration.setTableShardingStrategyConfig(new InlineShardingStrategyConfiguration(shardingKey, "t_order_${user_id % 4 + 1}"));
            ruleConfiguration.setKeyGeneratorConfig(new KeyGeneratorConfiguration("SNOWFLAKE", "order_id"));
            return ruleConfiguration;
        }
    }

这个类中，配置了数据源的集合，同时在getUserInfoTableRuleConfiguration 方法中配置了order表的分库分表策略，和之前yml文件中的配置都是对应的，如果有多个表，添加多个方法，在getShardingDataSource 方法中添加(add) 多个策略即可。

最关键的是启动类，需要排除一个类   @SpringBootApplication(exclude = \{SpringBootConfiguration.class\})， 注意的是 SpringBootConfiguration要选择的是 shardingjdbc包下面的这个类：代码如下

import org.apache.shardingsphere.shardingjdbc.spring.boot.SpringBootConfiguration;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /**
     * @className: ShardingInlineJavaApplication
     * @description:
     * @author: sh.Liu
     * @date: 2020-11-15 10:57
     */
    @SpringBootApplication(exclude = {SpringBootConfiguration.class})
    public class ShardingInlineJavaApplication {
        public static void main(String[] args) {
            SpringApplication.run(ShardingInlineJavaApplication.class, args);
        }
    }

好了，万事具备，接下来写一个测试的Controller, 测试一下分库分表的策略是否生效即可。

关于inline模式的分库分表到这里就告一段落了，在这一部分中，我们详细介绍了inline模式如何分库，如何分表，以及如何使用java config 实现。 下一部分我们重点研究下一种策略， standard标准策略的分库分表。