SpringBoot实现多数据源（二）【Mybatis插件】

偏执的太偏执、 2024-03-31 12:26 48阅读 0赞

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#### 二、通过 Mybatis 插件切换数据源 ####

--------------------

> 通过 Mybatis 结合插件实现读写分离的数据源

1.  配置Mybatis数据源插件
    
     *  **DynamicDataSourcePlugin**

package com.vinjcent.plugin;
    
    import com.vinjcent.config.DynamicDataSource;
    import com.vinjcent.constants.DataSourceConstants;
    import org.apache.ibatis.executor.Executor;
    import org.apache.ibatis.mapping.MappedStatement;
    import org.apache.ibatis.mapping.SqlCommandType;
    import org.apache.ibatis.plugin.Interceptor;
    import org.apache.ibatis.plugin.Intercepts;
    import org.apache.ibatis.plugin.Invocation;
    import org.apache.ibatis.plugin.Signature;
    import org.apache.ibatis.session.ResultHandler;
    import org.apache.ibatis.session.RowBounds;
    import org.springframework.stereotype.Component;
    
    
    @Component
    @Intercepts(
            {
        
                    @Signature(type = Executor.class, method = "update", args = {
        MappedStatement.class, Object.class}),
                    @Signature(type = Executor.class, method = "query", args = {
        MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
            }
    )
    public class DynamicDataSourcePlugin implements Interceptor {
        
        @Override
        public Object intercept(Invocation invocation) throws Throwable {
        
    
            // 拿到当前方法(update、query)所有参数
            Object[] objects = invocation.getArgs();
    
            // MappedStatement 封装CRUD所有的元素和SQL
            MappedStatement ms = (MappedStatement) objects[0];
    
            // 读方法
            if (ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
        
                DynamicDataSource.name.set(DataSourceConstants.READ_DATASOURCE);
            } else {
        
                // 写方法
                DynamicDataSource.name.set(DataSourceConstants.WRITE_DATASOURCE);
            }
    
            return invocation.proceed();
        }
    }

**完成上面的配置即可，因为 MybatisAutoConfiguration.class 会在构造时，自动将我们配置的 DynamicDataSourcePlugin 这个实现了 Mybatis 接口 Interceptor 的bean 进行自动注入**

1.  修改 PeopleController
    
     *  将`DynamicDataSource.name.set(DataSourceConstants.xxx);`删去即可

package com.vinjcent.config;
    
    import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
    import org.springframework.boot.context.properties.ConfigurationProperties;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import javax.sql.DataSource;
    
    @Configuration
    public class DataSourceConfiguration {
        
    
        @Bean(name = "readDatasource")
        @ConfigurationProperties(prefix = "spring.datasource.read")
        public DataSource readDatasource() {
        
            // 底层会自动拿到spring.datasource中的配置,创建一个DruidDataSource
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean(name = "writeDatasource")
        @ConfigurationProperties(prefix = "spring.datasource.write")
        public DataSource writeDatasource() {
        
            // 底层会自动拿到spring.datasource中的配置,创建一个DruidDataSource
            return DruidDataSourceBuilder.create().build();
        }
    }

1.  测试 controller 中的接口，是否能够正常进行读写分离

下一篇文章《[SpringBoot实现多数据源（三）【AOP + 自定义注解】》  
][SpringBoot_AOP _ _]

[SpringBoot]: https://blog.csdn.net/Wei_Naijia/article/details/128069664
[SpringBoot_AOP _ _]: https://blog.csdn.net/Wei_Naijia/article/details/128069769