springBoot集成读写分离

git地址： https://github.com/leezhang0525/boot
branch：1.1.1dynamicDataSource
本文档持续更新，目标为多组件系统，常用组件集成完毕后，后续会添加分布式内容。

1、说明

这里使用主从数据源，主从备份没有做，具体实现自行百度，这里简单使用两个数据库实现主从数据源

2、yml文件添加数据源

server:
  port: 8081
spring:
  datasource:
    master:
      url: jdbc:mysql://localhost:3306/pay?characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useLocalSessionState=true
      username: root
      password: 123456
      driver-class-name: com.mysql.jdbc.Driver
      type: com.alibaba.druid.pool.DruidDataSource
    slave:
      url: jdbc:mysql://localhost:3306/payslave?characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useLocalSessionState=true
      username: root
      password: 123456
      driver-class-name: com.mysql.jdbc.Driver
      type: com.alibaba.druid.pool.DruidDataSource

3、自定义主从数据源枚举

package com.zhangsan.boot.enums.core;
/**
 * 数据源枚举
 */
public enum DataSourceType {
    MASTER("master"),
    SLAVE("slave");
    private String value;
    DataSourceType(String value) {
        this.value = value;
    }
    public String getValue() {
        return value;
    }
}

4、新建动态数据源

1、数据源key值处理器

package com.zhangsan.boot.config;
import com.zhangsan.boot.enums.core.DataSourceType;
/**
 * 数据源处理器
 */
public class DataSourceContextHolder {
    private DataSourceContextHolder(){}
    private static final ThreadLocal<String>  holder = new ThreadLocal<>();
    public static void putDataSource(DataSourceType dataSourceType) {
        holder.set(dataSourceType.getValue());
    }
    public static String getDataSource() {
        return holder.get();
    }
    public static void clearDataSource() {
        holder.remove();
    }
}

2、编写DynamicDataSource类

继承 AbstractRoutingDataSource类，重写determineCurrentLookupKey方法

package com.zhangsan.boot.config;
import com.zhangsan.boot.enums.core.DataSourceType;
import org.apache.commons.lang3.StringUtils;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
 * 自定义动态数据源路由
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
    /**
     *
     * @return Map<Object, DataSource> resolvedDataSources key值
     */
    @Override
    protected Object determineCurrentLookupKey() {
        if(StringUtils.isNotBlank(DataSourceContextHolder.getDataSource())){
            return DataSourceContextHolder.getDataSource();
        }
        // 默认主库
        return DataSourceType.MASTER.getValue();
    }
}

3、注入动态数据源

重写DruidConfig.java类

package com.zhangsan.boot.config;
import com.alibaba.druid.pool.DruidDataSource;
import com.zhangsan.boot.enums.core.DataSourceType;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
@Configuration
public class DruidConfig {
    public static final String MAPPER_BASE_PACKAGE = "com.zhangsan.boot.dao";
    public static final String ENTITY_BASE_PACKAGE = "com.zhangsan.boot.entity";
    /**
     * 主数据源
     * @return
     */
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource(){
        return new DruidDataSource();
    }
    /**
     * 从数据源
     * @return
     */
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource(){
        return new DruidDataSource();
    }
    /**
     * 动态数据源
     * @return
     */
    @Bean
    @DependsOn({ "masterDataSource", "slaveDataSource"})
    @Primary
    public DataSource dynamicDataSource() {
        DynamicDataSource dataSource = new DynamicDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceType.MASTER.getValue(), masterDataSource());
        targetDataSources.put(DataSourceType.SLAVE.getValue(), slaveDataSource());
        dataSource.setTargetDataSources(targetDataSources);
        // 这里不需要重复添加默认数据源，DynamicDataSource类中已经制定默认主数据源key
        return dataSource;
    }
    @Bean
    public SqlSessionFactory sqlSessionFactory (@Qualifier("dynamicDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setTypeAliasesPackage(ENTITY_BASE_PACKAGE);
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath*:mappers/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }
    /**
     * mapperScannerConfigurer
     * @return
     */
    @Bean
    public static MapperScannerConfigurer mapperScannerConfigurer() {
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setBasePackage(MAPPER_BASE_PACKAGE);
        mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");
        return mapperScannerConfigurer;
    }
    @Bean
    public DataSourceTransactionManager transactionManager(@Qualifier("dynamicDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

5、自定义注解实现动态数据源

1、添加自定义注解

package com.zhangsan.boot.annotation;
import com.zhangsan.boot.enums.core.DataSourceType;
import java.lang.annotation.*;
/**
 * 主从库注解
 */
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface DataSource {
    DataSourceType value() default DataSourceType.MASTER;
}

2、编写切面管理注解

给自定义注解加上切面，通过注解管理和制定数据源

package com.zhangsan.boot.aspect;
import com.zhangsan.boot.annotation.DataSource;
import com.zhangsan.boot.config.DataSourceContextHolder;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
@Aspect
@Component
@Order(Ordered.HIGHEST_PRECEDENCE + 1)
@Slf4j
public class DataSourceAspect {
    @Around("execution(public * com.zhangsan.boot.service..*.*(..)) && @annotation(com.zhangsan.boot.annotation.DataSource) && @annotation(dataSource)")
    public Object setDataSource(ProceedingJoinPoint joinPoint, DataSource dataSource) throws Throwable {
        try {
            log.info("执行了数据路由切面，当前为:{}",dataSource.value());
            DataSourceContextHolder.putDataSource(dataSource.value());
            return joinPoint.proceed();
        } finally {
            DataSourceContextHolder.clearDataSource();
            log.info("清理了数据路由切面，threadLocal中dataSource为:{}",DataSourceContextHolder.getDataSource());
        }
    }
}

6、编写测试类测试

    /**
     * 默认主库
     * @param id
     * @return
     */
    @Override
    @DataSource(DataSourceType.MASTER)
    public TPadDevice masterGetById(Long id) {
        return tPadDeviceMapper.selectByPrimaryKey(id);
    }
    /**
     * 从库
     * @param id
     * @return
     */
    @Override
    @DataSource(DataSourceType.SLAVE)
    public TPadDevice salverGetById(Long id) {
        return tPadDeviceMapper.selectByPrimaryKey(id);
    }

TestController.java

    @GetMapping("/masterDataSource")
    public TPadDevice dynamicDataSourceTest(Long id){
        log.info("这是测试");
        TPadDevice padDevice = padDeviceService.masterGetById(id);
        return padDevice;
    }
    @GetMapping("/slaveDataSource")
    public TPadDevice slaveDataSource(Long id){
        log.info("这是测试");
        TPadDevice padDevice = padDeviceService.salverGetById(id);
        return padDevice;
    }

测试成功(不同库中，表名相同的表记录不同)