Springboot-MyBatis 多數據源讀寫分離

1.導包

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-parent</artifactId>
       <version>2.1.4.RELEASE</version>
   </parent>
   <groupId>com.xiaobin</groupId>
   <artifactId>mysql_master_slave</artifactId>
   <version>1.0-SNAPSHOT</version>

   <properties>
       <java.version>1.8</java.version>
       <lombok.version>1.18.6</lombok.version>
       <mybatis.version>1.3.2</mybatis.version>
       <lombox.version>1.18.6</lombox.version>
   </properties>

   <dependencies>
       <!-- 添加web啓動座標 -->
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-web</artifactId>
       </dependency>
       <!-- 添加lombok工具座標 -->
       <dependency>
           <groupId>org.projectlombok</groupId>
           <artifactId>lombok</artifactId>
           <version>${lombok.version}</version>
       </dependency>
       <!-- 添加springboot 測試座標 -->
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-test</artifactId>
       </dependency>
       <!-- 添加lombox 測試座標 -->
       <dependency>
           <groupId>org.projectlombok</groupId>
           <artifactId>lombok</artifactId>
           <version>${lombox.version}</version>
       </dependency>
       <!-- 添加mybatis依賴座標 -->
       <dependency>
           <groupId>org.mybatis.spring.boot</groupId>
           <artifactId>mybatis-spring-boot-starter</artifactId>
           <version>${mybatis.version}</version>
       </dependency>
       <!-- 添加mysql驅動器座標 -->
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-jdbc</artifactId>
       </dependency>
       <!-- 添加druid數據源座標 -->
       <dependency>
           <groupId>com.alibaba</groupId>
           <artifactId>druid-spring-boot-starter</artifactId>
           <version>1.1.10</version>
       </dependency>
       <!-- 添加AOP座標 -->
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-aop</artifactId>
       </dependency>

   </dependencies>
</project>

2.application.yml配置

spring:
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        druid:
            master:
                driverClassName: com.mysql.jdbc.Driver
                username: root
                password: root
                url: jdbc:mysql://localhost:3306/master?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8
            slave:
                enable: false
                driverClassName: com.mysql.jdbc.Driver
                username: root
                password: root
                url: jdbc:mysql://localhost:3306/slave?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8

3.配置多數據源類

package com.hjl.config;

import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;

import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.myproj.common.enums.DataSourceType;
import com.myproj.framework.datasource.DynamicDataSource;

/**
 * druid 配置多數據源
 *
 * @author hjl
 */
@Configuration
public class DruidConfig {
    @Bean
    @ConfigurationProperties("spring.datasource.druid.master")
    public DataSource masterDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid.slave")
//配置爲中的spring.datasource.druid.slave.enable=true才加載
    @ConditionalOnProperty(prefix = "spring.datasource.druid.slave" , name = "enabled" , havingValue = "true")
    public DataSource slaveDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean(name = "dynamicDataSource")
    @Primary
    public DynamicDataSource dataSource(DataSource masterDataSource, DataSource slaveDataSource) {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceType.MASTER.name(), masterDataSource);
        targetDataSources.put(DataSourceType.SLAVE.name(), slaveDataSource);
        return new DynamicDataSource(masterDataSource, targetDataSources);
    }
}

4.動態數據源切換類

public class DynamicDataSource  extends AbstractRoutingDataSource {

    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }

    @Override
    protected Object determineCurrentLookupKey() {
        return getDataSource();
    }

    public static void setDataSource(String dataSource) {
        contextHolder.set(dataSource);
    }

    public static String getDataSource() {
        return contextHolder.get();
    }

    public static void clearDataSource() {
        contextHolder.remove();
    }
}

5.自定義註解類

package com.hjl.annotation;

import java.lang.annotation.*;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    String name() default "";
}

6.AOP切面類，用於判斷切換數據源

@Aspect
@Order(1)
@Component
public class DataSourceAspect {
    
    @Pointcut("@annotation(com.hjl.annotation.DataSource)")
    public void dataSourcePointCut() {

    }


    @Around("dataSourcePointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();

        //判斷方法上是否有@DataSource註解，如果有就走master數據源
        DataSource dataSource = method.getAnnotation(DataSource.class);
        if(dataSource == null){
            DynamicDataSource.setDataSource("master");
        }else {
            DynamicDataSource.setDataSource(dataSource.name());
        }

        try {
            return point.proceed();
        } finally {
            DynamicDataSource.clearDataSource();
        }
    }
}

7.main啓動類

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})
@MapperScan(basePackages = "com.hjl.mapper")
public class StartApp {
    public static void main(String[] args) {
        SpringApplication.run(StartApp.class);
    }
}