在Spring boot 中使用@master 设置主从数据库

基础配置

application.yml

spring:
　　datasource:
　　　　master:
　　　　　　url: jdbc:mysql://localhost:3306/master_db
　　　　　　username: root
　　　　　　password: 123456
　　　　　　driver-class-name: com.mysql.cj.jdbc.Driver
　　　　slave:
　　　　　　url: jdbc:mysql://localhost:3306/slave_db
　　　　　　username: root
　　　　　　password: 123456
　　　　　　driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
　　mapper-locations: classpath:mapper/*.xml

DataSourceConfig

package com.example.multids.config;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

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

@Configuration
public class DataSourceConfig {
    
    // 主数据源配置（前缀对应application.yml中的spring.datasource.master）
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().build();
    }

    // 从数据源配置
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource() {
        return DataSourceBuilder.create().build();
    }

    // 动态数据源路由
    @Bean
    public DataSource routingDataSource(DataSource masterDataSource, DataSource slaveDataSource) {
        AbstractRoutingDataSource routingDataSource = new AbstractRoutingDataSource() {
            @Override
            protected Object determineCurrentLookupKey() {
                return DataSourceContextHolder.getDataSourceType();
            }
        };
        
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("master", masterDataSource);
        targetDataSources.put("slave", slaveDataSource);
        
        routingDataSource.setDefaultTargetDataSource(masterDataSource);
        routingDataSource.setTargetDataSources(targetDataSources);
        return routingDataSource;
    }
}

DataSourceContextHolder

package com.example.multids.config;

public class DataSourceContextHolder {
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

    // 设置当前线程数据源类型
    public static void setDataSourceType(String dsType) {
        contextHolder.set(dsType);
    }

    // 获取当前线程数据源类型
    public static String getDataSourceType() {
        return contextHolder.get();
    }

    // 清除数据源类型
    public static void clearDataSourceType() {
        contextHolder.remove();
    }
}

Master

package com.example.multids.annotation;

import java.lang.annotation.*;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Master {
    // 标记使用主数据源
}

DataSourceAspect

package com.example.multids.aspect;

import com.example.multids.annotation.Master;
import com.example.multids.config.DataSourceContextHolder;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Aspect
@Component
@Order(-1) // 保证在事务注解前执行
public class DataSourceAspect {
    
    @Around("@annotation(master)")
    public Object around(ProceedingJoinPoint point, Master master) throws Throwable {
        try {
            DataSourceContextHolder.setDataSourceType("master");
            return point.proceed();
        } finally {
            DataSourceContextHolder.clearDataSourceType();
        }
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>
</project>