private Map<Object, DataSource> resolvedDataSources;

resolvedDataSources.put("master",主庫(kù)數(shù)據(jù)源);
resolvedDataSources.put("salave",從庫(kù)數(shù)據(jù)源);

protected abstract Object determineCurrentLookupKey();

package com.javacode2018.readwritesplit.base;
public enum DsType {
    MASTER, SLAVE;
}

package com.javacode2018.readwritesplit.base;
public class DsTypeHolder {
    private static ThreadLocal<DsType> dsTypeThreadLocal = new ThreadLocal<>();
    public static void master() {
        dsTypeThreadLocal.set(DsType.MASTER);
    }
    public static void slave() {
        dsTypeThreadLocal.set(DsType.SLAVE);
    }
    public static DsType getDsType() {
        return dsTypeThreadLocal.get();
    }
    public static void clearDsType() {
        dsTypeThreadLocal.remove();
    }
}

package com.javacode2018.readwritesplit.base;
//需要實(shí)現(xiàn)讀寫分離的service需要實(shí)現(xiàn)該接口
public interface IService {
}

package com.javacode2018.readwritesplit.base;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.lang.Nullable;
public class ReadWriteDataSource extends AbstractRoutingDataSource {
    @Nullable
    @Override
    protected Object determineCurrentLookupKey() {
        return DsTypeHolder.getDsType();
    }
}

package com.javacode2018.readwritesplit.base;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import java.util.Objects;
@Aspect
@Order(Integer.MAX_VALUE - 2) //@1
@Component
public class ReadWriteInterceptor {
    @Pointcut("target(IService)")
    public void pointcut() {
    }
    //獲取當(dāng)前目標(biāo)方法的最后一個(gè)參數(shù)
    private Object getLastArgs(final ProceedingJoinPoint pjp) {
        Object[] args = pjp.getArgs();
        if (Objects.nonNull(args) && args.length > 0) {
            return args[args.length - 1];
        } else {
            return null;
        }
    }
    @Around("pointcut()")
    public Object around(final ProceedingJoinPoint pjp) throws Throwable {
        //判斷是否是第一次進(jìn)來(lái),用于處理事務(wù)嵌套
        boolean isFirst = false;
        try {
            if (DsTypeHolder.getDsType() == null) {
                isFirst = true;
            }
            if (isFirst) {
                Object lastArgs = getLastArgs(pjp);
                if (DsType.SLAVE.equals(lastArgs)) {
                    DsTypeHolder.slave();
                } else {
                    DsTypeHolder.master();
                }
            }
            return pjp.proceed();
        } finally {
            //退出的時(shí)候，清理
            if (isFirst) {
                DsTypeHolder.clearDsType();
            }
        }
    }
}

package com.javacode2018.readwritesplit.base;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@Configuration
@EnableAspectJAutoProxy //@1
@EnableTransactionManagement(proxyTargetClass = true, order = Integer.MAX_VALUE - 1) //@2
@ComponentScan(basePackageClasses = IService.class) //@3
public class ReadWriteConfiguration {
}

package com.javacode2018.readwritesplit.base;
import org.springframework.context.annotation.Import;
import java.lang.annotation.*;
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(ReadWriteConfiguration.class) //@1
public @interface EnableReadWrite {
}

DROP DATABASE IF EXISTS javacode2018_master;
CREATE DATABASE IF NOT EXISTS javacode2018_master;
USE javacode2018_master;
DROP TABLE IF EXISTS t_user;
CREATE TABLE t_user (
  id   INT PRIMARY KEY       AUTO_INCREMENT,
  name VARCHAR(256) NOT NULL DEFAULT ''
  COMMENT '姓名'
);
INSERT INTO t_user (name) VALUE ('master庫(kù)');
DROP DATABASE IF EXISTS javacode2018_slave;
CREATE DATABASE IF NOT EXISTS javacode2018_slave;
USE javacode2018_slave;
DROP TABLE IF EXISTS t_user;
CREATE TABLE t_user (
  id   INT PRIMARY KEY       AUTO_INCREMENT,
  name VARCHAR(256) NOT NULL DEFAULT ''
  COMMENT '姓名'
);
INSERT INTO t_user (name) VALUE ('slave庫(kù)');

package com.javacode2018.readwritesplit.demo1;

import com.javacode2018.readwritesplit.base.DsType;
import com.javacode2018.readwritesplit.base.EnableReadWrite;
import com.javacode2018.readwritesplit.base.ReadWriteDataSource;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

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

@EnableReadWrite //@1
@Configuration
@ComponentScan
public class MainConfig {
    //主庫(kù)數(shù)據(jù)源
    @Bean
    public DataSource masterDs() {
        org.apache.tomcat.jdbc.pool.DataSource dataSource = new org.apache.tomcat.jdbc.pool.DataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/javacode2018_master?characterEncoding=UTF-8");
        dataSource.setUsername("root");
        dataSource.setPassword("root123");
        dataSource.setInitialSize(5);
        return dataSource;
    }

    //從庫(kù)數(shù)據(jù)源
    @Bean
    public DataSource slaveDs() {
        org.apache.tomcat.jdbc.pool.DataSource dataSource = new org.apache.tomcat.jdbc.pool.DataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/javacode2018_slave?characterEncoding=UTF-8");
        dataSource.setUsername("root");
        dataSource.setPassword("root123");
        dataSource.setInitialSize(5);
        return dataSource;
    }

    //讀寫分離路由數(shù)據(jù)源
    @Bean
    public ReadWriteDataSource dataSource() {
        ReadWriteDataSource dataSource = new ReadWriteDataSource();
        //設(shè)置主庫(kù)為默認(rèn)的庫(kù)，當(dāng)路由的時(shí)候沒(méi)有在datasource那個(gè)map中找到對(duì)應(yīng)的數(shù)據(jù)源的時(shí)候，會(huì)使用這個(gè)默認(rèn)的數(shù)據(jù)源
        dataSource.setDefaultTargetDataSource(this.masterDs());
        //設(shè)置多個(gè)目標(biāo)庫(kù)
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DsType.MASTER, this.masterDs());
        targetDataSources.put(DsType.SLAVE, this.slaveDs());
        dataSource.setTargetDataSources(targetDataSources);
        return dataSource;
    }

    //JdbcTemplate，dataSource為上面定義的注入讀寫分離的數(shù)據(jù)源
    @Bean
    public JdbcTemplate jdbcTemplate(@Qualifier("dataSource") DataSource dataSource) {
        return new JdbcTemplate(dataSource);
    }

    //定義事務(wù)管理器，dataSource為上面定義的注入讀寫分離的數(shù)據(jù)源
    @Bean
    public PlatformTransactionManager transactionManager(@Qualifier("dataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

package com.javacode2018.readwritesplit.demo1;
import com.javacode2018.readwritesplit.base.DsType;
import com.javacode2018.readwritesplit.base.IService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import java.util.List;
@Component
public class UserService implements IService {
    @Autowired
    private JdbcTemplate jdbcTemplate;
    @Autowired
    private UserService userService;
    @Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
    public String getUserNameById(long id, DsType dsType) {
        String sql = "select name from t_user where id=?";
        List<String> list = this.jdbcTemplate.queryForList(sql, String.class, id);
        return (list != null && list.size() > 0) ? list.get(0) : null;
    }
    //這個(gè)insert方法會(huì)走主庫(kù)，內(nèi)部的所有操作都會(huì)走主庫(kù)
    @Transactional
    public void insert(long id, String name) {
        System.out.println(String.format("插入數(shù)據(jù){id:%s, name:%s}", id, name));
        this.jdbcTemplate.update("insert into t_user (id,name) values (?,?)", id, name);
        String userName = this.userService.getUserNameById(id, DsType.SLAVE);
        System.out.println("查詢結(jié)果：" + userName);
    }
}

package com.javacode2018.readwritesplit.demo1;
import com.javacode2018.readwritesplit.base.DsType;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Demo1Test {
    UserService userService;
    @Before
    public void before() {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
        context.register(MainConfig.class);
        context.refresh();
        this.userService = context.getBean(UserService.class);
    }
    @Test
    public void test1() {
        System.out.println(this.userService.getUserNameById(1, DsType.MASTER));
        System.out.println(this.userService.getUserNameById(1, DsType.SLAVE));
    }
    @Test
    public void test2() {
        long id = System.currentTimeMillis();
        System.out.println(id);
        this.userService.insert(id, "張三");
    }
}