需求背景

由于最近公司新項(xiàng)目需求，可能會(huì)用到多數(shù)據(jù)源懈凹，所以我開(kāi)始研究來(lái)一下，項(xiàng)目是基于SpringBoot2搭建的，springboot2默認(rèn)使用HikariCP作為數(shù)據(jù)庫(kù)連接池,這一點(diǎn)需要注意磨总，為啥使用這個(gè)，請(qǐng)查看這個(gè)鏈接http://ju.outofmemory.cn/entry/353647來(lái)了解HikariCP連接池的性能笼沥，廢話不多說(shuō)蚪燕，上代碼。

代碼實(shí)現(xiàn)

• 數(shù)據(jù)源配置屬性

hikari.master.jdbc-url=jdbc:mysql://localhost:3306/bus_data?serverTimezone=UTC&useSSL=true
hikari.master.username=root
hikari.master.password=123456
hikari.master.maximum-pool-size=20
hikari.master.pool-name=master
hikari.master.connection-timeout=30000
hikari.master.idle-timeout=600000
hikari.master.max-lifetime=1765000

hikari.slave.jdbc-url=jdbc:mysql://localhost:3306/bus_data_read?serverTimezone=UTC&useSSL=true
hikari.slave.username=root
hikari.slave.password=123456
hikari.slave.maximum-pool-size=80
hikari.slave.pool-name=slave
hikari.slave.connection-timeout=30000
hikari.slave.idle-timeout=600000
hikari.slave.max-lifetime=1765000
hikari.slave.read-only=true

• 注入配置

/**
 * TODO
 *
 * @author zhaoqing
 * @Description
 * @createTime 2018/7/13 23:57
 */
@Component
@ConfigurationProperties(prefix = "hikari")
public class DBProperties {
    private HikariDataSource master;
    private HikariDataSource slave;

    public HikariDataSource getMaster() {
        return master;
    }

    public void setMaster(HikariDataSource master) {
        this.master = master;
    }

    public HikariDataSource getSlave() {
        return slave;
    }

    public void setSlave(HikariDataSource slave) {
        this.slave = slave;
    }
}

• 動(dòng)態(tài)切換數(shù)據(jù)源

@Slf4j
@Data
public class DataSourceContextHolder {

    /**
     * 默認(rèn)數(shù)據(jù)源
     */
    static final String DEFAULT_DS = "dataSourceFirst";

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

    // 設(shè)置數(shù)據(jù)源名
    static void setDB(String dbType) {
        log.debug("切換到{}數(shù)據(jù)源", dbType);
        contextHolder.set(dbType);
    }

    // 獲取數(shù)據(jù)源名
    static String getDB() {
        return contextHolder.get();
    }

    // 清除數(shù)據(jù)源名
    static void clearDB() {
        contextHolder.remove();
    }
}

• 創(chuàng)建動(dòng)態(tài)數(shù)據(jù)源

@Configuration
public class DataSourceConfig {

    @Autowired
    private DBProperties properties;

    @Bean(name = "dynamicSource")
    public DynamicDataSource dataSource() {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();

        // 添加數(shù)據(jù)源
        Map<Object, Object> dsMap = new HashMap<>(5);
        dsMap.put("dataSourceFirst", properties.getMaster());
        dsMap.put("dataSourceSecond", properties.getSlave());
        dynamicDataSource.setTargetDataSources(dsMap);
        return dynamicDataSource;
    }
}

• 定義注解

@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
public @interface DBSource {
    String value() default "dataSourceFirst";
}

• 用AOP實(shí)現(xiàn)切換數(shù)據(jù)源邏輯

@Aspect
@Component
public class DynamicDataSourceAspect {

    @Before("@annotation(com.zqrock.productservice.config.DBSource)")
    public void beforeSwitchDS(JoinPoint point){

        //獲得當(dāng)前訪問(wèn)的class
        Class<?> className = point.getTarget().getClass();

        //獲得訪問(wèn)的方法名
        String methodName = point.getSignature().getName();
        //得到方法的參數(shù)的類型
        Class[] argClass = ((MethodSignature)point.getSignature()).getParameterTypes();
        String dataSource = DataSourceContextHolder.DEFAULT_DS;
        try {
            // 得到訪問(wèn)的方法對(duì)象
            Method method = className.getMethod(methodName, argClass);

            // 判斷是否存在@DS注解
            if (method.isAnnotationPresent(DBSource.class)) {
                DBSource annotation = method.getAnnotation(DBSource.class);
                // 取出注解中的數(shù)據(jù)源名
                dataSource = annotation.value();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 切換數(shù)據(jù)源
        DataSourceContextHolder.setDB(dataSource);
    }
    
    @After("@annotation(com.zqrock.productservice.config.DBSource)")
    public void afterSwitchDS(JoinPoint point){
        DataSourceContextHolder.clearDB();
    }
}

• DAO配置

import com.zqrock.productservice.config.DBSource;
import com.zqrock.productservice.dao.mapper.UserMapper;
import com.zqrock.productservice.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 *
 *
 * @author zhaoqing
 * @Description
 * @createTime 2018/7/13 21:50
 */
@Repository
public class UserDao {
    private final UserMapper userMapper;

    @Autowired(required = false)
    public UserDao(UserMapper userMapper) {
        this.userMapper = userMapper;
    }

    @DBSource("dataSourceFirst")
    public List<User> getAllUsers(){
        return userMapper.getAllUsers();
    }

    @DBSource("dataSourceSecond")
    public User getUserById(int id){
        return userMapper.getUserById(id);
    }
}

至此,全部核心代碼已都貼出,有問(wèn)題請(qǐng)及時(shí)留言,歡迎一起交流!