SpringBoot + Mybatis 配置多数据源（Srping boot 二）

时间 2019-12-26

标签 springboot mybatis 配置数据 srping boot 栏目 Spring 繁體版

原文原文链接

前置条件，你已经配置好spring boot+mybatis，能够参考以前的博客java

实现逻辑经过注解+aop切面编程来动态更新datasourcemysql

第一步，配置多个DataSourcegit

server:
  port: 8080
freezing:
    datasource:
        name: freezing
        url: jdbc:mysql://123.57.XXX.XXX:3636/freezingdb?characterEncoding=utf8&useSSL=false&serverTimezone=UTC
        username: freezing
        password: Zgjkj2015
        # 使用druid数据源
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.jdbc.Driver
        
ucenter:
   datasource:
        name: ucenter
        url: jdbc:mysql://123.57..XXX.XXX:3636/ucenter?characterEncoding=utf8&useSSL=false&serverTimezone=UTC
        username: ucenter
        password: Zgjkj2015
        # 使用druid数据源
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.jdbc.Driver
       

## 该配置节点为独立的节点，有不少同窗容易将这个配置放在spring的节点下，致使配置没法被识别
mybatis:
  mapper-locations: classpath:mapping/*.xml  #注意：必定要对应mapper映射xml文件的所在路径
  type-aliases-package: com.hmkx.demo.model  # 注意：对应实体类的路径

第二步，定义数据源上下文管理类spring

public class DynamicDataSourceContextHolder {

    private Logger logger = Logger.getLogger(DynamicDataSourceContextHolder.class);
    //存放当前线程使用的数据源类型信息
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
    //存放数据源id
    public static List<String> dataSourceIds = new ArrayList<String>();

    //设置数据源
    public static void setDataSourceType(String dataSourceType) {
        contextHolder.set(dataSourceType);
    }

    //获取数据源
    public static String getDataSourceType() {
        return contextHolder.get();
    }

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

    //判断当前数据源是否存在
    public static boolean isContainsDataSource(String dataSourceId) {
        return dataSourceIds.contains(dataSourceId);
    }
}

第三步，经过AbstractRoutingDataSource 继承修改这个类来动态修改dataTypesql

public class DynamicDataSource extends AbstractRoutingDataSource {
    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

第四步，DataSource注册数据库

public class DynamicDataSourceRegister implements ImportBeanDefinitionRegistrar, EnvironmentAware {

    private Logger logger = Logger.getLogger(DynamicDataSourceRegister.class);

    //指定数据源类型，我这里用的druid(springboot2.0默认数据源是hikari如何想使用其余数据源能够本身配置)
//    private static final String DATASOURCE_TYPE_DEFAULT = "com.zaxxer.hikari.HikariDataSource";
    private static final String DATASOURCE_TYPE_DEFAULT = "com.alibaba.druid.pool.DruidDataSource";
    //默认数据源
    private DataSource defaultDataSource;
    //用户自定义数据源
    private Map<String, DataSource> slaveDataSources = new HashMap<>();

    @Override
    public void setEnvironment(Environment environment) {
        initDefaultDataSource(environment);
        initslaveDataSources(environment);
    }

    private void initDefaultDataSource(Environment env) {
        // 读取主数据源
        Map<String, Object> dsMap = new HashMap<>();
        dsMap.put("driver", env.getProperty("freezing.datasource.driver-class-name"));
        dsMap.put("url", env.getProperty("freezing.datasource.url"));
        dsMap.put("username", env.getProperty("freezing.datasource.username"));
        dsMap.put("password", env.getProperty("freezing.datasource.password"));
        logger.info(dsMap);
        defaultDataSource = buildDataSource(dsMap);
    }


    private void initslaveDataSources(Environment env) {
        // 读取配置文件获取更多数据源
       /* String dsPrefixs = env.getProperty("slave.datasource.names");
        for (String dsPrefix : dsPrefixs.split(",")) {
            // 多个数据源
            Map<String, Object> dsMap = new HashMap<>();
            dsMap.put("driver", env.getProperty("slave.datasource." + dsPrefix + ".driver"));
            dsMap.put("url", env.getProperty("slave.datasource." + dsPrefix + ".url"));
            dsMap.put("username", env.getProperty("slave.datasource." + dsPrefix + ".username"));
            dsMap.put("password", env.getProperty("slave.datasource." + dsPrefix + ".password"));
            DataSource ds = buildDataSource(dsMap);
            slaveDataSources.put(dsPrefix, ds);
        }*/

        Map<String, Object> dsMap = new HashMap<>();
        dsMap.put("driver", env.getProperty("ucenter.datasource.driver-class-name"));
        dsMap.put("url", env.getProperty("ucenter.datasource.url"));
        dsMap.put("username", env.getProperty("ucenter.datasource.username"));
        dsMap.put("password", env.getProperty("ucenter.datasource.password"));
        logger.info("ssssssssssssssssss"+dsMap);
        System.out.println("ssssssssssssssssss"+dsMap);
        DataSource ds = buildDataSource(dsMap);
        slaveDataSources.put("ucenter", ds);
    }

    @Override
    public void registerBeanDefinitions(AnnotationMetadata annotationMetadata, BeanDefinitionRegistry beanDefinitionRegistry) {
        Map<Object, Object> targetDataSources = new HashMap<Object, Object>();
        //添加默认数据源
        targetDataSources.put("dataSource", this.defaultDataSource);
        DynamicDataSourceContextHolder.dataSourceIds.add("dataSource");
        //添加其余数据源
        targetDataSources.putAll(slaveDataSources);
        for (String key : slaveDataSources.keySet()) {
            DynamicDataSourceContextHolder.dataSourceIds.add(key);
        }

        //建立DynamicDataSource
        GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
        beanDefinition.setBeanClass(DynamicDataSource.class);
        beanDefinition.setSynthetic(true);
        MutablePropertyValues mpv = beanDefinition.getPropertyValues();
        mpv.addPropertyValue("defaultTargetDataSource", defaultDataSource);
        mpv.addPropertyValue("targetDataSources", targetDataSources);
        //注册 - BeanDefinitionRegistry
        beanDefinitionRegistry.registerBeanDefinition("dataSource", beanDefinition);

        logger.info("Dynamic DataSource Registry");
    }

    public DataSource buildDataSource(Map<String, Object> dataSourceMap) {
        try {
            Object type = dataSourceMap.get("type");
            if (type == null) {
                type = DATASOURCE_TYPE_DEFAULT;// 默认DataSource
            }
            Class<? extends DataSource> dataSourceType;
            dataSourceType = (Class<? extends DataSource>) Class.forName((String) type);
            String driverClassName = dataSourceMap.get("driver").toString();
            String url = dataSourceMap.get("url").toString();
            String username = dataSourceMap.get("username").toString();
            String password = dataSourceMap.get("password").toString();
            // 自定义DataSource配置
            DataSourceBuilder factory = DataSourceBuilder.create().driverClassName(driverClassName).url(url)
                    .username(username).password(password).type(dataSourceType);
            return factory.build();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return null;
    }
}

到这里完成了，数据库动态切换的前置工做，接下来就是何时去切换了编程

第五步，自定义标签springboot

import java.lang.annotation.*;

/**
 * @Author hht
 * @Date 2018-12-11
 * @Description 做用于类、接口或者方法上
 */
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {
    String name();
}

第六步，监控标签的aopmybatis

/**
 * @Author hht
 * @Date 2018-12-11
 * @Description 动态数据源通知
 */
@Aspect
@Order(-1)//保证在@Transactional以前执行
@Component
public class DynamicDattaSourceAspect {

    private Logger logger = Logger.getLogger(DynamicDattaSourceAspect.class);

    //改变数据源
    @Before("@annotation(targetDataSource)")
    public void changeDataSource(JoinPoint joinPoint, TargetDataSource targetDataSource) {
        String dbid = targetDataSource.name();

        if (!DynamicDataSourceContextHolder.isContainsDataSource(dbid)) {
            //joinPoint.getSignature() ：获取链接点的方法签名对象
            logger.error("数据源 " + dbid + " 不存在使用默认的数据源 -> " + joinPoint.getSignature());
        } else {
            logger.debug("使用数据源：" + dbid);
            DynamicDataSourceContextHolder.setDataSourceType(dbid);
        }
    }

    @After("@annotation(targetDataSource)")
    public void clearDataSource(JoinPoint joinPoint, TargetDataSource targetDataSource) {
        logger.debug("清除数据源 " + targetDataSource.name() + " !");
        DynamicDataSourceContextHolder.clearDataSourceType();
    }
}

这时候基本完工，最后一步就是修改启动配置类app

package com.hmkx;

import com.hmkx.config.DynamicDataSourceRegister;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Import;

@SpringBootApplication
@MapperScan("com.hmkx.mapper")
@Import(DynamicDataSourceRegister.class)
public class SpringMybatisDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringMybatisDemoApplication.class, args);
    }
}

完成了，下面是如何使用

@Service
public class ArticleServiceImpl  implements ArticleService {


    Logger log = LoggerFactory.getLogger(ArticleServiceImpl.class);

    @Resource
    private ArticlesMapper articlesMapper;


    @Override
    public Articles getArticleById(int id) {
        //使用默认数据库
        Articles articles = articlesMapper.selectByPrimaryKey(501112);
        log.info(articles.getTitle());
        return articles;
    }

    @Override
    @TargetDataSource(name="ucenter")
    public int updateByPrimaryKey(int id) {
        //使用ucenter数据库
        ArticlesWithBLOBs art = new ArticlesWithBLOBs();
        art.setId(501112);
        art.setTitle("测试");
        int res = articlesMapper.updateByPrimaryKeySelective(art);
        return res;
    }

}

记录完了，有错误或者更好的办法欢迎指代码下载地址 https://gitee.com/huhaitao/SpringBootMybatisForManyDatabase