背景
最近让我做一个大数据的系统, 分析了一下, 麻烦的地方就是多数据源切换抽取数据. 考虑到可以跨服务器跨数据库抽数, 再整理数据, 就配置了这个动态数据源的解决方案. 在此分享给大家.
实现方案
数据库配置文件
我们项目使用的是 YAML 形式的配置文件, 采用的是 hikari 的数据库连接池. 第一步我们自然是配置多个数据库源头.
我们找到 spring 的 datasource, 在下方配置三个数据源.
- spring:
- application:
- name: dynamicDatasource
- datasource:
- test1:
- driver-class-name: com.MySQL.jdbc.Driver
- url: jdbc:MySQL://127.0.0.1:3306/test1?serverTimezone=GMT+8&characterEncoding=utf-8&useSSL=false
- username: root
- password: 123456
- test2:
- driver-class-name: com.MySQL.jdbc.Driver
- url: jdbc:MySQL://127.0.0.1:3306/test2?serverTimezone=GMT+8&characterEncoding=utf-8&useSSL=false
- username: root
- password: 123456
- test3:
- driver-class-name: com.MySQL.jdbc.Driver
- url: jdbc:MySQL://127.0.0.1:3306/test3?serverTimezone=GMT+8&characterEncoding=utf-8&useSSL=false
- username: root
- password: 123456
- hikari:
- leak-detection-threshold: 2000
定义数据源实体类
我们可以建立个 datasourceBean 文件夹专门管理数据源的实体类.
我们这里要建立三个实体类. 分别对应 test1,test2,test3
- @Configuration
- public class Test1DataSourceBean {
- @Value("${spring.datasource.test1.driver-class-name}")
- private String test1Driver;
- @Value("${spring.datasource.test1.url}")
- private String test1Url;
- @Value("${spring.datasource.test1.username}")
- private String test1Username;
- @Value("${spring.datasource.test1.password}")
- private String test1Password;
- @Bean(name="test1DataSource")
- public DataSource test1DataSource() throws Exception{
- HikariDataSource dataSource = new HikariDataSource();
- dataSource.setDriverClassName(test1Driver);
- dataSource.setJdbcUrl(test1Url);
- dataSource.setUsername(test1Username);
- dataSource.setPassword(test1Password);
- return dataSource;
- }
- }
- @Configuration
- public class Test2DataSourceBean {
- @Value("${spring.datasource.test2.driver-class-name}")
- private String test2Driver;
- @Value("${spring.datasource.test2.url}")
- private String test2Url;
- @Value("${spring.datasource.test2.username}")
- private String test2Username;
- @Value("${spring.datasource.test2.password}")
- private String test2Password;
- @Bean(name="test2DataSource")
- public DataSource test2DataSource() throws Exception{
- HikariDataSource dataSource = new HikariDataSource();
- dataSource.setDriverClassName(test2Driver);
- dataSource.setJdbcUrl(test2Url);
- dataSource.setUsername(test2Username);
- dataSource.setPassword(test2Password);
- return dataSource;
- }
- }
- @Configuration
- public class Test3DataSourceBean {
- @Value("${spring.datasource.test3.driver-class-name}")
- private String test3Driver;
- @Value("${spring.datasource.test3.url}")
- private String test3Url;
- @Value("${spring.datasource.test3.username}")
- private String test3Username;
- @Value("${spring.datasource.test3.password}")
- private String test3Password;
- @Bean(name="test3DataSource")
- public DataSource test3DataSource() throws Exception{
- HikariDataSource dataSource = new HikariDataSource();
- dataSource.setDriverClassName(test3Driver);
- dataSource.setJdbcUrl(test3Url);
- dataSource.setUsername(test3Username);
- dataSource.setPassword(test3Password);
- return dataSource;
- }
- }
定义一个枚举类管理数据源
- public enum DatabaseType {
- test1("test1", "test1"),
- test2("test2", "test2"),
- test3("test3","test3");
- private String name;
- private String value;
- DatabaseType(String name, String value){
- this.name = name;
- this.value = value;
- }
- public String getName(){
- return name;
- }
- public String getValue(){
- return value;
- }
- }
定义一个线程安全的数据源容器
- public class DatabaseContextHolder {
- private static final ThreadLocal<DatabaseType> contextHolder = new ThreadLocal<>();
- public static void setDatabaseType(DatabaseType type){
- contextHolder.set(type);
- }
- public static DatabaseType getDatabaseType(){
- return contextHolder.get();
- }
- }
定义动态数据源
- public class DynamicDataSource extends AbstractRoutingDataSource{
- protected Object determineCurrentLookupKey() {
- return DatabaseContextHolder.getDatabaseType();
- }
- }
- #### mybatis 配置类
网上的很多文章配置出来都会产生数据源循环依赖的问题, 这里解决了这个问题.
- @Configuration
- @MapperScan(basePackages="cn.test.jichi", sqlSessionFactoryRef="sessionFactory")
- public class MybatisConfig {
- /**
- * @Description: 设置动态数据源
- */
- @Bean(name="dynamicDataSource")
- @Primary
- public DynamicDataSource DataSource(
- @Qualifier("test1DataSource") DataSource test1DataSource,
- @Qualifier("test2DataSource") DataSource test2DataSource,
- @Qualifier("test3DataSource") DataSource test3DataSource){
- Map<Object, Object> targetDataSource = new HashMap<>();
- targetDataSource.put(DatabaseType.test1, test1DataSource);
- targetDataSource.put(DatabaseType.test2, test2DataSource);
- targetDataSource.put(DatabaseType.test3, test3DataSource);
- DynamicDataSource dataSource = new DynamicDataSource();
- dataSource.setTargetDataSources(targetDataSource);
- dataSource.setDefaultTargetDataSource(test1DataSource);
- return dataSource;
- }
- /**
- * @Description: 根据动态数据源创建 sessionFactory
- */
- @Bean(name="sessionFactory")
- public SqlSessionFactory sessionFactory(
- @Qualifier("test1DataSource") DataSource test1DataSource,
- @Qualifier("test2DataSource") DataSource test2DataSource,
- @Qualifier("test3DataSource") DataSource test3DataSource) throws Exception{
- SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
- // 构造方法, 解决动态数据源循环依赖问题.
- sessionFactoryBean.setDataSource(this.DataSource(test1DataSource,test2DataSource, test3DataSource));
- return sessionFactoryBean.getObject();
- }
- }
- #### 提供一个示例
- public void testDymnaicDatasource(){
- // 不切换数据源默认是自己的.
- System.out.println("----- 默认数据源");
- DemoEntity totalCount = demoMapper.getTotalCount();
- String nameCount1 = totalCount.getNameCount();
- String ageCount2 = totalCount.getAgeCount();
- System.out.println("nameCount:"+nameCount1);
- System.out.println("ageCount:"+ageCount2);
- // 数据源切换为 branch
- System.out.println("----- 数据源为 test2");
- DynamicDataSourceUtils.chooseBranchDataSource();
- Integer nameCount = demoMapper.getNameCount();
- Integer ageCount = demoMapper.getAgeCount();
- System.out.println("nameCount:"+nameCount);
- System.out.println("ageCount:"+ageCount);
- // 数据源为 basic
- System.out.println("----- 数据源为 test3");
- DynamicDataSourceUtils.chooseBasicDataSource();
- Integer ageCount1 = demoMapper.getAgeCount();
- System.out.println("ageCount:"+ageCount1);
- }
- ```
总结
至此实现了多数据源的动态切换. 可以在同一个方法里面进行操作多个数据源.