spring boot jpa动态切换数据库

柔光的暖阳◎ 2022-05-10 03:04 444阅读 0赞

项目上有两个数据库需要切换使用jpa，查阅了网上的资料都是xml进行的配置，所以自己研究了稍加改动。  
*注：这里仅适用与1.5.x版本的spring boot 如果是2.0的请自行修改*  
1.配置数据库信息（application.properties）：

spring.datasource.url:
    spring.datasource.username:
    spring.datasource.password:
    spring.datasource.initialize=false   
    
    spring.datasource.secondary.url=
    spring.datasource.secondary.username=
    spring.datasource.secondary.password=
    spring.datasource.secondary.driverClassName=com.mysql.jdbc.Driver
    spring.datasource.driverClassName:com.mysql.jdbc.Driver
    spring.jpa.database-platform:org.hibernate.dialect.MySQLDialect
    spring.datasource.maxActive:200
    spring.datasource.maxIdle:10
    spring.datasource.initialSize:10
    spring.datasource.testOnBorrow:true
    spring.datasource.validationQuery:select 1
    spring.datasource.autoReconnect:true
    spring.jpa.hibernate.ddl-auto=none
    spring.jpa.show-sql=false
    spring.aop.auto=true
    
    spring.datasource.secondary.maxActive=200
    spring.datasource.secondary.maxIdle=10
    spring.datasource.secondary.initialSize=10
    spring.datasource.secondary.testOnBorrow=true
    spring.datasource.secondary.validationQuery=select 1
    spring.datasource.secondary.autoReconnect:true
    spring.jpa.hibernate.secondary.ddl-auto=none
    spring.jpa.secondary.show-sql=false
    spring.aop.secondary.auto=true

2.创建存储数据源信息的类，并自定义实现AbstractRoutingDataSource

*存储类：*

public class DynamicDataSourceContextHolder {
        /**
         * 当使用ThreadLocal维护变量时，ThreadLocal为每个使用该变量的线程提供独立的变量副本，
         * 所以每一个线程都可以独立地改变自己的副本，而不会影响其它线程所对应的副本。
         */
        private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
        /**
         * 校验输入的数据库名称是否正确
         */
        private static List<String> dataSourceList=new ArrayList<>();
    
        /**
         * 使用setDataSourceType设置当前的
         * @param dataSourceType
         */
        public static void setDataSourceType(String dataSourceType) {
            contextHolder.set(dataSourceType);
        }
    
        public static String getDataSourceType() {
            return contextHolder.get()==null?"primaryDataSource":contextHolder.get();
        }
    
    
        public static void clearDataSourceType() {
            contextHolder.remove();
        }
    
        public static void saveDataSourceTypeName(String name){
            dataSourceList.add(name);
        }
    
        public static boolean checkDataSourceType(String name){
            return dataSourceList.contains(name);
        }
    
    
    
    
    }

3.加载数据库信息：

@Bean(name = "primaryDataSource")
        @Qualifier("primaryDataSource")
        @ConfigurationProperties(prefix = "spring.datasource")
        public DataSource primaryDataSource(){
            return DataSourceBuilder.create().build();
        }
    
        @Bean(name = "secondaryDataSource")
        @Qualifier("secondaryDataSource")
        @ConfigurationProperties(prefix = "spring.datasource.secondary")
        public DataSource secondaryDataSource(){
            return DataSourceBuilder.create().build();
        }
    
       @Bean(name="multipleDataSource")
        @Qualifier("multipleDataSource")
        @Primary
        public DataSource MultipleDataSourceToChoose(@Qualifier("primaryDataSource")DataSource dataSource,@Qualifier("secondaryDataSource")DataSource secondaryDataSource){
            DynamicDataSource dynamicDataSource=new DynamicDataSource();
            Map<Object, Object> targetDataSources=new HashMap<>();
            targetDataSources.put("primaryDataSource",dataSource);
            targetDataSources.put("secondaryDataSource",secondaryDataSource);
            dynamicDataSource.setTargetDataSources(targetDataSources);
            dynamicDataSource.setDefaultTargetDataSource(dataSource);
            DynamicDataSourceContextHolder.saveDataSourceTypeName("primaryDataSource");
            DynamicDataSourceContextHolder.saveDataSourceTypeName("secondaryDataSource");
    
            return dynamicDataSource;
        }

4.创建自定义注解并利用aop实现动态切换  
*自定义注解：*

@Documented
    @Retention(RetentionPolicy.RUNTIME)
    @Target({ElementType.METHOD})
    public @interface ChangDataSource {
    
        String name() default "primaryDataSource";
    }

*aop动态切换:*

@Aspect
    @Order(-10)//保证该AOP在@Transactional之前执行
    @Component
    public class DynamicDataSourceAspect {
    
        Logger logger= LoggerFactory.getLogger(DynamicDataSourceAspect.class);
    
       @Before(value = "@annotation(source)")
        public void changeDataSource(JoinPoint point,ChangDataSource source) throws Exception {
            String name=source.name();
            logger.info("change dataSource :"+name);
            if(!DynamicDataSourceContextHolder.checkDataSourceType(name)){
                throw new Exception("DataSource Not Exist,Please Check Your Annotation");
            }
            DynamicDataSourceContextHolder.setDataSourceType(name);
    
        }
    
        @AfterReturning(value = "@annotation(source)")
        public void restoreDataSource(JoinPoint point,ChangDataSource source) {
            //方法执行完毕之后，销毁当前数据源信息，进行垃圾回收。
            DynamicDataSourceContextHolder.clearDataSourceType();
            logger.info("clear change dataSource");
        }
    
    
    
    }