springboot 多数据源动态切换

秒速五厘米 2023-06-19 02:18 4阅读 0赞

## 环境是: springboot 2.0.3+mybatis ##

### 大致流程：   方法执行前 -> 切换数据源 -> 执行sql ###

**1.取消单数据源默认配置**

@SpringBootApplication(exclude = {
            DataSourceAutoConfiguration.class
    })
    public class PalletDemoApplication {
        public static void main(String[] args) {
            SpringApplication.run(PalletDemoApplication.class, args);
        }
    }

**2.切换数据源**

@Aspect
    @Component
    @Lazy(false)
    @Order(0) //Order设定AOP执行顺序 使之在数据库事务上先执行
    public class SwitchDataSourceAOP {
        //这里切到你的方法目录
        @Before("execution(* com.zed.palletdemo.service.*.*(..))")
        public void process(JoinPoint joinPoint) {
            String methodName=joinPoint.getSignature().getName();
            if (methodName.startsWith("get")
                    ||methodName.startsWith("count")
                    ||methodName.startsWith("find")
                    ||methodName.startsWith("list")
                    ||methodName.startsWith("select")
                    ||methodName.startsWith("check")){
                DataSourceContextHolder.setDbType("selectDataSource");
            }else {
                //切换dataSource
                DataSourceContextHolder.setDbType("updateDataSource");
            }
        }
    }

**3.上面用到了一个类:DataSourceContextHolder看他怎么写的**

@Component
    @Lazy(false)
    public class DataSourceContextHolder {
        private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();
    
        public static void setDbType(String dbType) {
            contextHolder.set(dbType);
        }
    
        public static String getDbType() {
            return contextHolder.get();
        }
    
        public static void clearDbType() {
            contextHolder.remove();
        }
    
    }

**4.配置两个数据源bean，一会切换**

@Configuration
    public class DataSourceConfig {
    
        @Bean(name = "selectDataSource")
        @ConfigurationProperties(prefix = "spring.datasource.select") // application.properteis中对应属性的前缀
        public DataSource dataSource1() {
            return DataSourceBuilder.create().build();
        }
        
        @Bean(name = "updateDataSource")
        @ConfigurationProperties(prefix = "spring.datasource.update") // application.properteis中对应属性的前缀
        public DataSource dataSource2() {
            return DataSourceBuilder.create().build();
        }
    
    }

**5.切面主要切换数据源名称，这里正式生效**

@Component
    @Primary//不知道什么用，不加报错
    public class DynamicDataSource extends AbstractRoutingDataSource {
        @Autowired
        @Qualifier("selectDataSource")
        private DataSource selectDataSource;
    
        @Autowired
        @Qualifier("updateDataSource")
        private DataSource updateDataSource;
    
        /**
         * 这个是主要的方法，返回的是生效的数据源名称
         */
        @Override
        protected Object determineCurrentLookupKey() {
            System.out.println("DataSourceContextHolder：：："+DataSourceContextHolder.getDbType());
            return DataSourceContextHolder.getDbType();
        }
    
        /**
         * 自己配的时候老是报什么没有指定target这里设置一下，默认数据源是updateDataSource
         */
        @Override
        public void afterPropertiesSet() {
            Map<Object,Object> map = new HashMap<>();
            map.put("selectDataSource",selectDataSource);
            map.put("updateDataSource",updateDataSource);
            setTargetDataSources(map);
            setDefaultTargetDataSource(updateDataSource);
            super.afterPropertiesSet();
        }
    }

**6.然后service层方法注意一下命名，就可以动态切换了。**

*  我配的两个数据源
 *      spring:
          datasource:
            select:
              jdbc-url: jdbc:mysql://127.0.0.1:3306/test1
              driver-class-name: com.mysql.jdbc.Driver
              username: root
              password: 123456
            update:
              jdbc-url: jdbc:mysql://127.0.0.1:3306/test2
              driver-class-name: com.mysql.jdbc.Driver
              username: root
              password: 123456
            type: com.alibaba.druid.pool.DruidDataSource
    
    # 问题 #
 *  之后一直报什么找不到jdbcUrl,网上说springboot1.5以后变了，坑爹  
    https://my.oschina.net/chinesedragon/blog/1647846