这篇文章主要介绍springboot结合mysql主从来实现读写分离的方法，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
1.实现的功能
基于springboot框架，application.yml配置多个数据源，使用AOP以及AbstractRootingDataSource、ThreadLocal来实现多数据源切换，以实现读写分离。mysql的主从数据库需要进行设置数据之间的同步。
2.代码实现
application.properties中的配置
spring.datasource.druid.master.driver-class-name=com.mysql.jdbc.Driverspring.datasource.druid.master.url=jdbc:mysql://127.0.0.1:3306/node2?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true&autoReconnect=true&useSSL=falsespring.datasource.druid.master.username=rootspring.datasource.druid.master.password=123456 spring.datasource.druid.slave.driver-class-name=com.mysql.jdbc.Driverspring.datasource.druid.slave.url=jdbc:mysql://127.0.0.1:3306/node1?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true&autoReconnect=true&useSSL=falsespring.datasource.druid.slave.username=rootspring.datasource.druid.slave.password=123456写一个DataSourceConfig.java来注入两个bean
@Bean @ConfigurationProperties("spring.datasource.druid.master") public DataSource masterDataSource() { logger.info("select master data source"); return DruidDataSourceBuilder.create().build(); } @Bean @ConfigurationProperties("spring.datasource.druid.slave") public DataSource slaveDataSource() { logger.info("select slave data source"); return DruidDataSourceBuilder.create().build(); }写一个enum来标识有哪些数据源
public enum DBTypeEnum { MASTER, SLAVE;}然后写一个ThreadLocal本地线程的管理类,用于设置当前线程是那一个数据源
private static final ThreadLocal<DBTypeEnum> contextHolder = new ThreadLocal<>(); private static final ThreadLocal<DBTypeEnum> contextHolder2 = ThreadLocal.withInitial(() -> DBTypeEnum.MASTER); public static void set(DBTypeEnum dbType) { contextHolder.set(dbType); } public static DBTypeEnum get() { return contextHolder.get(); } public static void master() { set(DBTypeEnum.MASTER); logger.info("切换到master数据源"); } public static void slave() { set(DBTypeEnum.SLAVE); logger.info("切换到slave数据源"); } public static void cleanAll() { contextHolder.remove(); }然后写一个DynamicDataSource继承AbstractRootingDataSource,重写它的determineCurrentLookupKey方法。
public class DynamicDataSource extends AbstractRoutingDataSource { private Logger logger = LogManager.getLogger(DynamicDataSource.class); @Override protected Object determineCurrentLookupKey() { logger.info("此时数据源为{}", DBContextHolder.get()); return DBContextHolder.get(); }}最后写一个AOP来实现数据源切换
@Aspect@Order(1)@Componentpublic class DataSourceAop { private Logger logger = LogManager.getLogger(DataSourceAop.class); @Pointcut("(execution(* com.springboot.demo.service..*.select*(..)) " + "|| execution(* com.springboot.demo.service..*.find*(..)) " + "|| execution(* com.springboot.demo.service..*.get*(..)))") public void readPointcut() { logger.info("read only operate ,into slave db"); } @Pointcut("execution(* com.springboot.demo.service..*.insert*(..)) " + "|| execution(* com.springboot.demo.service..*.update*(..)) " + "|| execution(* com.springboot.demo.service..*.delete*(..)) ") public void writePointcut() { logger.info("read or write operate ,into master db"); } @Before("readPointcut()") public void read() { logger.info("read operate"); DBContextHolder.slave(); } @Before("writePointcut()") public void write() { logger.info("write operate"); DBContextHolder.master(); } @After("writePointcut(),readPointcut()") public void clean() { logger.info("dataSource cleanAll"); DBContextHolder.cleanAll(); }}注意：这里只是使用了偷懒的方法，对于service里面的select、get、find前缀的方法都使用从库，对于insert、update和delete方法都使用主库。
可以使用注解如下来进行优化:
@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.METHOD)public @interface DataSource { @AliasFor("dataSource") DBTypeEnum value() default DBTypeEnum.MASTER; DBTypeEnum dataSource() default DBTypeEnum.MASTER;}使用此注解来放入到service方法上，
@DataSource(DBTypeEnum.SLAVE)然后AOP方法修改为：
private static final String POINT = "execution (* com.springboot.demo.service.*.*(..))"; @Around(POINT) public Object dataSourceAround(ProceedingJoinPoint joinPoint) throws Throwable { Object[] args = joinPoint.getArgs(); Object obj; Object target = joinPoint.getTarget(); String methodName = joinPoint.getSignature().getName(); Class clazz = target.getClass(); Class<?>[] parameterTypes = ((MethodSignature) joinPoint.getSignature()).getMethod().getParameterTypes(); boolean isDynamicDataSourceMethod = false; try { Method method = clazz.getMethod(methodName, parameterTypes); DataSources currentDataSource = null; if (method != null && method.isAnnotationPresent(DataSource.class)) { isDynamicDataSourceMethod = true; currentDataSource = method.getAnnotation(DataSource.class).value(); DataSourceTypeManager.set(currentDataSource); log.info("DataSourceInterceptor Switch DataSource To {}",currentDataSource); } obj = joinPoint.proceed(args); if (isDynamicDataSourceMethod) { log.info("DataSourceInterceptor DataSource {} proceed",currentDataSource); } } finally { if (isDynamicDataSourceMethod) { DataSourceTypeManager.reset(); log.info("DataSourceInterceptor Reset DataSource To {}",DataSourceTypeManager.get()); } } return obj; }以上是“springboot结合mysql主从来实现读写分离的方法”这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注编程网行业资讯频道！
