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Spring Boot中自定义注解结合AOP实现主备库切换问题

2019-11-26 08:45:23
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摘要:本篇文章的场景是做调度中心和监控中心时的需求,后端使用TDDL实现分表分库,需求:实现关键业务的查询监控,当用Mybatis查询数据时需要从主库切换到备库或者直接连到备库上查询,从而减小主库的压力,在本篇文章中主要记录在Spring Boot中通过自定义注解结合AOP实现直接连接备库查询。

一.通过AOP 自定义注解实现主库到备库的切换

1.1 自定义注解

自定义注解如下代码所示

import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Retention(RetentionPolicy.RUNTIME)@Target(ElementType.METHOD)public @interface SwitchDataBase {  boolean switch2Backup() default false;}

1.2 实现方法拦截器对自定义注解处理

import java.lang.reflect.Method;import java.util.Arrays;import org.aopalliance.intercept.MethodInterceptor;import org.aopalliance.intercept.MethodInvocation;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Component;/** * 处理走备库逻辑的注解 */@Componentpublic class SwitchDataBaseInterceptor implements MethodInterceptor {  private final Logger log = LoggerFactory.getLogger(SwitchDataBaseInterceptor.class);  @Override  public Object invoke(MethodInvocation invocation) throws Throwable {    Method method = invocation.getMethod();    SwitchDataBase annotation = getAnnotation(method);    if (annotation == null) {      return invocation.proceed();    }    Object val = null;    if(!ThreadLocalMap.containsKey(GroupDataSourceRouteHelper.DATASOURCE_INDEX)) {      if (annotation.switch2Backup()) {        log.info("query back up DB, method: " + method.getName());        GroupDataSourceRouteHelper.executeByGroupDataSourceIndex(1, true);      } else {        log.info("query primary DB, method: " + method.getName());        GroupDataSourceRouteHelper.executeByGroupDataSourceIndex(0, true);      }    }    try {      val = invocation.proceed();    } catch (Exception e) {      log.info(method.getDeclaringClass().getName() + "." +          invocation.getMethod().getName() + "方法调用失败,arguments:" +          Arrays.toString(invocation.getArguments()));      throw new RuntimeException(e);    } finally {      GroupDataSourceRouteHelper.removeGroupDataSourceIndex();    }    return val;  }  /**   * 找方法上面声明的注解   */  private SwitchDataBase getAnnotation(Method method) {    if (method.isAnnotationPresent(SwitchDataBase.class)) {      return method.getAnnotation(SwitchDataBase.class);    }    return null;  }}

1.3 配置OverallQueryConfiguration

在Spring Boot中装配AOP Bean,实现扫描特定目录下的注解,实现切面变成形成通知处理。示例代码如下

import com.wdk.wms.annotation.SwitchDataBaseInterceptor;import org.springframework.aop.Advisor;import org.springframework.aop.support.DefaultPointcutAdvisor;import org.springframework.aop.support.JdkRegexpMethodPointcut;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configurationpublic class SwitchDataBaseConfiguration {  @Bean(name = "overallQueryInterceptor")  public SwitchDataBaseInterceptor overallQueryInterceptor() {    return new SwitchDataBaseInterceptor();  }  //添加aop的pointcut  @Bean(name = "jdkRegexpMethodPointcut")  public JdkRegexpMethodPointcut jdkRegexpMethodPointcut() {    JdkRegexpMethodPointcut jdkRegexpMethodPointcut = new JdkRegexpMethodPointcut();    jdkRegexpMethodPointcut.setPatterns("com.wdk.wms.mapper.*");    return jdkRegexpMethodPointcut;  }  //设置默认的aop配置对应的是原来的<aop:advisor>  @Bean  public Advisor druidAdvisor() {    DefaultPointcutAdvisor defaultPointcutAdvisor = new DefaultPointcutAdvisor();    defaultPointcutAdvisor.setPointcut(jdkRegexpMethodPointcut());    defaultPointcutAdvisor.setAdvice(overallQueryInterceptor());    return defaultPointcutAdvisor;  }}

1.4 如何使用注解从主库到备库的切换

@SwitchDataBase(switch2Backup = true)List<ConsumerNoticeMsg> listByTemplateOver3(@Param("templates") List<Integer> templates);

总结

以上所述是小编给大家介绍的Spring Boot中自定义注解结合AOP实现主备库切换,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对武林网网站的支持!
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