Java注解如何基于Redission实现分布式锁

这篇文章主要介绍了java注解如何基于redission实现分布式锁,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

1、定义注解类

@target({ elementtype.method })
@retention(retentionpolicy.runtime)
@documented
public @interface distributedlock {
  //锁名称
  string lockname() default "";

  //释放时间
  long releasetime() default 5*1000;

  //时间单位
  timeunit timeunit() default timeunit.milliseconds;
}

2、定义切面拦截 distributedlock 注解

@aspect
@component
@slf4j
public class distributedlockaspect {

  @autowired
  private redissonclient redissonclient;
　　 //这里需要修改对应的包名
  @pointcut("@annotation(com.utils.annotation.distributedlock)")
  public void rlockaspect() {
  }

  @around("rlockaspect()")
  public object arround(proceedingjoinpoint proceedingjoinpoint) throws throwable {
    object object = null;
    rlock lock = null;

    log.info("rlockaspect start ");

    try {
      distributedlock rlockinfo = getrlockinfo(proceedingjoinpoint);
      string lockkey = getlocalkey(proceedingjoinpoint, rlockinfo);
      lock = redissonclient.getlock(lockkey);

      if (lock != null) {
        final boolean status = lock.trylock(rlockinfo.releasetime(), rlockinfo.timeunit());
        if (status) {
          object = proceedingjoinpoint.proceed();
        }
      } else {
        log.info("未获取到锁：{}", lockkey);
      }
    } finally {
      // 当前线程获取到锁再释放锁
      if (lock != null && lock.isheldbycurrentthread()) {
        lock.unlock();
      }
    }
    return object;
  }

  public distributedlock getrlockinfo(proceedingjoinpoint proceedingjoinpoint) {
    methodsignature methodsignature = (methodsignature) proceedingjoinpoint.getsignature();
    return methodsignature.getmethod().getannotation(distributedlock.class);
  }

  /**
   * 获取redis lock key
   *
   * @param proceedingjoinpoint
   * @return
   */
  public string getlocalkey(proceedingjoinpoint proceedingjoinpoint, distributedlock rlockinfo) {
    stringbuilder localkey = new stringbuilder("rlock");
    final object[] args = proceedingjoinpoint.getargs();
    string businessno = "";

    // 如果没有设置锁值
    if (stringutils.isnotempty(rlockinfo.lockname())) {
      businessno = rlockinfo.lockname();
    } else {
      methodsignature methodsignature = (methodsignature) proceedingjoinpoint.getsignature();
      class[] parameters = methodsignature.getparametertypes();
      string methodname = methodsignature.getmethod().getname();

      if (parameters != null) {
        for (int i = 0; i < parameters.length; i++) {
          class parameter = parameters[i];
          if (parameter.getsimplename().equals("ndevice")) {
            ndevice de = (ndevice) args[i];
            businessno = de.getuuid() + methodname;
          }
          if (parameter.getsimplename().equals("framebean")) {
            framebean de = (framebean) args[i];
            businessno = de.getcolumn1() + methodname;
          }
        }
        // 如果没有获取到业务编号，则使用方法签名
        if (stringutils.isempty(businessno)) {
          businessno = methodname;
        }
      }
    }
    return businessno;
  }
}

3、使用方法：在需要用分布式锁的方法上面加 @distributedlock 注解即可

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