[Java 获取运行中的线程] #java #线程

snippet.java

ThreadGroup group = Thread.currentThread().getThreadGroup();
ThreadGroup topGroup = group;
// 遍历线程组树，获取根线程组
while (group != null) {
  topGroup = group;
  group = group.getParent();
}
// 激活的线程数再加一倍，防止枚举时有可能刚好有动态线程生成
int slackSize = topGroup.activeCount() * 2;
Thread[] slackThreads = new Thread[slackSize];
// 获取根线程组下的所有线程，返回的actualSize便是最终的线程数
int actualSize = topGroup.enumerate(slackThreads);
Thread[] atualThreads = new Thread[actualSize];
// 复制slackThreads中有效的值到atualThreads
System.arraycopy(slackThreads, 0, atualThreads, 0, actualSize);
System.out.println("Threads size is " + atualThreads.length);
for (Thread thread : atualThreads) {
  System.out.println("Thread name : " + thread.getName());
}