檢視JVM中的線程
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ThreadGroup(線程組)
1.一個線程的集合,也可包含其他線程組
2.線程組構成一棵樹,除了初始化線程組外,每一個線程組都有一個父線程組
3.允許線程通路有關自己的線程組的資訊,但不能通路其父線程組或其他線程組的資訊
4.ThreadGroup類隻能獲得處于運作狀态的線程
常用方法:
activeCount() 傳回線程組中活動線程的估計數
activeGroupCount() 傳回線程組中活動線程組的估計數
enumerate(Thread[] list,boolean recurse) 把此線程組中所有活動線程複制到指定數組中
enumerate(ThreadGroup[] list,boolean recurse) 把此線程組中所有活動子組的引用複制到指定的數組中
enumerate(Thread[] list) 把此線程組中所有活動線程複制到指定數組中
enumerate(ThreadGroup[] list) 把此線程組中所有活動子組的引用複制到指定的數組中
getName() 傳回此線程組的名稱
getParent() 傳回此線程組的父線程組
代碼例子:
package com.xhj.thread;
import java.util.ArrayList;
import java.util.List;
public class CheckThreadJVM {
public static ThreadGroup getRootThreadGroup() {
ThreadGroup rootGroup = Thread.currentThread().getThreadGroup();
while (true) {
if (rootGroup.getParent() != null) {
rootGroup = rootGroup.getParent();
} else {
break;
}
}
return rootGroup;
}
public static List<String> getThreadsName(ThreadGroup group) {
List<String> threadList = new ArrayList<String>();
Thread[] threads = new Thread[group.activeCount()];
int count = group.enumerate(threads, false);
for (int i = 0; i < count; i++) {
threadList.add(group.getName() + "線程組: " + threads[i].getName());
}
return threadList;
}
public static List<String> getThreadGroup(ThreadGroup group) {
List<String> threadList = getThreadsName(group);
ThreadGroup[] threads = new ThreadGroup[group.activeGroupCount()];
int count = group.enumerate(threads, false);
for (int i = 0; i < count; i++) {
threadList.addAll(getThreadsName(threads[i]));
}
return threadList;
}
public static void main(String[] args) {
for (String string : getThreadGroup(getRootThreadGroup())) {
System.out.println(string);
}
}
}