求助 如何监测java某个线程内存的占用情况啊？
public class Main { public static void main(String[] args) {
long start = Runtime.getRuntime().totalMemory();
System.out.println("start : " + start);
String s = "123123123123123";
for(int i = 0; i < 20;i ++){
s += s;
}
long end = Runtime.getRuntime().totalMemory();
System.out.println("end : " + end);
}}
这个当循环变量i很小的时候根本没有结果start = end
public class Main { public static void main(String[] args) {
long start = Runtime.getRuntime().totalMemory();
System.out.println("start : " + start);
String s = "123123123123123";
for(int i = 0; i < 20;i ++){
s += s;
}
long end = Runtime.getRuntime().totalMemory();
System.out.println("end : " + end);
}}
这个当循环变量i很小的时候根本没有结果start = end
import java.util.Vector;
import java.lang.Runnable;
import org.apache.log4j.Logger;public class ThreadPool
{
public static final int MAX_THREADS = 100; //默认最大线程数
public static final int MAX_SPARE_THREADS = 50; //默认最大空闲线程数
public static final int MIN_SPARE_THREADS = 10; //默认最小空闲线程数
public static final long MONITOR_WAIT_TIME = 60 * 1000; //每隔六十秒检查一次线程池
public static final int THREAD_MAX_ACTIVE_TIME = 5 * 60; //线程最大活动时间，缺省300秒
protected Vector m_ThreadPool; //用Vector构造的线程池
protected Vector m_BusyThreadPool; //用Vector构造的线程组，用于监控
protected MonitorRunnable m_ThreadPoolMonitor; //线程管理器
protected long m_MonitorWaitTime; //线程管理器工作间隔时间
protected int m_MaxThreads; //最大线程数
protected int m_MaxSpareThreads; //最大空闲线程数
protected int m_MinSpareThreads; //最小空闲线程数
protected int m_CurrentThreadCount; //当前线程数
protected int m_CurrentThreadsBusy; //当前忙的线程数
protected boolean m_IsStopPool; //是否关闭线程池
private int m_ThreadIDCounter=0; //线程ID号计数器
private Vector m_SpareThreadID; //用Vector构造的空闲线程ID
protected int m_ThreadMaxActiveTime;//线程最大活动时间，单位秒
protected String m_ThreadPoolName="ThreadPool";
protected Logger m_Logger; /*
* 构造函数
*/
public ThreadPool(Logger logger) {
m_Logger = logger;
m_MaxThreads = MAX_THREADS;
m_MaxSpareThreads = MAX_SPARE_THREADS;
m_MinSpareThreads = MIN_SPARE_THREADS;
m_MonitorWaitTime = MONITOR_WAIT_TIME;
m_ThreadMaxActiveTime = THREAD_MAX_ACTIVE_TIME;
m_CurrentThreadCount = 0;
m_CurrentThreadsBusy = 0;
m_IsStopPool = false;
m_BusyThreadPool = new Vector();
m_SpareThreadID = new Vector();
}
/*
* 函数功能:开启线程池
* 参数:无
* 返回:无
*/
public synchronized void start() {
//调整线程数,避免非法设置
adjustLimits();
//开启最小线程数
openThreads(m_MinSpareThreads);
//打开线程管理
m_ThreadPoolMonitor = new MonitorRunnable(this);
m_Logger.info("ThreadPool start ok");
m_Logger.info("ThreadPool MaxThreads="+m_MaxThreads+" MaxSpareThreads="+m_MaxSpareThreads+" MinSpareThreads="+m_MinSpareThreads+" MonitorWaitTime="+m_MonitorWaitTime+" ThreadMaxActiveTime="+m_ThreadMaxActiveTime);
}
public void setThreadPoolName(String threadPoolName) {
this.m_ThreadPoolName = threadPoolName;
} public String getThreadPoolName() {
return m_ThreadPoolName;
} public void setMaxThreads(int maxThreads) {
this.m_MaxThreads = maxThreads;
} public int getMaxThreads() {
return m_MaxThreads;
} public void setMinSpareThreads(int minSpareThreads) {
this.m_MinSpareThreads = minSpareThreads;
} public int getMinSpareThreads() {
return m_MinSpareThreads;
}
public void setMaxSpareThreads(int maxSpareThreads) {
this.m_MaxSpareThreads = maxSpareThreads;
}
public void setThreadMaxActiveTime(int threadMaxActiveTime) {
this.m_ThreadMaxActiveTime = threadMaxActiveTime;
} public int getMaxSpareThreads() {
return m_MaxSpareThreads;
}
public void setMonitorWaitTime(long monitorWaitTime) {
this.m_MonitorWaitTime = monitorWaitTime;
} public long getMonitorWaitTime() {
return m_MonitorWaitTime;
} public int getCurrentThreadCount() {
return m_CurrentThreadCount;
} public int getThreadMaxActiveTime() {
return m_ThreadMaxActiveTime;
}
public boolean isFullThreads(){
return m_CurrentThreadsBusy >= m_MaxThreads;
}
/*
* 函数功能:添加任务
* 参数:ThreadRunnable r
* 返回:无
*/
public void runIt(ThreadRunnable r) {
//处理异常
if (null == r) {
m_Logger.error("ThreadPool Runnable is null");
throw new NullPointerException("ThreadPool Runnable is null");
}
if (m_IsStopPool) {
m_Logger.error("ThreadPool state is illegal1: IsStopPool "+m_IsStopPool);
throw new IllegalStateException("ThreadPool state is illegal1: IsStopPool "+m_IsStopPool);
}
//声明线程
ControlRunnable c = null;
//同步
synchronized (this) {
fixThreadCount();
//当前所有线程都忙的时候
if (m_CurrentThreadsBusy == m_CurrentThreadCount) {
//如果还没有达到最大线程数,就继续增加
if (m_CurrentThreadCount < m_MaxThreads) {
int toOpen = m_CurrentThreadCount + m_MinSpareThreads;
openThreads(toOpen);
} else {
while (m_CurrentThreadsBusy == m_CurrentThreadCount) {
try {
this.wait();
}catch (InterruptedException e) {
}
if (0 == m_CurrentThreadCount || m_IsStopPool) {
m_Logger.error("ThreadPool state is illegal2: CurrentThreadCount "+m_CurrentThreadCount+" IsStopPool "+m_IsStopPool);
throw new IllegalStateException("ThreadPool state is illegal2: CurrentThreadCount "+m_CurrentThreadCount+" IsStopPool "+m_IsStopPool);
}
}
}
}
//从线程池取一条线程
c = (ControlRunnable) m_ThreadPool.lastElement();
m_ThreadPool.removeElement(c);
m_CurrentThreadsBusy++;
m_BusyThreadPool.addElement(c);
}
//执行该任务
c.runIt(r);
}
//关闭线程池
public synchronized void shutdown()
{
if (!m_IsStopPool) {
m_IsStopPool = true;
//关闭池管理
m_ThreadPoolMonitor.terminate();
m_ThreadPoolMonitor = null;
//把空闲的线程都停掉
int size = m_ThreadPool.size();
for (int i = 0; i < size; i++) {
try {
((ControlRunnable) (m_ThreadPool.elementAt(i))).terminate();
} catch (Throwable t) {
}
}
//把繁忙的线程都停掉
size = m_BusyThreadPool.size();
for (int i = 0; i < size; i++) {
try {
((ControlRunnable) (m_BusyThreadPool.elementAt(i))).terminate();
} catch (Throwable t) {
}
}
m_CurrentThreadsBusy = m_CurrentThreadCount = 0;
m_ThreadPool.clear();
m_ThreadPool = null;
m_BusyThreadPool.clear();
m_BusyThreadPool=null;
m_Logger.info("ThreadPool shutdown ok");
notifyAll();
}
}
//当空闲的线程过多的时候释放它们
protected synchronized void checkSpareControllers() {
if (m_IsStopPool) {
return;
}
m_Logger.info("ThreadPool check: CurrentCount="+m_CurrentThreadCount+" CurrentBusy="+m_CurrentThreadsBusy+" MaxSpare="+m_MaxSpareThreads);
if ((m_CurrentThreadCount - m_CurrentThreadsBusy) > m_MaxSpareThreads) {
int toFree = m_CurrentThreadCount - m_CurrentThreadsBusy - m_MaxSpareThreads;
for (int i = 0; i < toFree; i++) {
ControlRunnable c = (ControlRunnable) m_ThreadPool.firstElement();
m_ThreadPool.removeElement(c);
m_CurrentThreadCount--;
m_SpareThreadID.add(Integer.toString(c.getThreadNum()));
c.terminate();
}
}
try{
int busyNum = m_BusyThreadPool.size();
m_Logger.info("BusyThreadPool check: CurrentBusy="+busyNum);
long runtime = 0;
Vector deadThreads = new Vector();
for(int i=0; i<busyNum; i++) {
ControlRunnable c = (ControlRunnable) m_BusyThreadPool.get(i);
runtime = c.getRunTime()/1000;
m_Logger.info("BusyThreadPool check: "+c.getThreadName()+" RunTime="+runtime+"s");
if(runtime>m_ThreadMaxActiveTime) deadThreads.addElement(c);
}
//delete dead thread
int deadNum = deadThreads.size();
for(int i=0; i<deadNum; i++) {
ControlRunnable c = (ControlRunnable) deadThreads.get(i);
m_BusyThreadPool.removeElement(c);
m_CurrentThreadsBusy--;
m_CurrentThreadCount--;
c.terminate();
}
deadThreads.clear();
deadThreads=null;
}catch(Exception ex){
m_Logger.error("BusyThreadPool check error", ex);
}
try{
fixThreadCount();
}catch(Exception ex){
m_Logger.error("ThreadPool fix error", ex);
}
}
{
int spareNum = m_ThreadPool.size();
if( m_CurrentThreadsBusy != m_BusyThreadPool.size() ) {
m_CurrentThreadsBusy = m_BusyThreadPool.size();
m_Logger.info("ThreadPool fix: CurrentThreadsBusy=>"+m_CurrentThreadsBusy);
}
if( spareNum != (m_CurrentThreadCount - m_CurrentThreadsBusy)){
m_CurrentThreadCount = spareNum + m_CurrentThreadsBusy;
m_Logger.info("ThreadPool fix: CurrentThreadCount=>"+m_CurrentThreadCount);
}
}
//任务完成之后把线程放回线程池
protected synchronized void returnController(ControlRunnable c) {
if (0 == m_CurrentThreadCount || m_IsStopPool) {
c.terminate();
return;
}
m_CurrentThreadsBusy--;
m_BusyThreadPool.removeElement(c);
m_ThreadPool.addElement(c);
notify();
}
protected synchronized void notifyThreadEnd() {
m_CurrentThreadsBusy--;
m_CurrentThreadCount--;
notify();
openThreads(m_MinSpareThreads);
}
//调整线程数
protected void adjustLimits() {
if (m_MaxThreads <= 0) {
m_MaxThreads = MAX_THREADS;
}
if (m_MaxSpareThreads >= m_MaxThreads) {
m_MaxSpareThreads = m_MaxThreads;
}
if (m_MaxSpareThreads <= 0) {
if (1 == m_MaxThreads) {
m_MaxSpareThreads = 1;
} else {
m_MaxSpareThreads = m_MaxThreads / 2;
}
}
if (m_MinSpareThreads > m_MaxSpareThreads) {
m_MinSpareThreads = m_MaxSpareThreads;
}
if (m_MinSpareThreads <= 0) {
if (1 == m_MaxSpareThreads) {
m_MinSpareThreads = 1;
} else {
m_MinSpareThreads = m_MaxSpareThreads / 2;
}
}
} //开线程数
protected void openThreads(int toOpen) {
if (toOpen > m_MaxThreads) {
toOpen = m_MaxThreads;
}
if (0 == m_CurrentThreadCount) {
m_ThreadPool = new Vector(toOpen);
}
for (int i = m_CurrentThreadCount; i < toOpen; i++) {
int threadNum = 0;
if(m_SpareThreadID.size()>0){
Object num = m_SpareThreadID.firstElement();
m_SpareThreadID.remove(num);
threadNum = Integer.parseInt(num.toString());
//this.log(1, "openThreads threadNum="+threadNum);
}else{
m_ThreadIDCounter++;
threadNum = m_ThreadIDCounter;
}
m_ThreadPool.addElement(new ControlRunnable(this, threadNum));
}
m_CurrentThreadCount = toOpen;
} //记录日志
protected void log(int level, String mess) {
if(level==0) m_Logger.debug(mess);
else if(level==1) m_Logger.info(mess);
else if(level==-1) m_Logger.error(mess);
}
protected void log(String message, Throwable exception) {
m_Logger.error(message, exception);
}
//线程池管理
class MonitorRunnable implements Runnable
{
ThreadPool p;
Thread t;
boolean shouldTerminate;
long waitTimeout;
MonitorRunnable(ThreadPool p) {
shouldTerminate = false;
this.p = p;
waitTimeout = p.m_MonitorWaitTime;
t = new Thread(this, p.getThreadPoolName()+"MonitorRunnable");
t.start();
}
public void run() {
while (true) {
try {
synchronized (this) {
this.wait(waitTimeout);
}
if (shouldTerminate) {
break;
}
p.checkSpareControllers();
} catch (Throwable t) {
t.printStackTrace();
p.log("ThreadPool MonitorRunnable Throwable: "+t.getMessage(), t);
}
}
}
public synchronized void terminate() {
shouldTerminate = true;
this.notify();
}
}
//线程任务
class ControlRunnable implements Runnable {
ThreadPool m_ThreadPool;
Thread t;
ThreadRunnable toRun;
boolean shouldTerminate;
boolean shouldRun;
long startTime;
int m_ThreadNum; ControlRunnable(ThreadPool pool, int threadNum) {
toRun = null;
shouldTerminate = false;
shouldRun = false;
this.m_ThreadNum = threadNum;
this.m_ThreadPool = pool;
t = new Thread(this, m_ThreadPool.getThreadPoolName()+"Thread["+m_ThreadNum+"]");
t.setDaemon(true);
t.start();
} public void run() {
while (true) {
try {
synchronized (this) {
if (!shouldRun && !shouldTerminate) {
this.wait();
}
}
if (shouldTerminate) break;
try {
startTime = System.currentTimeMillis();
if (shouldRun) {
toRun.runIt();
if (shouldTerminate) break;
}
} catch (Throwable t) {
t.printStackTrace();
m_ThreadPool.log("ThreadPool ControlRunnable Throwable:"+t.getMessage(), t);
//System.err.println("ControlRunnable Throwable: ");
//shouldTerminate = true;
//m_ThreadPool.notifyThreadEnd();
} finally{
try{
if(toRun!=null) toRun.terminate();
}catch(Exception e){
}
toRun=null;
shouldRun = false;
m_ThreadPool.log(0, "shouldRun="+shouldRun+", shouldTerminate="+shouldTerminate);
}
if (shouldTerminate) break;
m_ThreadPool.returnController(this);
} catch (InterruptedException ie) {
}
}
} public synchronized void runIt(ThreadRunnable toRun) {
if (toRun == null) {
m_ThreadPool.log(-1, "ThreadPool ControlRunnable runIt: No Runnable");
throw new NullPointerException("ThreadPool ControlRunnable runIt: No Runnable");
}
this.toRun = toRun;
shouldRun = true;
this.notify();
}
public String getThreadName(){
return t.getName();
}
public int getThreadNum(){
return m_ThreadNum;
}
public long getRunTime(){
return (System.currentTimeMillis() - startTime);
} public void terminate() {
shouldTerminate = true;
if(toRun!=null) toRun.terminate();
//m_ThreadPool.log(1, "ThreadPool "+t.getName()+" terminate");
//this.notify();
this.destroy();
}
void destroy(){
try{
t.join(10);
if(t.isAlive()) t.interrupt();
m_ThreadPool.log(1, "ThreadPool "+t.getName()+" destroy ");
}catch(Exception e){
m_ThreadPool.log(-1, "ThreadPool "+t.getName()+" destroy error: "+e.toString());
}
}
}
}