java获得CPU使用率

java获得CPU使用率,系统内存,虚拟机内存等情况(不用JNI)

2009年10月23日星期五16:30

在Java中，可以获得总的物理内存、剩余的物理内存、已使用的物理内存等信息，下面例子可以取得这些信息，并且获得在Windows下的内存使用率。

首先编写一个MonitorInfoBean类，用来装载监控的一些信息，包括物理内存、剩余的物理内存、已使用的物理内存、内存使用率等字段，该类的代码如下：

package com.hmw.system.monitor;

public class MonitorInfoBean {

/** 可使用内存. */

private long totalMemory;

/** 剩余内存. */

private long freeMemory;

/** 最大可使用内存. */

private long maxMemory;

/** 操作系统. */

private String osName;

/** 总的物理内存. */

private long totalMemorySize;

/** 剩余的物理内存. */

private long freePhysicalMemorySize;

/** 已使用的物理内存. */

private long usedMemory;

/** 线程总数. */

private int totalThread;

/** cpu使用率. */

private double cpuRatio;

public long getFreeMemory() {

return freeMemory;

}

public void setFreeMemory(long freeMemory) {

this.freeMemory = freeMemory;

}

public long getFreePhysicalMemorySize() {

return freePhysicalMemorySize;

}

public void setFreePhysicalMemorySize(long freePhysicalMemorySize) { this.freePhysicalMemorySize = freePhysicalMemorySize;

}

public long getMaxMemory() {

return maxMemory;

}

public void setMaxMemory(long maxMemory) {

this.maxMemory = maxMemory;

}

public String getOsName() {

return osName;

}

public void setOsName(String osName) {

this.osName = osName;

}

public long getTotalMemory() {

return totalMemory;

}

public void setTotalMemory(long totalMemory) {

this.totalMemory = totalMemory;

}

public long getTotalMemorySize() {

return totalMemorySize;

}

public void setTotalMemorySize(long totalMemorySize) { this.totalMemorySize = totalMemorySize;

}

public int getTotalThread() {

return totalThread;

}

public void setTotalThread(int totalThread) {

this.totalThread = totalThread;

}

public long getUsedMemory() {

return usedMemory;

}

public void setUsedMemory(long usedMemory) {

https://www.360docs.net/doc/913598665.html,edMemory = usedMemory;

}

public double getCpuRatio() {

return cpuRatio;

}

public void setCpuRatio(double cpuRatio) {

this.cpuRatio = cpuRatio;

}

}

接着编写一个获得当前的监控信息的接口，该类的代码如下所示：package com.hmw.system.monitor;

/**

* 获取系统信息的业务逻辑类接口.

*/

public interface IMonitorService {

/**

* 获得当前的监控对象.

* @return 返回构造好的监控对象

* @throws Exception

*/

public MonitorInfoBean getMonitorInfoBean() throws Exception; }

该类的实现类MonitorServiceImpl如下所示：

package com.hmw.system.monitor;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.LineNumberReader;

import java.util.StringTokenizer;

import sun.management.ManagementFactory;

import com.sun.management.OperatingSystemMXBean;

/**

*

* 获取系统信息的业务逻辑实现类.

*

* @author GuoHuang

*/

public class MonitorServiceImpl implements IMonitorService { private static final int CPUTIME = 30;

private static final int PERCENT = 100;

private static final int FAULTLENGTH = 10;

private static String linuxVersion = null;

/**

* 获得当前的监控对象.

*

* @return 返回构造好的监控对象

* @throws Exception

* @author GuoHuang

*/

public MonitorInfoBean getMonitorInfoBean() throws Exception { int kb = 1024;

// 可使用内存

long totalMemory = Runtime.getRuntime().totalMemory() / kb; // 剩余内存

long freeMemory = Runtime.getRuntime().freeMemory() / kb;

// 最大可使用内存

long maxMemory = Runtime.getRuntime().maxMemory() / kb; OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();

// 操作系统

String osName = System.getProperty("https://www.360docs.net/doc/913598665.html,");

// 总的物理内存

long totalMemorySize = osmxb.getTotalPhysicalMemorySize() / kb;

// 剩余的物理内存

long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize() / kb;

// 已使用的物理内存

long usedMemory = (osmxb.getTotalPhysicalMemorySize() - osmxb.getFreePhysicalMemorySize()) / kb;

// 获得线程总数

ThreadGroup parentThread;

for (parentThread = Thread.currentThread().getThreadGroup(); parentThread.getParent() != null; parentThread = parentThread.getParent());

int totalThread = parentThread.activeCount();

double cpuRatio = 0;

if (osName.toLowerCase().startsWith("windows")) {

cpuRatio = this.getCpuRatioForWindows();

} else {

cpuRatio = getCpuRateForLinux();

}

// 构造返回对象

MonitorInfoBean infoBean = new MonitorInfoBean();

infoBean.setFreeMemory(freeMemory);

infoBean.setFreePhysicalMemorySize(freePhysicalMemorySize); infoBean.setMaxMemory(maxMemory);

infoBean.setOsName(osName);

infoBean.setTotalMemory(totalMemory);

infoBean.setTotalMemorySize(totalMemorySize);

infoBean.setTotalThread(totalThread);

infoBean.setUsedMemory(usedMemory);

infoBean.setCpuRatio(cpuRatio);

return infoBean;

}

private static double getCpuRateForLinux() {

InputStream is = null;

InputStreamReader isr = null;

BufferedReader brStat = null;

StringTokenizer tokenStat = null;

try {

System.out.println("Get usage rate of CUP , linux version: " + linuxVersion); Process process = Runtime.getRuntime().exec("top -b -n 1");

is = process.getInputStream();

isr = new InputStreamReader(is);

brStat = new BufferedReader(isr);

if (linuxVersion.equals("2.4")) {

brStat.readLine();

brStat.readLine();

brStat.readLine();

brStat.readLine();

tokenStat = new StringTokenizer(brStat.readLine()); tokenStat.nextToken();

tokenStat.nextToken();

String user = tokenStat.nextToken();

tokenStat.nextToken();

String system = tokenStat.nextToken();

tokenStat.nextToken();

String nice = tokenStat.nextToken();

System.out.println(user + " , " + system + " , " + nice); user = user.substring(0, user.indexOf("%"));

system = system.substring(0, system.indexOf("%")); nice = nice.substring(0, nice.indexOf("%"));

float userUsage = new Float(user).floatValue();

float systemUsage = new Float(system).floatValue(); float niceUsage = new Float(nice).floatValue();

return (userUsage + systemUsage + niceUsage) / 100; } else {

brStat.readLine();

brStat.readLine();

tokenStat = new StringTokenizer(brStat.readLine());

tokenStat.nextToken();

tokenStat.nextToken();

tokenStat.nextToken();

tokenStat.nextToken();

tokenStat.nextToken();

tokenStat.nextToken();

tokenStat.nextToken();

String cpuUsage = tokenStat.nextToken();

System.out.println("CPU idle : " + cpuUsage);

Float usage = new Float(cpuUsage.substring(0, cpuUsage.indexOf("%")));

return (1 - usage.floatValue() / 100);

}

} catch (IOException ioe) {

System.out.println(ioe.getMessage());

freeResource(is, isr, brStat);

return 1;

} finally {

freeResource(is, isr, brStat);

}

}

private static void freeResource(InputStream is, InputStreamReader isr, BufferedReader br) {

try {

if (is != null)

is.close();

if (isr != null)

isr.close();

if (br != null)

br.close();

} catch (IOException ioe) {

System.out.println(ioe.getMessage());

}

}

/**

* 获得CPU使用率.

*

* @return 返回cpu使用率

* @author GuoHuang

*/

private double getCpuRatioForWindows() {

try {

String procCmd = System.getenv("windir") + "\\system32\\wbem\\wmic.exe process get

Caption,CommandLine,KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount // 取进程信息

long[] c0 = readCpu(Runtime.getRuntime().exec(procCmd));

Thread.sleep(CPUTIME);

long[] c1 = readCpu(Runtime.getRuntime().exec(procCmd));

if (c0 != null && c1 != null) {

long idletime = c1[0] - c0[0];

long busytime = c1[1] - c0[1];

return Double.valueOf(PERCENT * (busytime) / (busytime + idletime)).doubleValue();

} else {

return 0.0;

}

} catch (Exception ex) {

ex.printStackTrace();

return 0.0;

}

}

/**

* 读取CPU信息.

* @param proc

* @return

* @author GuoHuang

*/

private long[] readCpu(final Process proc) {

long[] retn = new long[2];

try {

proc.getOutputStream().close();

InputStreamReader ir = new InputStreamReader(proc.getInputStream()); LineNumberReader input = new LineNumberReader(ir);

String line = input.readLine();

if (line == null || line.length() < FAULTLENGTH) {

return null;

}

int capidx = line.indexOf("Caption");

int cmdidx = line.indexOf("CommandLine");

int rocidx = line.indexOf("ReadOperationCount");

int umtidx = line.indexOf("UserModeTime");

int kmtidx = line.indexOf("KernelModeTime");

int wocidx = line.indexOf("WriteOperationCount");

long idletime = 0;

long kneltime = 0;

long usertime = 0;

while ((line = input.readLine()) != null) {

if (line.length() < wocidx) {

continue;

}

// 字段出现顺序：Caption,CommandLine,KernelModeTime,ReadOperationCount, // ThreadCount,UserModeTime,WriteOperation

String caption = Bytes.substring(line, capidx, cmdidx - 1).trim();

String cmd = Bytes.substring(line, cmdidx, kmtidx - 1).trim();

if (cmd.indexOf("wmic.exe") >= 0) {

continue;

}

String s1 = Bytes.substring(line, kmtidx, rocidx - 1).trim();

String s2 = Bytes.substring(line, umtidx, wocidx - 1).trim();

if (caption.equals("System Idle Process") || caption.equals("System")) {

if (s1.length() > 0)

idletime += Long.valueOf(s1).longValue();

if (s2.length() > 0)

idletime += Long.valueOf(s2).longValue();

continue;

}

if (s1.length() > 0)

kneltime += Long.valueOf(s1).longValue();

if (s2.length() > 0)

usertime += Long.valueOf(s2).longValue();

}

retn[0] = idletime;

retn[1] = kneltime + usertime; return retn;

} catch (Exception ex) {

ex.printStackTrace();

} finally {

try {

proc.getInputStream().close(); } catch (Exception e) {

e.printStackTrace();

}

}

return null;

}

/**

* 测试方法.

*

* @param args

* @throws Exception

* @author GuoHuang

*/

public static void main(String[] args) throws Exception {

IMonitorService service = new MonitorServiceImpl();

MonitorInfoBean monitorInfo = service.getMonitorInfoBean();

System.out.println("cpu占有率=" + monitorInfo.getCpuRatio());

System.out.println("可使用内存=" + monitorInfo.getTotalMemory());

System.out.println("剩余内存=" + monitorInfo.getFreeMemory());

System.out.println("最大可使用内存=" + monitorInfo.getMaxMemory());

System.out.println("操作系统=" + monitorInfo.getOsName());

System.out.println("总的物理内存=" + monitorInfo.getTotalMemorySize() + "kb");

System.out.println("剩余的物理内存=" + monitorInfo.getFreeMemory() + "kb");

System.out.println("已使用的物理内存=" + monitorInfo.getUsedMemory() + "kb");

System.out.println("线程总数=" + monitorInfo.getTotalThread() + "kb");

}

}

该实现类中需要用到一个自己编写byte的工具类，该类的代码如下所示：

package com.hmw.system.monitor;

/**

* byte操作类.

*/

public class Bytes {

/**

* 由于String.subString对汉字处理存在问题（把一个汉字视为一个字节)，因此在包含汉字的字符串时存在隐患，

现调整如下：

*

* @param src 要截取的字符串

* @param start_idx 开始坐标（包括该坐标)

* @param end_idx 截止坐标（包括该坐标）

* @return

*/

public static String substring(String src, int start_idx, int end_idx) {

byte[] b = src.getBytes();

String tgt = "";

for (int i = start_idx; i <= end_idx; i++) {

tgt += (char) b[i];

}

return tgt;

}

}

运行下MonitorBeanImpl类，读者将会看到当前的内存、cpu利用率等信息。