java获取cpu的使用率_java查看CPU使用率

package testSysinfo;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.LineNumberReader;

import java.util.StringTokenizer;

public class CPU {

private static final int CPUTIME = 30;

private static final int PERCENT = 100;

private static final int FAULTLENGTH = 10;

private static String linuxVersion = null;

public double getCpuRatio() {

// 操作系统

String osName = System.getProperty("os.name");

double cpuRatio = 0;

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

cpuRatio = this.getCpuRatioForWindows();

} else {

cpuRatio = this.getCpuRateForLinux();

}

return cpuRatio;

}

/**

* 获得当前的监控对象.

*

* @return 返回构造好的监控对象

*/

public MonitorInfoBean getMonitorInfoBean() throws Exception {

// 操作系统

String osName = System.getProperty("os.name");

// 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 = this.getCpuRateForLinux();

}

// 构造返回对象

MonitorInfoBean infoBean = new MonitorInfoBean();

infoBean.setTotalThread(totalThread);

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

*/

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

*/

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;

}

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;

}

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

|| caption.equals("System")) {

idletime += Long.valueOf(

Bytes.substring(line, kmtidx, rocidx - 1).trim())

.longValue();

idletime += Long.valueOf(

Bytes.substring(line, umtidx, wocidx - 1).trim())

.longValue();

continue;

}

kneltime += Long.valueOf(

Bytes.substring(line, kmtidx, rocidx - 1).trim())

.longValue();

usertime += Long.valueOf(

Bytes.substring(line, umtidx, wocidx - 1).trim())

.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;

}

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

CPU c = new CPU();

while(true){

System.out.println("cpu占有率1=" + c.getCpuRatio());

Thread.sleep(1000*2);

}

//System.out.println("cpu占有率2=" + c.getCpuRatioForWindows());

}

}