java获取cpu使用率/内存使用率/硬盘的使用率

import java.io.File;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.lang.management.ManagementFactory;
import java.util.ArrayList;
import java.util.List;

import com.sun.management.OperatingSystemMXBean;

/**
* 获取windows系统信息（CPU,内存,文件系统）
*
* @author libing
*
*/

public class WindowsInfoUtil {
private static final int CPUTIME = 500;
private static final int PERCENT = 100;
private static final int FAULTLENGTH = 10;

public static void main(String[] args) {
System.out.println(getCpuRatioForWindows());
System.out.println(getMemery());
System.out.println(getDisk());
}

// 获取内存使用率
public static String getMemery() {
OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory
.getOperatingSystemMXBean();
// 总的物理内存+虚拟内存
long totalvirtualMemory = osmxb.getTotalSwapSpaceSize();
// 剩余的物理内存
long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize();
Double compare = (Double) (1 - freePhysicalMemorySize * 1.0
/ totalvirtualMemory) * 100;
String str = "内存已使用:" + compare.intValue() + "%";
return str;
}

// 获取文件系统使用率
public static List<String> getDisk() {
// 操作系统
List<String> list = new ArrayList<String>();
for (char c = 'A'; c <= 'Z'; c++) {
String dirName = c + ":/";
File win = new File(dirName);
if (win.exists()) {
long total = (long) win.getTotalSpace();
long free = (long) win.getFreeSpace();
Double compare = (Double) (1 - free * 1.0 / total) * 100;
String str = c + ":盘 已使用 " + compare.intValue() + "%";
list.add(str);
}
}
return list;
}

// 获得cpu使用率
public static String 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 "CPU使用率:"
+ Double.valueOf(
PERCENT * (busytime) * 1.0
/ (busytime + idletime)).intValue()
+ "%";
} else {
return "CPU使用率:" + 0 + "%";
}
} catch (Exception ex) {
ex.printStackTrace();
return "CPU使用率:" + 0 + "%";
}
}

// 读取cpu相关信息
private static 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 = substring(line, capidx, cmdidx - 1).trim();
String cmd = substring(line, cmdidx, kmtidx - 1).trim();
if (cmd.indexOf("wmic.exe") >= 0) {
continue;
}
String s1 = substring(line, kmtidx, rocidx - 1).trim();
String s2 = 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;
}

/**
* 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
*/
private 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;
}
}