java 怎么查看服务器的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+"%";          }      }
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Java code
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;     }