Java obtains CPU usage, memory usage, and hard disk usage.

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;

/**
* Obtain Windows System Information (CPU, memory, and file system)
*
* @ Author Libing
*
*/

Public class windowsinfoutil {
Private Static final int cputime = 500;
Private Static finals 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 ());
}

// Get memory usage
Public static string getmemery (){
Operatingsystemmxbean osmxb = (operatingsystemmxbean) managementfactory
. Getoperatingsystemmxbean ();
// Total physical memory + virtual memory
Long totalvirtualmemory = osmxb. gettotalswapspacesize ();
// Remaining physical memory
Long freephysicalmemorysize = osmxb. getfreephysicalmemorysize ();
Double compare = (double) (1-freephysicalmemorysize * 1.0
/Totalvirtualmemory) * 100;
String STR = "memory used:" + compare. intvalue () + "% ";
Return STR;
}

// Get the file system usage
Public static list <string> getdisk (){
// Operating System
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 + ": the disk has been used" + compare. intvalue () + "% ";
List. Add (STR );
}
}
Return list;
}

// Obtain the CPU usage
Public static string getcpuratioforwindows (){
Try {
String proccmd = system. getenv ("WINDIR ")
+ "// System32 // WBEM // wmic.exe
Process get caption, CommandLine, kernelmodetime, readoperationcount, threadcount, usermodetime, writeoperationcount ";
// Obtain Process Information
Long [] C0 = readcpu(runtime.getruntime(cmd.exe C (proccmd ));
Thread. Sleep (cputime );
Long [] C1 = readcpu(runtime.getruntime(cmd.exe C (proccmd ));
If (C0! = NULL & C1! = NULL ){
Long idletime = c1 [0]-C0 [0];
Long busytime = c1 [1]-C0 [1];
Return "CPU usage :"
+ Double. valueof (
Percent * (busytime) * 1.0
/(Busytime + idletime). intvalue ()
+ "% ";
} Else {
Return "CPU usage:" + 0 + "% ";
}
} Catch (exception ex ){
Ex. printstacktrace ();
Return "CPU usage:" + 0 + "% ";
}
}

// Read CPU Information
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;
}
// Field order: 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;
}

/**
* Because string. substring has a problem in Chinese Character Processing (treat a Chinese character as a byte), there is a hidden danger in the string containing Chinese characters. The following adjustments are made:
*
* @ Param SRC
* String to be truncated
* @ Param start_idx
* Start coordinate (including the coordinate)
* @ Param end_idx
* Cutoff coordinates (including the coordinates)
* @ 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;
}
}