SampleCode SystemStatusReader

//通过mpstat 取CPU信息的例子

import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.IOException; import java.lang.Process; import java.lang.Runtime; import java.util.HashMap;

/**

• SystemStatusReader is a collection of methods to read system status (cpu and memory)
• @author Andreu Correa Casablanca

*/

public class SystemStatusReader {

public static final int CONSERVATIVE = 0; public static final int AVERAGE = 1; public static final int OPTIMISTIC = 2;

/**

• cpuUsage gives us the percentage of cpu usage
• mpstat -P ALL out stream example:
• Linux 3.2.0-30-generic (castarco-laptop) 10/09/12 _x86_64_ (2 CPU) - To discard
• • To discard
• 00:16:30 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle - To discard
• 00:16:30 all 17,62 0,03 3,55 0,84 0,00 0,03 0,00 0,00 77,93
• 00:16:30 0 17,36 0,05 3,61 0,83 0,00 0,05 0,00 0,00 78,12
• 00:16:30 1 17,88 0,02 3,49 0,86 0,00 0,01 0,00 0,00 77,74
• @param measureMode Indicates if we want optimistic, convervative or average measurements.

*/

public static Double cpuUsage (int measureMode) throws Exception {

BufferedReader mpstatReader = null;

String mpstatLine; String[] mpstatChunkedLine;

Double selected_idle;

try {

Runtime runtime = Runtime.getRuntime(); Process mpstatProcess = runtime.exec("mpstat -P ALL");

mpstatReader = new BufferedReader(new InputStreamReader(mpstatProcess.getInputStream()));

// We discard the three first lines mpstatReader.readLine(); mpstatReader.readLine(); mpstatReader.readLine();

mpstatLine = mpstatReader.readLine(); if (mpstatLine == null) {

throw new Exception("mpstat didn't work well");

} else if (measureMode == SystemStatusReader.AVERAGE) {

mpstatChunkedLine = mpstatLine.replaceAll(",", ".").split("\s+"); selected_idle = Double.parseDouble(mpstatChunkedLine[10]);

} else {

selected_idle = (measureMode == SystemStatusReader.CONSERVATIVE)?200.:0.; Double candidate_idle;

int i = 0; while((mpstatLine = mpstatReader.readLine()) != null) {

mpstatChunkedLine = mpstatLine.replaceAll(",", ".").split("\s+"); candidate_idle = Double.parseDouble(mpstatChunkedLine[10]);

if (measureMode == SystemStatusReader.CONSERVATIVE) {

selected_idle = (selected_idle < candidate_idle)?selected_idle:candidate_idle;

} else if (measureMode == SystemStatusReader.OPTIMISTIC) {

selected_idle = (selected_idle > candidate_idle)?selected_idle:candidate_idle;

} ++i;

} if (i == 0) {

throw new Exception("mpstat didn't work well");

}

}

} catch (Exception e) {

throw e; // It's not desirable to handle the exception here

} finally {

if (mpstatReader != null) try {

mpstatReader.close();

} catch (IOException e) {

// Do nothing

}

}

return 100-selected_idle;

}

/**

• memoryUsage gives us data about memory usage (RAM and SWAP)

*/

public static HashMap<String, Integer> memoryUsage () throws Exception {

BufferedReader freeReader = null;

String freeLine; String[] freeChunkedLine;

HashMap<String, Integer> usageData = new HashMap<String, Integer>();

try {

Runtime runtime = Runtime.getRuntime(); Process freeProcess = runtime.exec("free -k"); // We measure memory in kilobytes to obtain a greater granularity

freeReader = new BufferedReader(new InputStreamReader(freeProcess.getInputStream()));

// We discard the first line freeReader.readLine();

freeLine = freeReader.readLine(); if (freeLine == null) {

throw new Exception("free didn't work well");

} freeChunkedLine = freeLine.split("\s+");

usageData.put("total", Integer.parseInt(freeChunkedLine[1]));

freeLine = freeReader.readLine(); if (freeLine == null) {

throw new Exception("free didn't work well");

} freeChunkedLine = freeLine.split("\s+");

usageData.put("used", Integer.parseInt(freeChunkedLine[2]));

freeLine = freeReader.readLine(); if (freeLine == null) {

throw new Exception("free didn't work well");

} freeChunkedLine = freeLine.split("\s+");

usageData.put("swap_total", Integer.parseInt(freeChunkedLine[1])); usageData.put("swap_used", Integer.parseInt(freeChunkedLine[2]));

} catch (Exception e) {

throw e;

} finally {

if (freeReader != null) try {

freeReader.close();

} catch (IOException e) {

// Do nothing

}

}

return usageData;

}

}