1 概述
前段时间摸索在Java中怎么获取系统信息包括cpu、内存、硬盘信息等，刚开始使用Java自带的包进行获取，但这样获取的内存信息不够准确并且容易出现找不到相应包等错误，所以后面使用sigar插件进行获取。下面列举出了这两种方式获取系统信息的方式及代码。
2 使用Java自带包获取系统信息
2.1 使用Java自带包获取系统信息代码如下：
2.1.1 Bytes.java
public class Bytes { public 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; } } 2.1.2 IMonitorService.java
public interface IMonitorService { public MonitorInfoBean getMonitorInfoBean() throws Exception; }
2.1.3 MonitorInfoBean.java
public class MonitorInfoBean { private long totalMemory; private long freeMemory; private long maxMemory; private String osName; private long totalMemorySize; private long freePhysicalMemorySize; private long usedMemory; private int totalThread; private double cpuRatio; public long getFreeMemory() { return freeMemory; } public void setFreeMemory(long freeMemory) { this.freeMemory = freeMemory; } public long getFreePhysicalMemorySize() { return freePhysicalMemorySize; } public void setFreePhysicalMemorySize(long freePhysicalMemorySize) { this.freePhysicalMemorySize = freePhysicalMemorySize; } public long getMaxMemory() { return maxMemory; } public void setMaxMemory(long maxMemory) { this.maxMemory = maxMemory; } public String getOsName() { return osName; } public void setOsName(String osName) { this.osName = osName; } public long getTotalMemory() { return totalMemory; } public void setTotalMemory(long totalMemory) { this.totalMemory = totalMemory; } public long getTotalMemorySize() { return totalMemorySize; } public void setTotalMemorySize(long totalMemorySize) { this.totalMemorySize = totalMemorySize; } public int getTotalThread() { return totalThread; } public void setTotalThread(int totalThread) { this.totalThread = totalThread; } public long getUsedMemory() { return usedMemory; } public void setUsedMemory(long usedMemory) { this.usedMemory = usedMemory; } public double getCpuRatio() { return cpuRatio; } public void setCpuRatio(double cpuRatio) { this.cpuRatio = cpuRatio; } } 2.1.4
import java.io.InputStreamReader;import java.io.LineNumberReader;//import sun.management.ManagementFactory; //import com.sun.management.OperatingSystemMXBean; import java.io.*; import java.lang.management.ManagementFactory; import java.util.StringTokenizer; public class MonitorServiceImpl implements IMonitorService { private static final int CPUTIME = 30; private static final int PERCENT = 100; private static final int FAULTLENGTH = 10; private static final File versionFile = new File("/proc/version"); private static String linuxVersion = null; public MonitorInfoBean getMonitorInfoBean() throws Exception { int kb = 1024; long totalMemory = Runtime.getRuntime().totalMemory() / kb; long freeMemory = Runtime.getRuntime().freeMemory() / kb; long maxMemory = Runtime.getRuntime().maxMemory() / kb; // OperatingSystemMXBean osmxb = (OperatingSystemMXBean) // ManagementFactory // .getOperatingSystemMXBean(); // String osName = System.getProperty("os.name"); // long totalMemorySize = osmxb.getTotalPhysicalMemorySize() / kb; // long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize() / kb; // long usedMemory = (osmxb.getTotalPhysicalMemorySize() - osmxb // .getFreePhysicalMemorySize()) / kb; 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(); // } MonitorInfoBean infoBean = new MonitorInfoBean(); infoBean.setFreeMemory(freeMemory); // infoBean.setFreePhysicalMemorySize(freePhysicalMemorySize); infoBean.setMaxMemory(maxMemory); // infoBean.setOsName(osName); infoBean.setTotalMemory(totalMemory); // infoBean.setTotalMemorySize(totalMemorySize); infoBean.setTotalThread(totalThread); // infoBean.setUsedMemory(usedMemory); 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()); } } private double getCpuRatioForWindows() { try { String procCmd = System.getenv("windir") + "\\system32\\wbem\\wmic.exe process get Caption,CommandLine," + "KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount"; 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; } } 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;