最近做個項目，就是要取得cpu占有率等等的系統信息，一開始以為要用動態鏈接庫了，但后來發現可以像下面這樣做，不去調用jni，這樣省去了很多看新技術的時間o(∩_∩)o...
在Java中，可以獲得總的物理內存、剩余的物理內存、已使用的物理內存等信息，下面例子可以取得這些信息，并且獲得在Windows下的內存使用率。
首先編寫一個MonitorInfoBean類，用來裝載監控的一些信息，包括物理內存、剩余的物理內存、已使用的物理內存、內存使用率等字段，該類的代碼如下：
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package com.amgkaka.performance; /** */ /** * 監視信息的JavaBean類. * @author amg * @version 1.0 * Creation date: 2008-4-25 - 上午10:37:00 */public class MonitorInfoBean { /** */ /** 可使用內存. */ private long totalMemory; /** */ /** 剩余內存. */ private long freeMemory; /** */ /** 最大可使用內存. */ private long maxMemory; /** */ /** 操作系統. */ private String osName; /** */ /** 總的物理內存. */ private long totalMemorySize; /** */ /** 剩余的物理內存. */ private long freePhysicalMemorySize; /** */ /** 已使用的物理內存. */ private long usedMemory; /** */ /** 線程總數. */ private int totalThread; /** */ /** cpu使用率. */ 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; } } |
接著編寫一個獲得當前的監控信息的接口，該類的代碼如下所示：
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package com.amgkaka.performance; /** */ /** * 獲取系統信息的業務邏輯類接口. * @author amg * @version 1.0 * Creation date: 2008-3-11 - 上午10:06:06 */public interface IMonitorService { /** */ /** * 獲得當前的監控對象. * @return 返回構造好的監控對象 * @throws Exception * @author amgkaka * Creation date: 2008-4-25 - 上午10:45:08 */ public MonitorInfoBean getMonitorInfoBean() throws Exception; } |
該類的實現類MonitorServiceImpl如下所示：
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package com.amgkaka.performance; import java.io.InputStreamReader; import java.io.LineNumberReader; import sun.management.ManagementFactory; import com.sun.management.OperatingSystemMXBean; /** */ /** * 獲取系統信息的業務邏輯實現類. * @author amg * @version 1.0 Creation date: 2008-3-11 - 上午10:06:06 */public class MonitorServiceImpl implements IMonitorService { //可以設置長些，防止讀到運行此次系統檢查時的cpu占用率，就不準了 private static final int CPUTIME = 5000 ; private static final int PERCENT = 100 ; private static final int FAULTLENGTH = 10 ; /** */ /** * 獲得當前的監控對象. * @return 返回構造好的監控對象 * @throws Exception * @author amg * Creation date: 2008-4-25 - 上午10:45:08 */ public MonitorInfoBean getMonitorInfoBean() throws Exception { int kb = 1024 ; // 可使用內存 long totalMemory = Runtime.getRuntime().totalMemory() / kb; // 剩余內存 long freeMemory = Runtime.getRuntime().freeMemory() / kb; // 最大可使用內存 long maxMemory = Runtime.getRuntime().maxMemory() / kb; OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory .getOperatingSystemMXBean(); // 操作系統 String osName = System.getProperty("os.name" ); // 總的物理內存 long totalMemorySize = osmxb.getTotalPhysicalMemorySize() / kb; // 剩余的物理內存 long freePhysicalMemorySize = osmxb.getFreePhysicalMemorySize() / kb; // 已使用的物理內存 long usedMemory = (osmxb.getTotalPhysicalMemorySize() - osmxb .getFreePhysicalMemorySize()) / kb; // 獲得線程總數 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(); } // 構造返回對象 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; } /** */ /** * 獲得CPU使用率. * @return 返回cpu使用率 * @author amg * Creation date: 2008-4-25 - 下午06:05:11 */ private double getCpuRatioForWindows() { try { String procCmd = System.getenv("windir" ) + "\\system32\\wbem\\wmic.exe process get Caption,CommandLine," + "KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount" ; // 取進程信息 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 Double.valueOf( PERCENT * (busytime) / (busytime + idletime)) .doubleValue(); } else { return 0.0 ; } } catch (Exception ex) { ex.printStackTrace(); return 0.0 ; } } /** */ /** * 讀取CPU信息. * @param proc * @return * @author amg * Creation date: 2008-4-25 - 下午06:10:14 */ 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 ; long usertime = 0 ; while ((line = input.readLine()) != null ) { if (line.length() < wocidx) { continue ; } // 字段出現順序：Caption,CommandLine,KernelModeTime,ReadOperationCount, // ThreadCount,UserModeTime,WriteOperation String caption = Bytes.substring(line, capidx, cmdidx - 1 ) .trim(); String cmd = Bytes.substring(line, cmdidx, kmtidx - 1 ).trim(); if (cmd.indexOf( "wmic.exe" ) >= 0 ) { continue ; } // log.info("line="+line); if (caption.equals( "System Idle Process" ) || caption.equals("System" )) { idletime += Long.valueOf( Bytes.substring(line, kmtidx, rocidx - 1 ).trim()) .longValue(); idletime += Long.valueOf( Bytes.substring(line, umtidx, wocidx - 1 ).trim()) .longValue(); continue ; } kneltime += Long.valueOf( Bytes.substring(line, kmtidx, rocidx - 1 ).trim()) .longValue(); usertime += Long.valueOf( Bytes.substring(line, umtidx, wocidx - 1 ).trim()) .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 ; } /** */ /** * 測試方法. * @param args * @throws Exception * @author amg * Creation date: 2008-4-30 - 下午04:47:29 */ public static void main(String[] args) throws Exception { IMonitorService service = new MonitorServiceImpl(); MonitorInfoBean monitorInfo = service.getMonitorInfoBean(); System.out.println("cpu占有率=" + monitorInfo.getCpuRatio()); System.out.println("可使用內存=" + monitorInfo.getTotalMemory()); System.out.println("剩余內存=" + monitorInfo.getFreeMemory()); System.out.println("最大可使用內存=" + monitorInfo.getMaxMemory()); System.out.println("操作系統=" + monitorInfo.getOsName()); System.out.println("總的物理內存=" + monitorInfo.getTotalMemorySize() + "kb" ); System.out.println("剩余的物理內存=" + monitorInfo.getFreeMemory() + "kb" ); System.out.println("已使用的物理內存=" + monitorInfo.getUsedMemory() + "kb" ); System.out.println("線程總數=" + monitorInfo.getTotalThread() + "kb" ); } } |
該實現類中需要用到一個自己編寫byte的工具類，該類的代碼如下所示：
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package com.amgkaka.performance; /** */ /** * byte操作類. * @author amg * @version 1.0 * Creation date: 2008-4-30 - 下午04:57:23 */public class Bytes { /** */ /** * 由于String.subString對漢字處理存在問題（把一個漢字視為一個字節)，因此在 * 包含漢字的字符串時存在隱患，現調整如下： * @param src 要截取的字符串 * @param start_idx 開始坐標（包括該坐標) * @param end_idx 截止坐標（包括該坐標） * @return */ 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; } } |
運行下MonitorBeanImpl類，讀者將會看到當前的內存、cpu利用率等信息。
PS：得到局域網內所有主機名的方法
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import java.net.InetAddress;import java.net.UnknownHostException;public class A { static public void main(String[] args) { try { //通過主機名稱得到IP地址 InetAddress address = InetAddress.getByName("192.168.9.148"); System.out.println("192.168.9.148"+": "+address.getHostAddress());// 通過IP得到主機名稱 String ips="192.168.9.",ip; InetAddress addip; for(int i=148;i<255;i++){ ip=ips+i; addip=InetAddress.getByName(ip); System.out.println(ip+": "+addip.getHostName()); } } catch(UnknownHostException uhe) { System.err.println("Unable to find: "+"192.168.9.148"); } } } |
