用java取得linux系统cpu、内存的实时信息

http://blog.csdn.net/waferleo/article/details/3877806

取Linux系统下的CPU、内存信息

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.util.StringTokenizer; 

import org.apache.log4j.Logger; 

/**
 * 取得linux系统下的cpu、内存信息
 *
 *

 *
 * @author leo
 *        

 * @date 2008
 */
public final class LinuxSystemTool implements Runnable
{
    private Logger log = Logger.getLogger(LinuxSystemTool.class);
    private Config config=Config.getInstance();
    /**
      * get memory by used info
      *
      * @return int[] result
      *         result.length==4;int[0]=MemTotal;int[1]=MemFree;int[2]=SwapTotal;int[3]=SwapFree;
      * @throws IOException
      * @throws InterruptedException
      */
     public void run()
     {
         // TODO Auto-generated method stub 

         while (true) {
             try {
                 exec();
                 Thread.sleep(config.getThreadTime());
             }
             catch (Exception e) {
                 // TODO Auto-generated catch block
                 log.error("Performance Monitoring error:"+e.getMessage());
                 e.printStackTrace();
             }
         }
     }
     public void exec() throws Exception
     {
 //      ServerStatus ss = new ServerStatus(); 

         InetAddress inet = InetAddress.getLocalHost();
         System.out.println("Performance Monitoring ip:"+inet.toString()); 

         String ip=inet.toString().substring(inet.toString().indexOf("/")+1);
         log.info("Performance Monitoring ip:"+ip); 

         int[] memInfo = LinuxSystemTool.getMemInfo();
         System.out.println("MemTotal：" + memInfo[0]);
         System.out.println("MemFree：" + memInfo[1]); 

         SnmpUtil util=new SnmpUtil();
         util.setCPU(getCpuInfo());
//      util.setDISK(1);
         util.setMEM(memInfo[0]/memInfo[1]);
         util.setIP(ip); 

     }
     public static int[] getMemInfo() throws IOException, InterruptedException
    {
         File file = new File("/proc/meminfo");
         BufferedReader br = new BufferedReader(new InputStreamReader(
                 new FileInputStream(file)));
         int[] result = new int[4];
         String str = null;
         StringTokenizer token = null;
         while ((str = br.readLine()) != null) {
             token = new StringTokenizer(str);
             if (!token.hasMoreTokens())
                 continue; 

             str = token.nextToken();
             if (!token.hasMoreTokens())
                 continue; 

             if (str.equalsIgnoreCase("MemTotal:"))
                 result[0] = Integer.parseInt(token.nextToken());
             else if (str.equalsIgnoreCase("MemFree:"))
                 result[1] = Integer.parseInt(token.nextToken());
             else if (str.equalsIgnoreCase("SwapTotal:"))
                 result[2] = Integer.parseInt(token.nextToken());
             else if (str.equalsIgnoreCase("SwapFree:"))
                 result[3] = Integer.parseInt(token.nextToken());
         }
         return result;
     } 

      /**
       * get memory by used info
       *
       * @return float efficiency
       * @throws IOException
       * @throws InterruptedException
       */
      public static float getCpuInfo() throws IOException, InterruptedException
      {
         File file = new File("/proc/stat");
         BufferedReader br = new BufferedReader(new InputStreamReader(
                 new FileInputStream(file)));
         StringTokenizer token = new StringTokenizer(br.readLine());
         token.nextToken();
         int user1 = Integer.parseInt(token.nextToken());
         int nice1 = Integer.parseInt(token.nextToken());
         int sys1 = Integer.parseInt(token.nextToken());
         int idle1 = Integer.parseInt(token.nextToken()); 

         Thread.sleep(1000); 

         br = new BufferedReader(
                 new InputStreamReader(new FileInputStream(file)));
         token = new StringTokenizer(br.readLine());
         token.nextToken();
         int user2 = Integer.parseInt(token.nextToken());
         int nice2 = Integer.parseInt(token.nextToken());
         int sys2 = Integer.parseInt(token.nextToken());
         int idle2 = Integer.parseInt(token.nextToken()); 

         return (float) ((user2 + sys2 + nice2) - (user1 + sys1 + nice1))
                 / (float) ((user2 + nice2 + sys2 + idle2) - (user1 + nice1
                         + sys1 + idle1));
     } 

     /**
      * 测试类
      *
      *

      *
      * @author
      *

      * @date
      */ 

     public static void main(String[] args) throws Exception {
         int[] memInfo = LinuxSystemTool.getMemInfo();
         System.out.println("MemTotal：" + memInfo[0]);
         System.out.println("MemFree：" + memInfo[1]);
         System.out.println("SwapTotal：" + memInfo[2]);
         System.out.println("SwapFree：" + memInfo[3]); 

         System.out.println("CPU利用率：" + LinuxSystemTool.getCpuInfo());
     }
 } 

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.util.StringTokenizer;

import org.apache.log4j.Logger;

/**
 * 取得linux系统下的cpu、内存信息
 *
 *

 *
 * @author leo
 *        

 * @date 2008
 */
public final class LinuxSystemTool implements Runnable{
 private Logger log = Logger.getLogger(LinuxSystemTool.class);
 private Config config=Config.getInstance();
 /**
  * get memory by used info
  *
  * @return int[] result
  *         result.length==4;int[0]=MemTotal;int[1]=MemFree;int[2]=SwapTotal;int[3]=SwapFree;
  * @throws IOException
  * @throws InterruptedException
  */
 public void run() {
  // TODO Auto-generated method stub

  while (true) {

   try {
    exec();
    Thread.sleep(config.getThreadTime());
   } catch (Exception e) {
    // TODO Auto-generated catch block
    log.error("Performance Monitoring error:"+e.getMessage());
    e.printStackTrace();
   }
  }
 }
 public void exec() throws Exception {
//  ServerStatus ss = new ServerStatus();

  InetAddress inet = InetAddress.getLocalHost();
  System.out.println("Performance Monitoring ip:"+inet.toString());

  String ip=inet.toString().substring(inet.toString().indexOf("/")+1);
  log.info("Performance Monitoring ip:"+ip);

  int[] memInfo = LinuxSystemTool.getMemInfo();
  System.out.println("MemTotal：" + memInfo[0]);
  System.out.println("MemFree：" + memInfo[1]);

  SnmpUtil util=new SnmpUtil();
  util.setCPU(getCpuInfo());
//  util.setDISK(1);
  util.setMEM(memInfo[0]/memInfo[1]);
  util.setIP(ip);

 }
 public static int[] getMemInfo() throws IOException, InterruptedException {
  File file = new File("/proc/meminfo");
  BufferedReader br = new BufferedReader(new InputStreamReader(
    new FileInputStream(file)));
  int[] result = new int[4];
  String str = null;
  StringTokenizer token = null;
  while ((str = br.readLine()) != null) {
   token = new StringTokenizer(str);
   if (!token.hasMoreTokens())
    continue;

   str = token.nextToken();
   if (!token.hasMoreTokens())
    continue;

   if (str.equalsIgnoreCase("MemTotal:"))
    result[0] = Integer.parseInt(token.nextToken());
   else if (str.equalsIgnoreCase("MemFree:"))
    result[1] = Integer.parseInt(token.nextToken());
   else if (str.equalsIgnoreCase("SwapTotal:"))
    result[2] = Integer.parseInt(token.nextToken());
   else if (str.equalsIgnoreCase("SwapFree:"))
    result[3] = Integer.parseInt(token.nextToken());
  }

  return result;
 }

 /**
  * get memory by used info
  *
  * @return float efficiency
  * @throws IOException
  * @throws InterruptedException
  */
 public static float getCpuInfo() throws IOException, InterruptedException {
  File file = new File("/proc/stat");
  BufferedReader br = new BufferedReader(new InputStreamReader(
    new FileInputStream(file)));
  StringTokenizer token = new StringTokenizer(br.readLine());
  token.nextToken();
  int user1 = Integer.parseInt(token.nextToken());
  int nice1 = Integer.parseInt(token.nextToken());
  int sys1 = Integer.parseInt(token.nextToken());
  int idle1 = Integer.parseInt(token.nextToken());

  Thread.sleep(1000);

  br = new BufferedReader(
    new InputStreamReader(new FileInputStream(file)));
  token = new StringTokenizer(br.readLine());
  token.nextToken();
  int user2 = Integer.parseInt(token.nextToken());
  int nice2 = Integer.parseInt(token.nextToken());
  int sys2 = Integer.parseInt(token.nextToken());
  int idle2 = Integer.parseInt(token.nextToken());

  return (float) ((user2 + sys2 + nice2) - (user1 + sys1 + nice1))
    / (float) ((user2 + nice2 + sys2 + idle2) - (user1 + nice1
      + sys1 + idle1));
 }

 /**
  * 测试类
  *
  *

  *
  * @author
  *

  * @date
  */

 public static void main(String[] args) throws Exception {
  int[] memInfo = LinuxSystemTool.getMemInfo();
  System.out.println("MemTotal：" + memInfo[0]);
  System.out.println("MemFree：" + memInfo[1]);
  System.out.println("SwapTotal：" + memInfo[2]);
  System.out.println("SwapFree：" + memInfo[3]);

  System.out.println("CPU利用率：" + LinuxSystemTool.getCpuInfo());
 }
}
1、CPU
在文件”/proc/stat”里面就包含了CPU的信息。每一个CPU的每一tick用在什么地方都在这个文件里面记着。后面的数字含义分别是： user、nice、sys、idle、iowait。有些版本的kernel没有iowait这一项。这些数值表示从开机到现在，CPU的每tick用在了哪里。例如：
cpu0 256279030 0 11832528 1637168262
就是cpu0从开机到现在有 256279030 tick用在了user消耗，11832528用在了sys消耗。所以如果想计算单位时间（例如1s）里面CPU的负载，那只需要计算1秒前后数值的差除以每一秒的tick数量就可以了。gkrellm就是这样实现的：((200 * (v2 - v1) / CPU_TICKS_PER_SECOND) + 1) /2
例如，第一次读取/proc/stat，user的值是256279030；一秒以后再读一次，值是256289030，那么CPU在这一秒的 user消耗就是：((200 * (256289030 - 256279030) / CPU_TICKS_PER_SECOND) + 1) /2 = ((10000 * 200 / 1000000) + 1) / 2 = 1%了。
2、内存消耗
文件”/proc/meminfo”里面包含的就是内存的信息，还包括了swap的信息。例如：
$ cat /proc/meminfo
total: used: free: shared: buffers: cached:
Mem: 1057009664 851668992 205340672 0 67616768 367820800
Swap: 2146787328 164429824 1982357504
MemTotal: 1032236 kB
MemFree: 200528 kB
MemShared: 0 kB
……
不过从gkrellm的源代码看，有些版本没有前面那两行统计的信息，只能够根据下面的Key: Value这种各式的数据收集。
3、磁盘空间
从gkrellm的源代码看，这个是一个很复杂的数据。磁盘分区的数据有可能分布在：/proc/mounts、/proc/diskstats、 /proc/partitions等等。而且如果想要检查某几个特定的路径，还需要通过mount、df等命令的帮助。为了减少麻烦，这个数据我就直接用 statfs函数直接获得了。
int statfs(const char *path, struct statfs *buf);
这个函数只需要输入需要检查的路径名称，就可以返回这个路径所在的分区的空间使用情况：
总空间：buf.f_bsize * buf.f_blocks
空余空间：buf.f_bsize * buf.f_bavail
4、磁盘I/O
磁盘I/O的数据也同样比较复杂，有些版本看/proc/diskstats，有些版本看/proc/partitions，还有些版本至今我也不知道在那里看……不过可以看到数据的版本也像CPU那样，需要隔一段时间取值，两次取值的差就是流量。
5、网络流量
网络流量也是五花八门，不过基本上都可以在/proc/net/dev里面获得。同样也是需要两次取值取其差作为流量值。