Linux下使用java获取cpu、内存使用率

思路如下：Linux系统中可以用top命令查看进程使用CPU和内存情况，通过Runtime类的exec()方法执行命令"top”，获取"top"的输出，从而得到CPU和内存的使用情况。

使用top命令获取系统信息：

top -b -n -1 | sed -n '3p'(使用sed命令将top输出内容中的第三行打印出来)

%Cpu(s): 6.5 us, 2.2 sy, 0.7 ni, 87.0 id, 3.5 wa, 0.0 hi, 0.1 si, 0.0 st

top -b -n 1 | sed -n '3p' | awk '{print $8}'（将第三行第八列打印出来）

87.0

获取单个进程CPU,内存的占用率

cmd脚本命令：top -b -n 1 -p $pid | sed
-n '$p'

上面的$pid，就是进程的PID

Java Runtime类

每个 Java 应用程序都有一个

Runtime

类实例，使应用程序能够与其运行的环境相连接。可以通过

getRuntime

方法获取当前运行时。

应用程序不能创建自己的 Runtime 类实例。

示例程序（针对suse平台，如果是其他Linux，可能需要稍微修改程序）

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class MySystem {

	public static float getCpuUsage() {
		float cpuUsage = 0;
		float idleUsage = 0;
		Runtime rt = Runtime.getRuntime();
		String[] cmd = { "/bin/sh", "-c",
				"top -b -n 1 | sed -n '3p' | awk '{print $5}'" };<span style="color:#ff0000;"><strong>//如果使用的命令带有空格、重定向等，必须使用命令串（字符串数组）</strong></span>
		BufferedReader in = null;
		String str = "";
		try{
		Process p = rt.exec(cmd);
		in = new BufferedReader(new InputStreamReader(p.getInputStream()));
		str = in.readLine();
		}catch(Exception e){
			
		}
		str = str.substring(0,3);
		idleUsage = Float.parseFloat(str);
		cpuUsage = 100 - idleUsage;
		cpuUsage = FormatFloat.formatFloat(cpuUsage);
		System.out.println("CpuUsage:");
		System.out.println("	"+cpuUsage);
		return cpuUsage;
	}
	
	public static void getCPUMEMByPID(){
		Runtime rt = Runtime.getRuntime();
		String[] cmd = { "/bin/sh", "-c",
				"top -b -n 1 | sed -n '3p' | awk '{print $5}'" };
		BufferedReader in = null;
		String str = "";
		try{
		Process p = rt.exec(cmd);
		in = new BufferedReader(new InputStreamReader(p.getInputStream()));
		str = in.readLine();
		}catch(Exception e){
			
		}
	}
	
	public static float getMemUsage() {
		long memUsed = 0;
		long memTotal = 0;
		float memUsage = 0;
		Runtime rt = Runtime.getRuntime();
		String[] cmd = { "/bin/sh", "-c",
				"top -b -n 1 | sed -n '4p' | awk '{print $2 \"\t\" $4}'" };
		BufferedReader in = null;
		String str = "";
		try{
			Process p = rt.exec(cmd);
			in = new BufferedReader(new InputStreamReader(p.getInputStream()));
			str = in.readLine();
		}catch(Exception e){
			
		}
		
		String[] mems = str.split("\t");
		mems[0] = mems[0].substring(0,mems[0].length()-2);
		memTotal = Long.parseLong(mems[0]);
		mems[1] = mems[1].substring(0,mems[1].length()-2);
		memUsed = Long.parseLong(mems[1]);
		memUsage = (float) memUsed / memTotal * 100;
		memUsage = FormatFloat.formatFloat(memUsage);
		System.out.println("MemUsage:");
		System.out.println("	"+memUsage);
		return memUsage;
	}

}

获取cpu、内存的使用率还有其他方法

proc文件系统（http://www.cnblogs.com/yoleung/articles/1638922.html，http://blog.csdn.net/blue_jjw/article/details/8741000）

参考文章：http://zengjz88.iteye.com/blog/1595535 http://cumtyjp.blog.163.com/blog/static/7611480820093157512732/ http://blog.csdn.net/hemingwang0902/article/details/4054709