本文共 2762 字，大约阅读时间需要 9 分钟。

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}'" };//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）		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;	}}

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