1.下载依赖包。地址：http://download.csdn.net/download/rexueqingchun/10156725
2.Windows系统64位：拷贝sigar-bin\lib\sigar-amd64-winnt.dll文件到jdk安装目录bin文件夹下。
3.Linux系统64位：拷贝sigar-bin\lib\libsigar-x86-linux.so文件到系统/usr/lib64/路径下。
4.运行下面测试类：

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.LineNumberReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import org.hyperic.sigar.FileSystem;
import org.hyperic.sigar.FileSystemUsage;
import org.hyperic.sigar.Mem;
import org.hyperic.sigar.Sigar;
import org.hyperic.sigar.SigarException;

public class Test1 {

    public static void main(String[] args) {
        Sigar sigar = new Sigar();  
        //获取内存
        try {
            Mem mem = sigar.getMem();
            int memTotal = (int)Math.ceil((double)mem.getTotal() / (1024L * 1024L * 1024L));
            String memFree = String.format("%.1f", (double)mem.getFree() / (1024L * 1024L * 1024L));
            String memUser = String.format("%.0f", (memTotal-Double.parseDouble(memFree))/memTotal*100);
            System.out.println("内存总量:" + memTotal + "G");
            System.out.println("内存剩余量:" + memFree + "G");
            System.out.println("内存使用率:" + memUser + "%");
        } catch (SigarException e1) {
            e1.printStackTrace();
        }
        //获取硬盘
        Long ypTotal = 0L;
        Long ypfree = 0L;
        try {
            FileSystem fslist[] = sigar.getFileSystemList();
            for (int i = 0; i < fslist.length; i++) {  
                FileSystem fs = fslist[i];              
                FileSystemUsage usage = null;  
                usage = sigar.getFileSystemUsage(fs.getDirName());  
                switch (fs.getType()) {  
                case 0: // TYPE_UNKNOWN ：未知  
                    break;  
                case 1: // TYPE_NONE  
                    break;  
                case 2: // TYPE_LOCAL_DISK : 本地硬盘  
                    // 文件系统总大小  
                    ypTotal += usage.getTotal();
                    ypfree += usage.getFree();  
                    break;  
                case 3:// TYPE_NETWORK ：网络  
                    break;  
                case 4:// TYPE_RAM_DISK ：闪存  
                    break;  
                case 5:// TYPE_CDROM ：光驱  
                    break;  
                case 6:// TYPE_SWAP ：页面交换  
                    break;  
                }      
            }   
            int hdTotal = (int)((double)ypTotal / (1024L * 1024L));
            String hdfree = String.format("%.1f", (double)ypfree / (1024L * 1024L));
            String hdUser = String.format("%.0f", (hdTotal-Double.parseDouble(hdfree))/hdTotal*100);
            System.out.println("硬盘总量:"+hdTotal+"G");  
            System.out.println("硬盘剩余量:"+hdfree+"G");
            System.out.println("硬盘使用率:" + hdUser + "%");
        } catch (SigarException e1) {
            e1.printStackTrace();
        }  
        //获取CPU使用率(Windows)
        String wcpu = String.format("%.0f",getCpuRatioForWindows())+"%";
        System.out.println("Windows的CPU使用率:"+wcpu); 
        //获取CPU使用率(Linux)
        String lcpu = cpuUsage()+"%";
        System.out.println("Linux的CPU使用率:"+lcpu); 
    }

    //获取windows系统cpu使用率
    private static double getCpuRatioForWindows() {   
        try {   
            String procCmd = System.getenv("windir")   
                    + "//system32//wbem//wmic.exe process get Caption,CommandLine,"  
                    + "KernelModeTime,ReadOperationCount,ThreadCount,UserModeTime,WriteOperationCount";   
            // 取进程信息   
            long[] c0 = readCpu(Runtime.getRuntime().exec(procCmd));   
            Thread.sleep(500);   
            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(100 * (busytime) / (busytime + idletime)).doubleValue();   
            } else {   
                return 0.0;   
            }   
        } catch (Exception ex) {   
            ex.printStackTrace();   
            return 0.0;   
        }   
    }

    private static long[] readCpu(final Process proc) {   
        long[] retn = new long[2];   
        try {   
            proc.getOutputStream().close();   
            InputStreamReader ir = new InputStreamReader(proc.getInputStream(),"gbk");   
            LineNumberReader input = new LineNumberReader(ir);   
            String line = input.readLine();   
            if (line == null || line.length() < 10) {   
                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;   
                }   
                // 字段出现顺序：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;   
    }   

    public static class Bytes {  
        /** *//** 
         * 由于String.subString对汉字处理存在问题（把一个汉字视为一个字节)，因此在 
         * 包含汉字的字符串时存在隐患，现调整如下： 
         * @param src 要截取的字符串 
         * @param start_idx 开始坐标（包括该坐标) 
         * @param end_idx   截止坐标（包括该坐标） 
         * @return 
         * @throws UnsupportedEncodingException 
         */  
        public static String substring(String src, int start_idx, int end_idx) throws UnsupportedEncodingException{  
            byte[] b = src.getBytes();  
            String tgt = "";  
            for(int i=start_idx; i<=end_idx; i++){  
                tgt +=(char)b[i];  
            }  
            return tgt;  
        }  
    } 

    /**
     * 功能：获取Linux系统cpu使用率
     * */
    public static int cpuUsage() {
        try {
            Map<?, ?> map1 = cpuinfo();
            Thread.sleep(500);
            Map<?, ?> map2 = cpuinfo();
            if(map1.size() > 0 && map2.size() > 0){
                long user1 = Long.parseLong(map1.get("user").toString());
                long nice1 = Long.parseLong(map1.get("nice").toString());
                long system1 = Long.parseLong(map1.get("system").toString());
                long idle1 = Long.parseLong(map1.get("idle").toString());

                long user2 = Long.parseLong(map2.get("user").toString());
                long nice2 = Long.parseLong(map2.get("nice").toString());
                long system2 = Long.parseLong(map2.get("system").toString());
                long idle2 = Long.parseLong(map2.get("idle").toString());

                long total1 = user1 + system1 + nice1;
                long total2 = user2 + system2 + nice2;
                float total = total2 - total1;

                long totalIdle1 = user1 + nice1 + system1 + idle1;
                long totalIdle2 = user2 + nice2 + system2 + idle2;
                float totalidle = totalIdle2 - totalIdle1;

                float cpusage = (total / totalidle) * 100;
                return (int) cpusage;
            }

        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 功能：CPU使用信息
     * */
    public static Map<?, ?> cpuinfo() {
        InputStreamReader inputs = null;
        BufferedReader buffer = null;
        Map<String, Object> map = new HashMap<String, Object>();
        try {
            inputs = new InputStreamReader(new FileInputStream("/proc/stat"));
            buffer = new BufferedReader(inputs);
            String line = "";
            while (true) {
                line = buffer.readLine();
                if (line == null) {
                    break;
                }
                if (line.startsWith("cpu")) {
                    StringTokenizer tokenizer = new StringTokenizer(line);
                    List<String> temp = new ArrayList<String>();
                    while (tokenizer.hasMoreElements()) {
                        String value = tokenizer.nextToken();
                        temp.add(value);
                    }
                    map.put("user", temp.get(1));
                    map.put("nice", temp.get(2));
                    map.put("system", temp.get(3));
                    map.put("idle", temp.get(4));
                    map.put("iowait", temp.get(5));
                    map.put("irq", temp.get(6));
                    map.put("softirq", temp.get(7));
                    map.put("stealstolen", temp.get(8));
                    break;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if(buffer != null && inputs != null){
                    buffer.close();
                    inputs.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return map;
    }

}