import java.io.BufferedReader;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.StringTokenizer;

import org.apache.commons.io.FileSystemUtils;

public class OSUtils {

    /**

     * 功能：可用磁盘

     * */

    public static int disk() {

        try {

            long total = FileSystemUtils.freeSpaceKb("/home");

            double disk = (double) total / 1024 / 1024;

            return (int) disk;

        } catch (IOException e) {

            e.printStackTrace();

        }

        return 0;

    }

    /**

     * 功能：获取Linux系统cpu使用率

     * */

    public static int cpuUsage() {

        try {

            Map<?, ?> map1 = OSUtils.cpuinfo();

            Thread.sleep(5 * 1000);

            Map<?, ?> map2 = OSUtils.cpuinfo();

            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 {

                buffer.close();

                inputs.close();

            } catch (Exception e2) {

                e2.printStackTrace();

            }

        }

        return map;

    }

    /**

     * 功能：内存使用率

     * */

    public static int memoryUsage() {

        Map<String, Object> map = new HashMap<String, Object>();

        InputStreamReader inputs = null;

        BufferedReader buffer = null;

        try {

            inputs = new InputStreamReader(new FileInputStream("/proc/meminfo"));

            buffer = new BufferedReader(inputs);

            String line = "";

            while (true) {

                line = buffer.readLine();

                if (line == null)

                    break;

                int beginIndex = 0;

                int endIndex = line.indexOf(":");

                if (endIndex != -1) {

                    String key = line.substring(beginIndex, endIndex);

                    beginIndex = endIndex + 1;

                    endIndex = line.length();

                    String memory = line.substring(beginIndex, endIndex);

                    String value = memory.replace("kB", "").trim();

                    map.put(key, value);

                }

            }

            long memTotal = Long.parseLong(map.get("MemTotal").toString());

            long memFree = Long.parseLong(map.get("MemFree").toString());

            long memused = memTotal - memFree;

            long buffers = Long.parseLong(map.get("Buffers").toString());

            long cached = Long.parseLong(map.get("Cached").toString());

            double usage = (double) (memused - buffers - cached) / memTotal * 100;

            return (int) usage;

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            try {

                buffer.close();

                inputs.close();

            } catch (Exception e2) {

                e2.printStackTrace();

            }

        }

        return 0;

    }

}