java获取linux服务的系统信息（cpu使用率、内存使用率、系统负载）

小咪咪 2022-12-18 11:56 341阅读 0赞

### 文章目录 ###

*  1 代码
 *   *  1.1 工具类
     *  1.2 辅助bean
 *  2 问题
 *   *  2.1 java使用Runtime.exec执行linux命令不成功问题
     *   *  2.1.1 问题说明
         *  2.1.2 问题原因
         *  2.1.3 解决方案

# 1 代码 #

## 1.1 工具类 ##

说明：

*  cpu使用率，可以采用jdk工具类的方法，但是有博客说不太准确，这里不采用，通过/proc/stat方式实现。
 *  内存使用率，采用jdk工具类的方法实现。
 *  系统负载，采用uptime命令通过计算来实现。

import com.sun.management.OperatingSystemMXBean;
    import lombok.extern.slf4j.Slf4j;
    
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.InputStreamReader;
    import java.lang.management.ManagementFactory;
    import java.math.BigDecimal;
    import java.util.StringTokenizer;
    
    @Slf4j
    public class LinuxInfoUtil {
        private static final String CPU_FILE = "/proc/stat";
        private static final String LOAD_COMMAND = "uptime";
    
        /**
         * 获得Linux cpu使用率 pcpu =100* (total-idle)/total
         * total = total2-total1
         * idle = idle2 -idle1
         * total1 = user1+nice1+system1+idle1+iowait1+irq1+softirq1+stealstolen1+guest1+guest_nice1
         */
        public static BigDecimal getCpuInfo() {
            try {
                File file = new File(CPU_FILE);
                BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
                StringTokenizer procStatFirstLine = new StringTokenizer(br.readLine());
                CpuInfoBean cpuInfoBean1 = new CpuInfoBean(procStatFirstLine);
                BigDecimal total1 = cpuInfoBean1.getCpuTotal();
                Thread.sleep(1000);
                br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
                procStatFirstLine = new StringTokenizer(br.readLine());
                CpuInfoBean cpuInfoBean2 = new CpuInfoBean(procStatFirstLine);
                BigDecimal total2 = cpuInfoBean2.getCpuTotal();
                BigDecimal total = total2.subtract(total1);
                BigDecimal idle = cpuInfoBean2.getIdle().subtract(cpuInfoBean1.getIdle());
                BigDecimal pcpu = new BigDecimal(100).multiply(total.subtract(idle)).divide(total, 0, BigDecimal.ROUND_HALF_UP);
                br.close();
                return pcpu;
            } catch (Exception e) {
                log.info(e.toString());
                return new BigDecimal(0);
            }
    
        }
    
        // 获取内存使用率
        public static BigDecimal getMemory() {
            OperatingSystemMXBean osmxb = (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
            BigDecimal total = new BigDecimal(osmxb.getTotalPhysicalMemorySize());
            BigDecimal free = new BigDecimal(osmxb.getFreePhysicalMemorySize());
            BigDecimal pmem = new BigDecimal(100).multiply(total.subtract(free)).divide(total, 0, BigDecimal.ROUND_HALF_UP);
            return pmem;
        }
    
        /**
         * 获取系统负载:top的15分钟平均值/(逻辑cpu核数*0.7)
         */
        public static BigDecimal getLoad() {
            try {
                Runtime r = Runtime.getRuntime();
                BigDecimal cpuPerformance = new BigDecimal(0.7).multiply(new BigDecimal(r.availableProcessors()));
                Process pro = r.exec(LOAD_COMMAND);
                BufferedReader br = new BufferedReader(new InputStreamReader(pro.getInputStream()));
                String topLoad = br.readLine();
                BigDecimal load = new BigDecimal(topLoad.substring(topLoad.lastIndexOf(" ")+1));
                BigDecimal pload = new BigDecimal(100).multiply(load).divide(cpuPerformance, 0, BigDecimal.ROUND_HALF_UP);
                br.close();
                pro.destroy();
                return pload;
            } catch (Exception e) {
                log.info(e.toString());
                return new BigDecimal(0);
            }
        }
    }

## 1.2 辅助bean ##

*  构造方法写的有点啰嗦，博友如有更好的方式欢迎留言

import lombok.Data;
    
    import java.math.BigDecimal;
    import java.util.StringTokenizer;
    
    @Data
    public class CpuInfoBean {
        // /proc/stat中cpu数据10元组
        private BigDecimal user, nice, system, idle, iowait, irq, softirq, stealstolen, guest, guest_nice;
    
        public CpuInfoBean(StringTokenizer procStatFirstLine) {
            procStatFirstLine.nextToken();
            this.user = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.nice = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.system = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.idle = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.iowait = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.irq = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.softirq = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.stealstolen = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.guest = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
            this.guest_nice = procStatFirstLine.hasMoreTokens() ? new BigDecimal(procStatFirstLine.nextToken()) : BigDecimal.ZERO;
        }
    
        public BigDecimal getCpuTotal() {
            return user.add(nice).add(system).add(idle).add(iowait).add(irq).add(softirq).add(stealstolen).add(guest).add(guest_nice);
        }
    }

# 2 问题 #

## 2.1 java使用Runtime.exec执行linux命令不成功问题 ##

### 2.1.1 问题说明 ###

获取cpu逻辑核数失败，命令为“cat /proc/cpuinfo | grep processor | wc -l”

### 2.1.2 问题原因 ###

*  可能因为管道符“|”导致命令失败，具体不知，如有知道的博友欢迎留言回复。
 *  博友回复：直接用exec执行，会导致该命令作为一个进程执行，无法查询结果。但是通过sh -c的方式以后，该命令通过管道符分解为3个子进程，分别执行"cat /proc/cpuinfo"、“grep processor”、“wc -l”，前面进程的结果通过管道作为下一个进程的输入，从而查询到了具体的结果。

### 2.1.3 解决方案 ###

解决方式一（采用，有局限性）：
        用java自带工具实现Runtime.getRuntime().availableProcessors()
    解决方式二：
        命令参数改为数组
        String[] command = {"sh", "-c", "cat /proc/cpuinfo | grep processor | wc -l"};
        或 String[] command = { "/bin/sh", "-c", "cat /proc/cpuinfo | grep processor | wc -l"};