用JAVA去获取局域网中在线设备的需求，比如我的设备IP是192.168.1.3，我需要先判断是否在线这会你就会想到的是PING但是加上端口呢？比如我的设备IP是192.168.1.3:8080呢？根据IP加端口扫描；以下是我整理出来的解决方案：

  /**
     * @description: 获取设备在线状态
     * @param networkSegment 网段 port 端口
     * @return Map<String,Boolean>
     * @author panlupeng
     * @date 2022/3/22 16:19
     */
    public static Map<String,Boolean> getDeviceOnLineStatus(String networkSegment,int port){
    
        Map<String,Integer> map=new LinkedHashMap<>();
        Map<String,Boolean> resultMap=new HashMap();
        if(StringUtils.isEmpty(networkSegment)){
    
            try{
    
                networkSegment = InetAddress.getLocalHost().getHostAddress();
            }catch (Exception e){
    
                e.printStackTrace();
            }
        }
        int lastPoint = networkSegment.lastIndexOf('.');
        String ipHead = networkSegment.substring(0, ++lastPoint);
        for (int num = 1; num < 255; num++) {
    
            String ip = ipHead + String.valueOf(num);
            map.put(ip,port);
        }
        if(!CollectionUtils.isEmpty(map)){
    
            Iterator<Map.Entry<String, Integer>> entries = map.entrySet().iterator();
            while(entries.hasNext()){
    
                Map.Entry<String, Integer> entry = entries.next();
                boolean pingIpAndPort = pingIpAndPort(entry.getKey(),entry.getValue());
                System.out.println("IP为:"+entry.getKey()+",连接状态:"+pingIpAndPort);
                resultMap.put(entry.getKey(),pingIpAndPort);
            }
        }
        return resultMap;
    }
    
    /**
     * @description: PING IP网络
     * @param  ip
     * @return boolean
     * @author panlupeng
     * @date 2022/3/22 16:53 
     */
    public static boolean pingDeviceIp(String ip){
    
        if(StringUtils.isEmpty(ip)){
    
            return false;
        }
        if (!pingIp(ip)) {
    
            return false;
        }
        int timeOut = 3000;
        boolean reachable =false;
        try{
    
            reachable = InetAddress.getByName(ip).isReachable(timeOut);
        }catch (Exception e){
    
            e.printStackTrace();
        }
        return reachable;
    }

    /**
     * ping ip
     *
     * @param ip
     * @return
     */
    public static boolean pingIp(String ip) {
    
        if (null == ip || 0 == ip.length()) {
    
            return false;
        }
        try {
    
            InetAddress.getByName(ip);
            return true;
        } catch (IOException e) {
    
            return false;
        }
    }

    /**
     * ping ip加端口
     *
     * @param ip
     * @param port
     * @return
     */
    public static boolean pingIpAndPort(String ip, String port) {
    
        if (null == ip || 0 == ip.length() || null == port || 0 == port.length() || !isInt(port) || !isRangeInt(port, 1024, 65535)) {
    
            return false;
        }
        return pingIpAndPort(ip, Integer.parseInt(port));
    }

    /**
     * 判断是否是整数
     *
     * @param str
     * @return
     */
    public static boolean isInt(String str) {
    
        if (!isNumeric(str)) {
    
            return false;
        }
        // 该正则表达式可以匹配所有的数字 包括负数
        Pattern pattern = Pattern.compile("[0-9]+");

        Matcher isNum = pattern.matcher(str); // matcher是全匹配
        if (!isNum.matches()) {
    
            return false;
        }
        return true;
    }

    /**
     * 匹配是否包含数字
     *
     * @param str
     * @return
     */
    public static boolean isNumeric(String str) {
    
        if (null == str || 0 == str.length()) {
    
            return false;
        }
        if (str.endsWith(".")) {
    
            return false;
        }
        // 该正则表达式可以匹配所有的数字 包括负数
        Pattern pattern = Pattern.compile("-?[0-9]+\\.?[0-9]*");

        Matcher isNum = pattern.matcher(str); // matcher是全匹配
        if (!isNum.matches()) {
    
            return false;
        }
        return true;
    }

    /**
     * 是否在范围内
     *
     * @param str
     * @param start
     * @param end
     * @return
     */
    public static boolean isRangeInt(String str, int start, int end) {
    
        if (!isInt(str)) {
    
            return false;
        }
        int i = Integer.parseInt(str);
        return i > start && i < end;
    }

测试结果：

用JAVA PING IP 网络解决方案如下:

    /**
     * @description: PING IP网络
     * @param  ip
     * @return boolean
     * @author panlupeng
     * @date 2022/3/22 16:53 
     */
    public static boolean pingDeviceIp(String ip){
    
        if(StringUtils.isEmpty(ip)){
    
            return false;
        }
        if (!pingIp(ip)) {
    
            return false;
        }
        int timeOut = 3000;
        boolean reachable =false;
        try{
    
            reachable = InetAddress.getByName(ip).isReachable(timeOut);
        }catch (Exception e){
    
            e.printStackTrace();
        }
        return reachable;
    }

演示结果: