package keshe;
/*自从Java 1.5,java.net包中就实现了ICMP ping的功能。
public class Ping3 {
public static boolean ping(String ipAddress) throws Exception {
int timeOut = 3000; // 超时应该在3钞以上
boolean status = InetAddress.getByName(ipAddress).isReachable(timeOut);
// 当返回值是true时,说明host是可用的,false则不可。
return status;
}
public static void ping02(String ipAddress) throws Exception {
String line = null;
try {
Process pro = Runtime.getRuntime().exec("ping " + ipAddress);
BufferedReader buf = new BufferedReader(new InputStreamReader(
pro.getInputStream()));
while ((line = buf.readLine()) != null)
System.out.println(line);
} catch (Exception ex) {
System.out.println(ex.getMessage());
}
}
public static boolean ping(String ipAddress, int pingTimes, int timeOut) {
BufferedReader in = null;
Runtime r = Runtime.getRuntime(); // 将要执行的ping命令,此命令是windows格式的命令
String pingCommand = "ping " + ipAddress + " -n " + pingTimes + " -w "
+ timeOut;
try { // 执行命令并获取输出
System.out.println(pingCommand);
Process p = r.exec(pingCommand);
if (p == null) {
return false;
}
in = new BufferedReader(new InputStreamReader(p.getInputStream())); // 逐行检查输出,计算类似出现=23ms
// TTL=62字样的次数
int connectedCount = 0;
String line = null;
while ((line = in.readLine()) != null) {
connectedCount += getCheckResult(line);
} // 如果出现类似=23ms TTL=62这样的字样,出现的次数=测试次数则返回真
return connectedCount == pingTimes;
} catch (Exception ex) {
ex.printStackTrace(); // 出现异常则返回假
return false;
} finally {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
// 若line含有=18ms TTL=16字样,说明已经ping通,返回1,否則返回0.
private static int getCheckResult(String line) { // System.out.println("控制台输出的结果为:"+line);
Pattern pattern = Pattern.compile("(\\d+ms)(\\s+)(TTL=\\d+)",
Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(line);
while (matcher.find()) {
return 1;
}
return 0;
}
public static void main(String[] args) throws Exception {
String ipAddress = "127.0.0.1";
System.out.println(ping(ipAddress));
ping02(ipAddress);
System.out.println(ping(ipAddress, 5, 5000));
}
}
这些代码的本质其实就是调用操作系统的命令行的ping命令,并且获取命令的输出结果,对结果解析,然后再显示给用户。也就是这代码本身其实就是一个调用命令行得到输出的程序,而实际的功能是ping这个命令实现的。
使用第一种方法无论能不能ping通返回都是true