有没有办法采取一个可调用方法的参数? [英] Is there a way to take an argument in a callable method?
问题描述
我已经创造了一项code的这需要一个IP地址(主要方法另一个类),然后通过一个IP地址范围的循环侦测每个人自有其道理。我有一个GUI前端就这个问题和它崩溃(所以为什么我已经做了多线程。我的问题是我不能再取IP地址在我的平code作为其可调用的参数。我有找遍了,这和不能似乎找到一种方法来避开这个,有没有一种方式,可调用的方法来接受参数吗?如果不是有没有其他的方式来完成我想要做什么?
I have created a piece of code which takes an IP address (from main method in another class) and then loops through a range of IP addresses pinging each one as it goes. I have a GUI front end on this and it was crashing (hence why I've done the multithreading. My problem is I can no longer take the IP address as an argument in my ping code as its callable. I've searched all over for this and cant seem to find a way to get round this. Is there a way for a callable method to take arguments? If not is there any other way to accomplish what I'm trying to do?
我的code的样本:
public class doPing implements Callable<String>{
public String call() throws Exception{
String pingOutput = null;
//gets IP address and places into new IP object
InetAddress IPAddress = InetAddress.getByName(IPtoPing);
//finds if IP is reachable or not. a timeout timer of 3000 milliseconds is set.
//Results can vary depending on permissions so cmd method of doing this has also been added as backup
boolean reachable = IPAddress.isReachable(1400);
if (reachable){
pingOutput = IPtoPing + " is reachable.\n";
}else{
//runs ping command once on the IP address in CMD
Process ping = Runtime.getRuntime().exec("ping " + IPtoPing + " -n 1 -w 300");
//reads input from command line
BufferedReader in = new BufferedReader(new InputStreamReader(ping.getInputStream()));
String line;
int lineCount = 0;
while ((line = in.readLine()) != null) {
//increase line count to find part of command prompt output that we want
lineCount++;
//when line count is 3 print result
if (lineCount == 3){
pingOutput = "Ping to " + IPtoPing + ": " + line + "\n";
}
}
}
return pingOutput;
}
}
IPtoPing曾经是拍摄参数。
IPtoPing used to be the argument that was taken.
推荐答案
您不能将它作为参数传递给()调用
由于该方法签名不允许它。
You can't pass it as the argument to call()
because the method signature doesn't allow it.
不过,你可以把它作为一个构造函数参数;例如。
However, you can pass it as a constructor argument; e.g.
public class DoPing implements Callable<String>{
private final String ipToPing;
public DoPing(String ipToPing) {
this.ipToPing = ipToPing;
}
public String call() throws Exception {
InetAddress ipAddress = InetAddress.getByName(ipToPing);
....
}
}
(我已经纠正了一个令人震惊的夫妇code风格的侵犯!)
(I've corrected a couple of egregious code style violations!!)
另外,你可以:
-
宣布兴奋剂作为一个内部类,并把它指的是
最后ipToPing
在封闭的范围内,或
添加一个 setIpToPing(字符串ipToPing)
方法。
(最后允许掺杂
对象被重用,但缺点是,你将需要同步线程安全的访问。)
(The last allows a DoPing
object to be reused, but the downside is that you will need to synchronize to access it thread-safely.)
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