[英]How to run service executor from Swing worker?
我正在編寫IP掃描儀應用程序,該過程耗時很長,因此我在gui的后台使用的是服務執行程序,例如:
public static List<Future<String>> checkThisIP(String ipStart, String ipEnd) throws UnknownHostException {
final ExecutorService es = Executors.newFixedThreadPool(10);
final List<Future<String>> futures = new ArrayList<>();
String ipStringStart;
String ipStringEnd;
String targetIpString;
//my update
ipStringStart = ipStart.substring(ipStart.lastIndexOf(".") + 1, ipStart.length());
ipStringEnd = ipEnd.substring(ipEnd.lastIndexOf(".") + 1, ipEnd.length());
targetIpString = ipStart.substring(0, ipStart.lastIndexOf(".") + 1);
if (!ipStart.equals(ipEnd)) {
for (int i = Integer.parseInt(ipStringStart); i <= Integer.parseInt(ipStringEnd); i++) {
String currentIp = targetIpString + i;
futures.add(runPingScan(es, currentIp));
}
} else {
futures.add(runPingScan(es, ipStart));
}
es.shutdown();
return futures;
}
public static Future<String> runPingScan(final ExecutorService es, final String ip) {
return es.submit(new Callable<String>() {
@Override
public String call() {
String returnMe = "";
//custom ping class
Ping p = new Ping();
//send message
p.SendReply(ip);
//IsReachable returns ture or false
if(p.IsReachable()){
returnMe=ip;
}
return returnMe;
}
});
}
這是使用Jbutton執行的原始松散代碼操作:
// scan result is Future list returned from service executor
List<Future<String>> scanResult = p.checkThisIP(jFormattedTextField1.getText(), jFormattedTextField2.getText());
for (final Future<String> f : scanResult) {
try {
ip = f.get();
if (!ip.equals("")) {
arp ARP = new arp();
PortScan openPort = new PortScan();
IP ipClass = new IP();
mac = ARP.getMac(ip);
manufacturer = ARP.getOUI(mac);
ports = openPort.checkIpForPorts(ip);
hostname = ipClass.hostname(ip);
title = ipClass.htmlTitle(ip);
Object[] data = {ip, mac, manufacturer, ports, hostname, title};
tableModel.addRow(data);
}
if (jFormattedTextField1.getText().equals(jFormattedTextField2.getText()) && ip.equals("")) {
JOptionPane.showMessageDialog(null, "<html>Can not ping the address ! <br> Server might be protected by <b>WAF</b>.</html>", "Alert", HEIGHT);
}
} catch (Exception ex) {
Logger.getLogger(gui.class.getName()).log(Level.SEVERE, null, ex);
}
}
運行此代碼很好,但是當我將其附加到“ 開始掃描按鈕”時 ,GUI滯后了,我在Google上搜索並確定要使用Swing Worker 。 當我單獨使用搖擺工人時,它殺死了並發性,而當我同時使用這兩個GUI時,仍然落后。 我的問題是無論如何要使按鈕(Swing worker)調用服務執行程序來執行其他過程?
當我單獨使用搖擺工人時,它殺死了並發性,而當我同時使用這兩個GUI時,仍然落后。
這里有兩件事要做:
將ping檢查分散在多個線程上
將整個操作與事件分發線程分離
您正在使用ExecutorService
第一部分的代碼。 第二部分未在您的代碼中完成,因此EDT將阻塞,直到整個操作完成為止,這將導致GUI滯后。
您需要將以下代碼移至swing worker,后者在執行程序中運行任務:
List<Future<String>> scanResult = p.checkThisIP(jFormattedTextField1.getText(), jFormattedTextField2.getText());
for (final Future<String> f : scanResult) {
try {
[...] // this is where the thread blocks, making your ui lag if it's the EDT
Object[] data = {ip, mac, manufacturer, ports, hostname, title};
首先,移動所有將由執行者的線程池處理的阻塞代碼:
public static Future<Object[]> runPingScan(final ExecutorService es, final String ip) {
return es.submit(new Callable<Object[]>() {
@Override
public Object[] call() {
//custom ping class
Ping p = new Ping();
//send message
p.SendReply(ip);
//IsReachable returns ture or false
if(p.IsReachable()){
[...] // other blocking code
return {ip, mac, manufacturer, ports, hostname, title};
} else {
// special case, use null values or throw an exception
}
}
});
}
然后,您可以使用“ 簡單背景任務”教程代碼將整個內容與EDT分離:
SwingWorker worker = new SwingWorker<List<Object[]>, Void>() {
public List<Object[]> doInBackground() {
// -- this will run in another thread --
// submit ping checks to the executor
List<Future<Object[]>> scanResult = [...]
// get results, put them in a list, return it
List<Object[]> result = new ArrayList<>();
for(Future<Object[]> f : scanResult) {
result.add(f.get()); // blocking happens here, outside of the EDT
}
return result;
}
public void done() {
// -- this will run in the EDT --
// get() the list created above
// display the result in the gui
for(Object[] data : get()) {
tableModel.addRow(data);
}
}
};
這里不包括一些特殊情況,例如ping檢查失敗,您需要以某種方式處理它們。 調用f.get()
包裝在ExecutionException
時,將從可調用對象中引發的每個異常重新拋出。 在那些特殊情況下使用它可能是您的最佳選擇。
我已經設法通過實現swing worker解決了我的問題,后台執行的功能將為服務執行程序啟動新線程並防止延遲。
//The actionpreformed by the button
SwingWorker worker = new SwingWorker<Void, Void>() {
@Override
// All actions are done this method
protected Void doInBackground() throws Exception {
String ip = "";
String mac = "";
String manufacturer = "";
String ports = "";
String hostname = "";
String title = "";
tableModel.setRowCount(0);
PingScan p = new PingScan();
List<Future<String>> scanResult = p.checkThisIP(jFormattedTextField1.getText(), jFormattedTextField2.getText());
for (final Future<String> f : scanResult) {
try {
ip = f.get();
if (!ip.equals("")) {
arp ARP = new arp();
PortScan openPort = new PortScan();
IP ipClass = new IP();
mac = ARP.getMac(ip);
manufacturer = ARP.getOUI(mac);
ports = openPort.checkIpForPorts(ip);
hostname = ipClass.hostname(ip);
title = ipClass.htmlTitle(ip);
Object[] data = {ip, mac, manufacturer, ports, hostname, title};
tableModel.addRow(data);
}
} catch (Exception e) {
System.out.println(e.getMessage());
}
}
return null;
}
};
worker.execute();
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