我是WatchService的新手，我有一个非常有趣的错误。当我以正常模式（运行）运行我的代码时，它将循环遍历for（Watch事件：key1.pollEvents（））循环两次并创建两个google calander事件但是如果我使用调试模式单步执行它只会添加一个事件。我从网上抓取了几乎所有的代码，试图了解WatchService的工作原理。我真的不知道我在这做什么，所以任何帮助都会很棒。这是我的代码
/*
* Copyright (c) 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.api.services.samples.calendar.cmdline;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
import static java.nio.file.StandardWatchEventKinds.OVERFLOW;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.java6.auth.oauth2.FileCredentialStore;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.DateTime;
import com.google.api.client.util.Lists;
import com.google.api.services.calendar.CalendarScopes;
import com.google.api.services.calendar.model.Calendar;
import com.google.api.services.calendar.model.Event;
import com.google.api.services.calendar.model.Event.Reminders;
import com.google.api.services.calendar.model.EventDateTime;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;
import java.util.TimeZone;
/**
* @author Yaniv Inbar
*/
public class myCalendar {
/**
* Be sure to specify the name of your application. If the application name is {@code null} or
* blank, the application will log a warning. Suggested format is "MyCompany-ProductName/1.0".
*/
private static final String APPLICATION_NAME = "";
/** Global instance of the HTTP transport. */
private static HttpTransport HTTP_TRANSPORT;
/** Global instance of the JSON factory. */
private static final JsonFactory JSON_FACTORY = new JacksonFactory();
private static com.google.api.services.calendar.Calendar client;
static final java.util.List<Calendar> addedCalendarsUsingBatch = Lists.newArrayList();
/** Authorizes the installed application to access user's protected data. */
private static Credential authorize() throws Exception {
// load client secrets
GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY,
new InputStreamReader(myCalendar.class.getResourceAsStream("/client_secrets.json")));
if (clientSecrets.getDetails().getClientId().startsWith("Enter")
|| clientSecrets.getDetails().getClientSecret().startsWith("Enter ")) {
System.out.println(
"Enter Client ID and Secret from https://code.google.com/apis/console/?api=calendar "
+ "into calendar-cmdline-sample/src/main/resources/client_secrets.json");
System.exit(1);
}
// set up file credential store
FileCredentialStore credentialStore = new FileCredentialStore(
new File(System.getProperty("user.home"), ".credentials/calendar.json"), JSON_FACTORY);
// set up authorization code flow
GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
HTTP_TRANSPORT, JSON_FACTORY, clientSecrets,
Collections.singleton(CalendarScopes.CALENDAR)).setCredentialStore(credentialStore).build();
// authorize
return new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");
}
public static void main(String[] args) throws IOException {
Path dir = Paths.get("C:\\Users\\kdevocht\\Dropbox\\Apps\\Attachments\\kjdevocht@gmail.com\\");
WatchService service = FileSystems.getDefault().newWatchService();
WatchKey key = dir.register(service, ENTRY_MODIFY);
System.out.println("Watching directory: "+dir.toString());
for(;;){
WatchKey key1;
try {
key1 = service.take();
} catch (InterruptedException x) {
break;
}
for (WatchEvent<?> event: key1.pollEvents()) {
WatchEvent.Kind<?> kind = event.kind();
if (kind == OVERFLOW) {
continue;
}
WatchEvent<Path> ev = (WatchEvent<Path>)event;
Path filename = ev.context();
Path child = dir.resolve(filename);
System.out.println("File: "+child.toString()+" modified.");
try{
try {
try {
// initialize the transport
HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
// authorization
Credential credential = authorize();
// set up global Calendar instance
client = new com.google.api.services.calendar.Calendar.Builder(
HTTP_TRANSPORT, JSON_FACTORY, credential).setApplicationName(
APPLICATION_NAME).build();
// run commands
Calendar calendar = client.calendars().get("kjdevocht@gmail.com").execute();
addEvent(calendar, child.toString());
} catch (IOException e) {
System.err.println(e.getMessage());
}
} catch (Throwable t) {
t.printStackTrace();
}
//System.exit(1);;
}catch(Exception x){
x.printStackTrace();
}
}
boolean valid = key.reset();
if (!valid) {
break;
}
/* try {
Thread.sleep(5000);
} catch(InterruptedException e) {
} */
}
我认为这可能是一个时间问题，所以我尝试了一下睡眠尝试捕获，但这不起作用。
答案 0 :(得分：0)
所以似乎一切正常。我正在使用notepad ++来编辑我正在观看的目录中的文件。经过一些研究后，似乎进行了两次修改，因此记录了两个事件。有些人建议存储文件的时间戳，只有在更改时才会做出反应，这似乎会过滤掉多个事件。对于我和我在做什么，我只是改变了观看创建活动。现在这很好用，没有任何问题