我有一个实时程序，我需要执行一个名为“execTask（Packet task）”的方法，只需要在某个System.currentTimeMillis（）中调用它。有没有办法做到这一点？
答案 0 :(得分：2)
答案 1 :(得分：0)
查看Quartz日程安排程序。我假设你是用Java做的吗？
答案 2 :(得分：0)
比你想要的多一点，但相当普遍（一旦有人清理了特定的东西）：
EventList.java
/**
*
*/
package com.jodatosa.auction.timekeeper;
import java.util.concurrent.DelayQueue;
/**
* @author db2admin
*
*/
public class EventList {
public static final int NO_EVENT = 0;
public static final int SWITCH_ITEM_TO_POSTED = 1;
public static final int SWITCH_ITEM_TO_CLOSED = 2;
public static final int UNLOCK_REGISTERED_USER = 3;
private DelayQueue<EventObject> eventList;
public EventList() {
eventList = new DelayQueue<EventObject>();
}
public void add(int eventType, long eventTime, int id) {
eventList.put(new EventObject(eventType, eventTime, id));
}
public EventObject waitForNext() throws InterruptedException {
return eventList.take();
}
public int size() {
return eventList.size();
}
public EventObject peek() {
return eventList.peek();
}
}
EventObject.java
package com.jodatosa.auction.timekeeper;
import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;
import com.jodatosa.auction.auditing.Trace;
public class EventObject implements Delayed {
int eventType;
long eventTime;
int id;
EventObject(int eventType, long eventTime, int id) {
this.eventType = eventType;
this.eventTime = eventTime;
this.id = id;
}
public long getDelay(TimeUnit unit) {
long delay = unit.convert(eventTime - System.currentTimeMillis(), TimeUnit.MILLISECONDS);
if (unit == TimeUnit.MILLISECONDS) {
Trace.message("EventObject.getDelay time unit = MILLISECONDS");
}
else if (unit == TimeUnit.MICROSECONDS) {
Trace.message("EventObject.getDelay time unit = MICROSECONDS");
}
else if (unit == TimeUnit.NANOSECONDS) {
Trace.message("EventObject.getDelay time unit = NANOSECONDS");
}
Trace.message("EventObject.getDelay returning " + delay);
return delay;
}
public int compareTo(Delayed o) {
EventObject comparand = (EventObject) o;
if (this.eventTime < comparand.eventTime) {
return -1;
}
else if (this.eventTime > comparand.eventTime) {
return 1;
}
return 0;
}
}
Timekeeper.java
/**
*
*/
package com.jodatosa.auction.timekeeper;
import java.sql.SQLException;
import com.jodatosa.auction.auditing.Trace;
import com.jodatosa.auction.controller.AuctionControl;
import com.jodatosa.auction.datastore.jdbc.TableConnection;
import com.jodatosa.auction.model.Item;
import com.jodatosa.auction.model.User;
import com.jodatosa.auction.util.AuctionProperties;
/**
* @author db2admin
*
*/
public class Timekeeper {
private static EventList eventList;
public Timekeeper() {
// TODO
}
public static void initializeEventList() throws SQLException {
eventList = new EventList();
long currentTime = System.currentTimeMillis();
// Scan Users for locked Users and extract the time locked
User user = User.findByStatus(User.ACCOUNT_DISABLED_FOR_LOGIN);
if (user != null) {
long currentTimePlus2 = System.currentTimeMillis() - AuctionProperties.getTimeForLockedUserToUnlock();
do {
// Compare time locked + 2 days to current time
if (user.getTime_locked_for_failed_logins() < currentTimePlus2) {
Trace.message("Timekeeper.initializeEventList: Unlocking user " + user.getUser_name() + ", locked at time " + user.getTime_locked_for_failed_logins());
// Immediately unlock those where time has expired.
AuctionControl.unlockRegisteredUser(user.getUser_id());
}
else {
// For those not expired, enter an event into the event list.
int eventType = EventList.UNLOCK_REGISTERED_USER;
long eventTime = user.getTime_locked_for_failed_logins() + AuctionProperties.getTimeForLockedUserToUnlock();
int userId = user.getUser_id();
Trace.message("Timekeeper.initializeEventList: Adding event type " + eventType + " for user " + user.getUser_name() + " at time " + eventTime);
eventList.add(eventType, eventTime, userId);
}
} while (user.next());
}
// Scan Items. Extract item status, time to post, and time to close.
// For items not yet posted, check time to post and either set status to posted or add to event list.
// For posted items not yet closed, check time to close and process similarly.
Item item = Item.getAll();
if (item != null) {
boolean more = true;
do {
int itemId = item.getItem_id();
int status = item.getStatus();
Trace.message("Timekeeper.initializeEventList: Examining item #" + itemId + " with status " + status);
int oldStatus = status;
long eventTime = 0;
int eventType = EventList.NO_EVENT;
if (status == Item.STATUS_NOT_POSTED) {
long timeToPost = item.getTime_to_post();
if (timeToPost < currentTime) {
// Switch status to posted
status = Item.STATUS_POSTED;
}
else {
// Add item to event list
eventTime = timeToPost;
eventType = EventList.SWITCH_ITEM_TO_POSTED;
}
}
if (status == Item.STATUS_POSTED) {
long timeToClose = item.getTime_to_close();
if (timeToClose < currentTime) {
// Switch status to closed
status = Item.STATUS_CLOSED;
}
else {
// Add item to event list
eventTime = timeToClose;
eventType = EventList.SWITCH_ITEM_TO_CLOSED;
}
}
// If item status changed, update item
if (status != oldStatus) {
Trace.message("Timekeeper.initializeEventList: Changing item #" + itemId + " status " + oldStatus + " to " + status);
Item updateItem = Item.getByItemIdForUpdate(itemId);
if (updateItem == null) {
Trace.error("Could not find item #" + itemId + " to update");
}
else {
updateItem.setStatus(status);
updateItem.update();
TableConnection.commit();
}
}
// If event type set, register new event to occur.
if (eventType != EventList.NO_EVENT) {
Trace.message("Timekeeper.initializeEventList: Adding event type " + eventType + " for item #" + itemId + " at time " + eventTime);
eventList.add(eventType, eventTime, itemId);
}
// Advance to next entry
more = item.next();
} while(more);
}
// TODO -- Dutch auction
}
public static Thread startTimerThread() {
TimerThread timerThread = new TimerThread(eventList);
timerThread.setName("AuctionTimerThread");
timerThread.setDaemon(true);
timerThread.start();
Trace.message("Timekeeper.startTimerThread completed");
return timerThread;
}
public static void endTimerThread(Thread timerThread) {
timerThread.interrupt();
}
public static void addAuctionStart(int auctionId, long postTime) {
eventList.add(EventList.SWITCH_ITEM_TO_POSTED, postTime, auctionId);
}
public static void addAuctionClose(int auctionId, long closeTime) {
eventList.add(EventList.SWITCH_ITEM_TO_CLOSED, closeTime, auctionId);
}
public static void addRegisteredUserLocked(int userId, long lockTime) {
eventList.add(EventList.UNLOCK_REGISTERED_USER, lockTime + AuctionProperties.getTimeForLockedUserToUnlock(), userId);
}
}
TimerThread.java
/**
*
*/
package com.jodatosa.auction.timekeeper;
import java.sql.SQLException;
import com.jodatosa.auction.auditing.Trace;
import com.jodatosa.auction.controller.AuctionControl;
/**
* @author db2admin
*
*/
public class TimerThread extends Thread implements Runnable {
private EventList eventList;
public TimerThread(EventList eventList) {
this.eventList = eventList;
}
/* (non-Javadoc)
* @see java.lang.Runnable#run()
*/
public void run() {
Trace.message("TimerThread.run starting");
try {
while(true) {
Trace.message("TimerThread.run: EventList size = " + eventList.size());
EventObject peekObject = eventList.peek();
if (peekObject == null) {
Trace.message("TimerThread.run: EventList peek = null");
}
else {
Trace.message("TimerThread.run: EventList peek = " + peekObject.eventType + ", " + peekObject.eventTime + ", " + peekObject.id);
}
EventObject eventObject = eventList.waitForNext();
Trace.message("TimerThread.run: EventObject type " + eventObject.eventType + " being processed");
if (eventObject.eventType == EventList.SWITCH_ITEM_TO_POSTED) {
Trace.message("TimerThread: Switch Item to POSTED");
try {
AuctionControl.startAuction(eventObject.id);
}
catch (SQLException ex) {
Trace.error("TimerThread: AuctionControl.startAuction failed with exception " + ex.toString());
Trace.exception(ex);
}
}
else if (eventObject.eventType == EventList.SWITCH_ITEM_TO_CLOSED) {
Trace.message("TimerThread: Switch Item to CLOSED");
try {
AuctionControl.endAuction(eventObject.id);
}
catch (SQLException ex) {
Trace.error("TimerThread: AuctionControl.endAuction failed with exception " + ex.toString());
Trace.exception(ex);
}
}
else if (eventObject.eventType == EventList.UNLOCK_REGISTERED_USER) {
Trace.message("TimerThread: Unlock registered user");
try {
AuctionControl.unlockRegisteredUser(eventObject.id);
}
catch (SQLException ex) {
Trace.error("TimerThread: AuctionControl.unlockRegisteredUser failed with exception " + ex.toString());
Trace.exception(ex);
}
}
else {
Trace.error("TimerThread: Unrecognized event type " + eventObject.eventType);
}
}
}
catch (InterruptedException ex) {
Trace.message("TimerThread interrupted");
return;
}
}
}