简单实用后台任务执行框架（Struts2+Spring+AJAX前端web界面可以获取进度）

使用场景：

在平常web开发过程中，有时操作员要做一个后台会运行很长时间的任务（如上传一个大文件到后台处理），而此时前台页面仍需要给用户及时的进度信息反馈，同时还要避免前台页面超时。

框架介绍：

本架构采用Struts+Spring+AJAX(jquery)方式实现，前台提交任务到后台，然后通过AJAX方式周期性获取任务进度，展示给用户看。

本框架支持提交任务、查看任务进展、停止任务、删除任务。

使用java线程池的技术来执行任务，避免不停的生成新的线程;

代码下载（内含使用样例）：

https://github.com/jerrymousecn/daemo_tasks

下载包说明：

1）demo/daemonTasks.war为tomcat发布包(zip格式)，可以直接放到tomcat的webapps目录；

2）demo/demo_source目录是eclipse样例项目代码

3）source目录是本框架源代码

主要代码：

1.DaemonTask.java

后台任务基础类

package cn.jerry.tools.tasks;

import java.util.Date;

public abstract class DaemonTask implements Runnable {
	private String taskID;
	private String taskName;
	private String taskDesc;
	private boolean isStartedFlag = false;;
	private boolean isTerminated = false;;
	private int progress;
	private Date startTime;
	private Date terminatedTime;
	protected boolean toStopFlag = false;

	protected abstract void execute();

	protected void setProgress(int progress) {
		this.progress = progress;
	}

	public void run() {
		this.isStartedFlag = true;
		this.execute();
		this.isTerminated = true;
		this.terminatedTime = new Date();
	}

	public String getTaskID() {
		return taskID;
	}

	public void setTaskID(String taskID) {
		this.taskID = taskID;
	}

	public boolean isStarted() {
		return isStartedFlag;
	}

	public boolean getIsTerminated() {
		return isTerminated;
	}
	public void setToStopFlag(boolean toStopFlag) {
		this.toStopFlag = toStopFlag;
	}

	public Date getStartTime() {
		return startTime;
	}

	public Date getTerminatedTime() {
		return terminatedTime;
	}

	public int getProgress() {
		return progress;
	}

	public String getTaskName() {
		return taskName;
	}

	public void setTaskName(String taskName) {
		this.taskName = taskName;
	}

	public String getTaskDesc() {
		return taskDesc;
	}

	public void setTaskDesc(String taskDesc) {
		this.taskDesc = taskDesc;
	}

}

2.TaskManager.java

后台任务管理类，支持添加任务，停止任务，删除任务，查看任务，对已完成任务进行定期清理，获取任务进度

package cn.jerry.tools.tasks;

import java.util.Collections;
import java.util.Date;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TaskManager {
	private static TaskManager taskManager = new TaskManager();
	private ExecutorService executorService = Executors.newCachedThreadPool();
	private ConcurrentMap<String, DaemonTask> taskMap = new ConcurrentHashMap<String, DaemonTask>();
	private final int TASK_NOT_FOUND = -1;
	private TaskCleaner taskCleaner = new TaskCleaner(taskMap);
	private Timer timer = new Timer();
	private final int CLEAN_PERIOD = 200000;  //in milliseconds

	private String getUniqueID() {
		return UUID.randomUUID().toString();
	}

	private TaskManager() {
		startTerminatedTaskCleanTimer();
	}

	private void startTerminatedTaskCleanTimer() {
		timer.schedule(taskCleaner, 0, CLEAN_PERIOD);
	}

	private void stopTerminatedTaskCleanTimer() {
		timer.cancel();
	}

	public static TaskManager getInstance() {
		return taskManager;
	}

	public synchronized String addTaskAndStart(DaemonTask task) {
		String taskID = getUniqueID();
		task.setTaskID(taskID);
		taskMap.put(taskID, task);
		executorService.execute(task);
		return taskID;
	}

	public synchronized void stopTask(String taskID) {
		DaemonTask task = getTask(taskID);
		if (task != null) {
			task.setToStopFlag(true);
		}
	}
	public synchronized void delFinishedTask(String taskID) {
		DaemonTask task = getTask(taskID);
		if (task != null) {
			if (task.getIsTerminated()) {
				taskMap.remove(taskID);
			}
		}
	}

	public DaemonTask getTask(String taskID) {
		return taskMap.get(taskID);
	}
	public Map<String, DaemonTask> getTasksForView() {
		Map<String, DaemonTask> map = Collections.unmodifiableMap(taskMap);
		return map;
	}

	public int getProgress(String taskID) {
		int progress = TASK_NOT_FOUND;
		DaemonTask task = getTask(taskID);
		if (task != null) {
			progress = task.getProgress();
		}
		return progress;
	}

}

class TaskCleaner extends TimerTask {
	private ConcurrentMap<String, DaemonTask> taskMap;

	public TaskCleaner(ConcurrentMap<String, DaemonTask> taskMap) {
		this.taskMap = taskMap;
	}

	@Override
	public void run() {
		for (Entry<String, DaemonTask> entry : taskMap.entrySet()) {
			String taskID = entry.getKey();
			DaemonTask task = entry.getValue();
			if (task.getIsTerminated()) {
				Date terminatedTime = task.getTerminatedTime();
				Date now = new Date();

				long timeOffset = getTimeOffset(terminatedTime, now);
				if (timeOffset > 10000) {
					taskMap.remove(taskID);
					System.out.println("task: " + taskID + " is removed");
				}
			}
		}
	}

	private long getTimeOffset(Date date1, Date date2) {
		long time1 = date1.getTime();
		long time2 = date2.getTime();
		long offset = time2 - time1;
		if (offset < 0) {
			offset = -offset;
		}
		return offset;
	}
}

3.任务样例TestTask.java

关键点需要注意： 方法中需要自行计算进度（完成时，进度应设置为100），并且要对toStopFlag进行判断，用于终止任务。

package cn.jerry.tools.tasks;

public class TestTask extends DaemonTask {

	@Override
	protected void execute() {
		for (int i = 0; i < 10; i++) {
			if(this.toStopFlag==false)
			{
				int progress = (i + 1) * 100 / 10;
				try {
					Thread.sleep(1000);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				this.setProgress(progress);
			}
		}
	}
}

4.前台查询状态页面getTaskResult.jsp：

<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
<link rel="stylesheet" href="css/jquery-ui.css">
<script src="js/jquery-ui.js"></script>
<link rel="stylesheet" href="css/style.css">
<script type="text/javascript">
var intervalId; 
function trim(str){
	return str.replace(/(^s*)|(s*$)/g, ""); 
} 
function getprogress() {
	htmlobj=$.ajax({url:"getTaskProgress.jsp?taskid="+'<s:property value="taskid"/>',cache:false,async:false});
	str = trim(htmlobj.responseText);
	$("#myDiv").html(str);
	$( "#progressbar" ).progressbar({
	      value: parseInt(str)
	});
	if(parseInt(str)>=100)
	{
		clearInterval(intervalId);
	}
}

$(document).ready(function(){
	intervalId = setInterval(getprogress, 1000);
});

</script>
</head>
<body>
Task [<s:property value="taskName"/>]progress:
	<div id="progressbar"></div>
	<div id="myDiv"></div>
</body>
</html>

5.相关截图

1）进度页面截图：

2）查看任务列表

声明：

本框架中使用的进度条代码实现来自以下网站，版权不属于本人，本框架仅用于学习交流。

http://jqueryui.com/progressbar/#animated

转载请注明出处：http://blog.csdn.net/u014569459/article/details/26873097