getfile.java

一个简单的多线程下载程序

package com.network.flashget;

import java.net.*;
import javax.swing.JOptionPane;
import java.io.IOException;
import java.io.File;
import java.io.RandomAccessFile;

class GetFile
{
	//定义关于文件的一些变量----------------------------------------
	private long fileLength = 0;
	private int threadNum = 0;
	private URL url = null;
	public static final long FileNotFound = 0;
	public static final long FileSizeUnknown = 1;
	private String saveTo = null;
	private String fileName = null;
	
	//构造函数，获得文件长度，下载线程数，存储路径及文件名称等--------------
	GetFile(URL url,int threadNum,String saveTo,String fileName)
	{
		long result = 0;
		try
		{
			URLConnection urlConn = url.openConnection();
			result = urlConn.getContentLength();
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		this.fileLength = result;
		this.threadNum = threadNum;
		this.url = url;
		this.saveTo = saveTo;
		this.fileName = fileName;
		
		try
		{
			File file = new File(saveTo);
			if (!file.exists())
			{
				file.createNewFile();
			}
			RandomAccessFile tempFile = new RandomAccessFile(file,"rw");
			tempFile.setLength(fileLength);
			
			tempFile.close();
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
	}
		
		
    //用来调用下载管理类TaskManage，并运行Manage--------------------------------------------
    public void connectTaskManager()
    {
    	MainWindow.taskCount++;
    	TaskManage taskManager = new TaskManage(url,saveTo,fileName,fileLength,threadNum);
    	System.out.println("Content Length:"+fileLength);
    	taskManager.assignMission();
    	MainWindow.taskDownList.add(taskManager);
    	System.out.println("TaskDownList Length:"+MainWindow.taskDownList.size());
    	
    	//将该任务加到运行链表中----------------------------------------------------------------
    	MainWindow.runningList.add(new Boolean(true));
    	
    	//说明该任务不是从文件读出来的----------------------------------------------------------
    	MainWindow.statusList.add(new Boolean(true));
       	
       	//将任务情况加到tableDown表格中去-------------------------------------------------------
    	String tempStatus = "Downing";
       	String tempName = taskManager.fileName;
    	long tempLength =  taskManager.fileLength;
    	float tempRate = taskManager.downRate;
    	String tempSave = taskManager.saveTo;
    	int tempThreadNum = taskManager.threadNum;
    	String tempURL = taskManager.url.toString();
    	
    	Object[] info = {tempStatus,tempName,tempLength,0,tempRate,tempSave,tempThreadNum,tempURL};
		MainWindow.tableDownModel.addRow(info);
    	
    	//将任务情况加到tableDownDetail表格中去-------------------------------------------------
    	while(MainWindow.tableDownDetail.getRowCount()>0)
       	{
       		MainWindow.tableDownDetailModel.removeRow(0);
       	}
        for(int j = 0;j < (taskManager.taskThreadList).size();j++)
       	{
     		int threadNo = j+1;
       	//	String tempName = taskManager.fileName;
       		long tempStart = ((TaskThread)(taskManager.taskThreadList.get(j))).finalStart;
	   		long tempEnd = ((TaskThread)(taskManager.taskThreadList.get(j))).endPosition;
			long tempDown = ((TaskThread)(taskManager.taskThreadList.get(j))).downLength;
		//	String tempURL = taskManager.url.toString();
		
			Object[] detailInfo = {threadNo,tempName,tempStart,tempEnd,tempDown,tempURL};
			MainWindow.tableDownDetailModel.addRow(detailInfo);
		}
			
		taskManager.runSubThread();	
    	taskManager.start();
    	System.out.println("Task Start");  	
    } 	
}