Java_file_send.rar_java sendfile

/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package java_file_send; import java.io.BufferedInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.RandomAccessFile; import java.net.HttpURLConnection; import java.net.URL; /*文件传送客户端，获取远程文件 */ public class Download { public void Download(){} //确定文件是否正在下载但下载未完成 private boolean FileExist(String PathAndFile){ File file = new File(PathAndFile); if(file.exists()) return true; else return false; } //确定已下载文件大小 private long FileSize(String PathAndFile){ File file = new File(PathAndFile); return file.length(); } //将完成下载的文件更名，去掉 .tp private void FileRename(String fname,String nname){ File file = new File(fname); file.renameTo(new File(nname)); file.delete(); } public static void main(String[] args) { URL url = null; HttpURLConnection urlc = null; DataOutputStream dos = null; BufferedInputStream bis = null; FileOutputStream fos = null; //文件路径和文件名 String localfile = "C:\\Users\\Administrator\\Desktop" + "\\main.html"; //未下载完文件加 .tp 扩展名 String localfile_bak = localfile + ".tp"; Download gco = new Download(); long filesize = 0; long start = System.currentTimeMillis(); int len = 0; byte[] bt = new byte[1024]; RandomAccessFile rafile = null; //要下载的文件总大小 long totalsize = 0; try{ url = new URL("https://www.duba.com/?f=liebao"); urlc = (HttpURLConnection) url.openConnection(); totalsize = Long.parseLong(urlc.getHeaderField("Connection-Length")); System.out.println("下载文件大小："+totalsize); //先断开，再连接，不然会报已经连接的错 urlc.disconnect(); urlc = (HttpURLConnection) url.openConnection(); //确定文件是否存在，采用断点续传，通过查看下载文件是否在本地有.tp有扩展同名文件 if(gco.FileExist(localfile_bak)){ System.out.println("文件续传中..."); //取得文件大小，以确定写入位置 filesize = gco.FileSize(localfile_bak); System.out.println("filesize"+filesize); //设置断点续传的开始位置，- 不能少 urlc.setRequestProperty("RANGE", "bytes="+filesize+"-"); //设置接受信息 urlc.setRequestProperty("Accept", "image/gif,image/x-xb" + "itmap,application/msword,*/*"); //随机访问读取 rafile = new RandomAccessFile(localfile_bak,"rw"); //定位指针到filesize位置 rafile.seek(filesize); bis = new BufferedInputStream(urlc.getInputStream()); //循环获取文件 while((len=bis.read(bt))>0){ rafile.write(bt,0,len); } System.out.println("文件续传接收完毕！"); }else //采用原始下载方式 { //没有下载完的文件命名为 .bak fos = new FileOutputStream(localfile_bak); dos = new DataOutputStream(fos); System.out.println("正在接收文件..."); int test = 0; //循环获取文件 while((len = bis.read(bt))>0){ dos.write(bt,0,len); test++; if(test==50)//测试，删除后可以正常下载 break; } } System.out.println("共用时："+(System.currentTimeMillis()-start)/1000); if(bis != null) bis.close(); if(dos != null) dos.close(); if(fos != null) fos.close(); if(rafile != null) rafile.close(); System.out.println("localfile_bak:"+gco.FileSize(localfile_bak)); //下载完毕后，重命名文件 if(gco.FileSize(localfile_bak)==totalsize){ gco.FileRename(localfile_bak, localfile); } System.exit(0); }catch(Exception e){ try{ if(bis != null) bis.close(); if(dos != null) dos.close(); if(fos != null) fos.close(); if(rafile != null) rafile.close(); }catch(IOException f){ f.printStackTrace(); } e.printStackTrace(); } System.exit(0); } }