java实现服务器文件打包zip并下载的示例(边打包边下载)

使用该方法,可以即时打包文件,一边打包一边传输,不使用任何的缓存,让用户零等待!

/**
 *
 * mysocket 客户端 socket
 * @param file 待打包的文件夹或文件
 * @param filename 打包下载的文件名
 * @throws ioexception
 */

private void down(file file, string filename) throws ioexception {
 outputstream outputstream = mysocket.getoutputstream();
 stringbuffer sb = new stringbuffer("http/1.1 200 ok\r\n");
 sb.append("server: java/1.1\r\n");
 sb.append("content-type:application/octet-stream;charset=utf-8\r\n");
 //sb.append("user-agent: mozilla/4.0 (compatible;msie6.0;windows nt 5.0)\r\n");
 sb.append("content-disposition: attachment; filename=" + filename
   + "\r\n");
 sb.append("transfer-encoding: chunked\r\n");
 sb.append("connection: keep-alive\r\n\r\n");
 outputstream.write(sb.tostring().getbytes());
 outputstream.flush();
 zipcompressor zipcompressor = new zipcompressor(new myoutputstream(
   outputstream));
 zipcompressor.compress(file);
 system.out.println("zip end");  
 system.out.println("write '0\\r\\n\\r\\n'");
 outputstream.write("0\r\n\r\n".getbytes());//transfer-encoding: chunked传输结束标记
 outputstream.flush();
 outputstream.close();
 system.out.println("download stop");
 try {
  mysocket.close();
 } catch (throwable t) {
 }
}

package cn.liangjintang.webserver.zipfile;

import java.io.bufferedinputstream;
import java.io.file;
import java.io.fileinputstream;
import java.io.outputstream;
import java.lang.reflect.field;
import java.util.zip.crc32;
import java.util.zip.checkedoutputstream;
import java.util.zip.zipentry;
import java.util.zip.zipoutputstream;

public class zipcompressor {
 static final int buffer = 8192;
 private outputstream outputstream;
 public zipcompressor(myoutputstream outputstream) {
  this.outputstream=outputstream;
 }
 public void compress(file file) {
  if (!file.exists())
   throw new runtimeexception(file.getabsolutepath() + "不存在！");
  try {
   checkedoutputstream cos = new checkedoutputstream(outputstream,
     new crc32());
   zipoutputstream out = new zipoutputstream(cos);
   string basedir = "";
   compress(file, out, basedir);
   out.close();//必须关闭,这样才会写入zip的结束信息,否则zip文件不完整.若想继续写入,可重写outputstream.close()方法
  } catch (exception e) {
   throw new runtimeexception(e);
  }
 }

 private void compress(file file, zipoutputstream out, string basedir) {
  //判断是目录还是文件
  if (file.isdirectory()) {
   system.out.println("压缩：" + basedir + file.getname());
   this.compressdirectory(file, out, basedir);
  } else {
   system.out.println("压缩：" + basedir + file.getname());
   this.compressfile(file, out, basedir);
  }
 }

 // 压缩一个目录
 private void compressdirectory(file dir, zipoutputstream out, string basedir) {
  if (!dir.exists())
   return;

  file[] files = dir.listfiles();
  for (int i = 0; i < files.length; i++) {
   /** 递归 */
   compress(files[i], out, basedir + dir.getname() + "/");
  }
 }

 //压缩一个文件
 private void compressfile(file file, zipoutputstream out, string basedir) {
  if (!file.exists()) {
   return;
  }
  try {
   bufferedinputstream bis = new bufferedinputstream(
     new fileinputstream(file));
   zipentry entry = new zipentry(basedir + file.getname());
   out.putnextentry(entry);
   int count;
   byte data[] = new byte[buffer];
   while ((count = bis.read(data, 0, buffer)) != -1) {
    out.write(data, 0, count);
   }
   bis.close();
  } catch (exception e) {
   throw new runtimeexception(e);
  }
 }
}

package cn.liangjintang.webserver.zipfile;

import java.io.filteroutputstream;
import java.io.ioexception;
import java.io.outputstream;

public class myoutputstream extends filteroutputstream {
 public myoutputstream(outputstream out) {
  super(out);
 }

 final byte[] onebytes = "1\r\n".getbytes();
 final byte[] rnbytes = "\r\n".getbytes();

 public void write(int b) throws ioexception {
  out.write(onebytes);//字节数1+crlf
  out.write(b);//数据实体
  out.write(rnbytes);//crlf
 }

 public void write(byte[] b) throws ioexception {
  out.write(integer.tohexstring(b.length).getbytes());//字节数,十六进制
  out.write(rnbytes);//crlf
  out.write(b);//数据实体
  out.write(rnbytes);//crlf
 }

 public void write(byte[] b, int off, int len) throws ioexception {
  out.write(integer.tohexstring(len - off).getbytes());//字节数,十六进制
  out.write(rnbytes);//crlf
  out.write(b, off, len);//数据实体
  out.write(rnbytes);//crlf
 }

 /**
  * 重写该方法,否则outputstream会被关闭,其他的数据<br/>
  * (如transfer-encoding: chunked传输结束标记)就不能再继续写入了
  */
 public void close() throws ioexception {
 }
}