connection.setChunkedStreamingMode(chunkSize);
使用这个代码就可以了，connection为 HttpURLConnection的实例
完整代码如下：
/* 上传文件至Server的方法 */ private void uploadFile() { String end = "\r\n"; String twoHyphens = "--"; String boundary = "*****"; try { URL url =new URL(actionUrl); HttpURLConnection con=(HttpURLConnection)url.openConnection(); con.setChunkedStreamingMode(51200); /* 允许Input、Output，不使用Cache */ con.setDoInput(true); con.setDoOutput(true); con.setUseCaches(false); /* 设置传送的method=POST */ con.setRequestMethod("POST"); /* setRequestProperty */ con.setRequestProperty("Connection", "Keep-Alive"); con.setRequestProperty("Charset", "UTF-8"); con.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary); /* 设置DataOutputStream */ DataOutputStream ds = new DataOutputStream(con.getOutputStream()); ds.writeBytes(twoHyphens + boundary + end); ds.writeBytes("Content-Disposition: form-data; " + "name=\"file1\";filename=\"" + newName +"\"" + end); ds.writeBytes(end); /* 取得文件的FileInputStream */ FileInputStream fStream = new FileInputStream(uploadFile); /* 设置每次写入1024bytes */ int bufferSize = 1024; byte[] buffer = new byte[bufferSize]; int length = -1; /* 从文件读取数据至缓冲区 */ while((length = fStream.read(buffer)) != -1) { /* 将资料写入DataOutputStream中 */ ds.write(buffer, 0, length); } ds.writeBytes(end); ds.writeBytes(twoHyphens + boundary + twoHyphens + end); /* close streams */ fStream.close(); ds.flush(); /* 取得Response内容 */ InputStream is = con.getInputStream(); int ch; StringBuffer b =new StringBuffer(); while( ( ch = is.read() ) != -1 ) { b.append( (char)ch ); } /* 将Response显示于Dialog */ showDialog(b.toString().trim()); /* 关闭DataOutputStream */ ds.close(); } catch(Exception e) { showDialog(""+e); } }