java实现分段读取文件并通过HTTP上传的方法

URL url = new URL(actionUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
/** 允许Input、Output，不使用Cache */
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
/** 设定传送的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);
/** 设定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);
/** 设定每次写入1024bytes */
int bufferSize = 1024;
byte[] buffer = new byte[bufferSize];
int length = -1;
/** 从文件读取数据到缓冲区 */
while ((length = fStream.read(buffer)) != -1)
{
/** 将数据写入DataOutputStream中 */
ds.write(buffer,length);
}
ds.writeBytes(end);
ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
/** close streams */
fStream.close();
ds.flush();