flex 文件上传下载完整代码（修正版）

package upload; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoadFile extends HttpServlet { /** * */ private static final long serialVersionUID = 3089316329737765177L; public void doGet(HttpServletRequest request,HttpServletResponse resopnse) throws IOException{ doPost(request,resopnse); } public void doPost(HttpServletRequest request,HttpServletResponse resopnse) throws IOException{ try { upLoad(request); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } private boolean upLoad(HttpServletRequest request) throws Exception { int len = -1; byte[] bt = new byte[4096]; String sperator = null; String fileName = null; String savePath = "/"; //控制上传文件的大小 long fileSize = -1; request.setCharacterEncoding("utf-8"); ServletInputStream in = request.getInputStream(); len = in.readLine(bt, 0, bt.length); if (len != -1) { sperator = new String(bt, 0, len); System.out.println(sperator); sperator = sperator.substring(0, 28); System.out.println(sperator); len = -1; } do { len = in.readLine(bt, 0, bt.length); String s = new String(bt, 0, len); System.out.println(s); int index = s.indexOf("filename=\""); if (index != -1) { s = s.substring(index + 10); index = s.indexOf("\""); s = s.substring(0, index); fileName = s; len = -1; } } while (len != -1); //保存原文件名文件 FileOutputStream out = new FileOutputStream(savePath + fileName); //生成下载文件 FileOutputStream outDownLoadFile = new FileOutputStream(savePath + "down_load.jpg"); len = in.readLine(bt, 0, bt.length); String s = new String(bt, 0, len); System.out.println(s); int i = s.indexOf("Content-Type:"); if (i == -1) { System.out.print("is not file"); return false; } else { in.readLine(bt, 0, bt.length); // delete one line space len = -1; } long trancsize = 0; try { len = in.readLine(bt, 0, bt.length); while (len != -1) { s = new String(bt, 0, len); if (s.length() > 28) { s = s.substring(0, 28); if (s.equals(sperator)) { System.out.println(s); break; } } if (fileSize != -1) { if (trancsize >= fileSize) { throw new Exception("file is too big"); } } out.write(bt, 0, len); outDownLoadFile.write(bt, 0, len); trancsize += len; len = in.readLine(bt, 0, bt.length); } out.close(); outDownLoadFile.close(); return true; } catch (Exception e) { out.close(); outDownLoadFile.close(); File tmp = new File(savePath, fileName); if (!tmp.delete()) { System.out.println(e.getMessage() + ",clear error"); } return false; } } }