电脑通过TCP/IP向手机发送文件 发现接收到的APK文件无法安装出现解析包出错

if (file.exists()) {

					filePath.setText("文件发送中请稍候");

					long len = file.length();

					try {

						Socket s = new Socket(IP,7777);

						DataOutputStream dos = new DataOutputStream(s.getOutputStream());

						dos.writeUTF(file.getName());

						dos.flush();

						dos.close();

						s.close();

						

						Socket wenjian = new Socket(IP, 6666);

						DataOutputStream out = new DataOutputStream(new BufferedOutputStream(wenjian.getOutputStream()));

						InputStream fi = new FileInputStream(file);

						byte[] buf = new byte[(int)len];

						int offset = 0;

						int numRead = 0;

						while(offset < buf.length && (numRead = fi.read(buf, offset, buf.length - offset)) >= 0 ) {

							offset += numRead;

						}

						

						if (offset != buf.length) {

							System.out.print("chucuo");

							filePath.setText("文件发送出错请重新发送");

						}

						fi.close();

						out.write(buf);

						out.flush();

						out.close();

						wenjian.close();

						//send.setClickable(true);

						filePath.setText("文件发送完毕");

					} catch (UnknownHostException e) {

						e.printStackTrace();

					} catch (IOException e) {

						e.printStackTrace();

					}

				} else {

					Toast.makeText(Tab1Activity.this, "文件路径有误请重新填写或选择", Toast.LENGTH_SHORT).show();

				}

			}