HTTP上传

与文件下载相比，文件上传的场合不是很多，通常用于上传用户头像、朋友圈发布图片/视频动态等等，而且上传文件需要服务器配合，所以容易被app开发者忽略。就上传的形式来说，app一般采用http上传文件，很少用ftp上传文件。

HttpURLConnection上传

很可惜Android没有提供专门的文件上传工具类，所以我们要自己写代码实现上传功能了。其实也不难，一样是按照普通网络访问的POST流程，只是要采用“multipart/form-data”方式来分段传输。另外文件上传需要运用打开文件的对话框，文件对话框的介绍参见《 Android开发笔记（二十三）文件对话框FileDialog》。

下面是HttpURLConnection上传文件的工具类代码：

import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;public class UploadUtil {private static final String TAG = "UploadUtil";public static String upload(String uploadUrl, String uploadFile) {String fileName = "";int pos = uploadFile.lastIndexOf("/");if (pos >= 0) {fileName = uploadFile.substring(pos + 1);}String end = "\r\n";String Hyphens = "--";String boundary = "WUm4580jbtwfJhNp7zi1djFEO3wNNm";try {URL url = new URL(uploadUrl);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setDoInput(true);conn.setDoOutput(true);conn.setUseCaches(false);conn.setRequestMethod("POST");conn.setRequestProperty("Connection", "Keep-Alive");conn.setRequestProperty("Charset", "UTF-8");conn.setRequestProperty("Content-Type","multipart/form-data;boundary=" + boundary);DataOutputStream ds = new DataOutputStream(conn.getOutputStream());ds.writeBytes(Hyphens + boundary + end);ds.writeBytes("Content-Disposition: form-data; "+ "name=\"file1\";filename=\"" + fileName + "\"" + end);ds.writeBytes(end);FileInputStream fStream = new FileInputStream(uploadFile);// 每次写入1024字节int bufferSize = 1024;byte[] buffer = new byte[bufferSize];int length = -1;// 将文件数据写入到缓冲区while((length = fStream.read(buffer)) != -1) { ds.write(buffer, 0, length);}ds.writeBytes(end);ds.writeBytes(Hyphens + boundary + Hyphens + end);fStream.close();ds.flush();// 获取返回内容InputStream is = conn.getInputStream();int ch;StringBuffer b = new StringBuffer();while ((ch = is.read()) != -1) {b.append((char) ch);}ds.close();return "SUCC";} catch (Exception e) {e.printStackTrace();return "上传失败:" + e.getMessage();}}
}

android-async-http上传

HttpURLConnection需要开发者自己拼接请求包，容易出错，并且处理单一不够灵活，因此涌现了几个开源的http框架，方便开发者进行http通信的编码。android-async-http是这其中使用较多的一个网络请求框架，它的项目地址在 https://github.com/loopj/android-async-http 。

据官方介绍，android-async-http是基于Apache HttpClient库之上的一个异步网络请求处理库，网络处理均基于Android的非UI线程，通过回调方法处理请求结果。这里我们使用该库进行文件上传，主要用到AsyncHttpClient类的post方法，要上传的文件信息放在RequestParams对象中。

下面是android-async-http上传文件的工具类代码：

import java.io.File;import com.example.exmupload.MainActivity;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.RequestParams;import android.util.Log;public class AsyncUtil {private static final String TAG = "AsyncUtil";public static String upload(final MainActivity act, String uploadServlet, String filePath, boolean isBinary) {try {//服务端的commons-fileupload只支持multipart/form-data方式//application/octet-stream表示任意的二进制文件，包括图片、音频、视频、压缩文件等等String contentType = "application/octet-stream";//String contentType = "multipart/form-data";RequestParams params = new RequestParams();if (isBinary == true) {params.put("file", new File(filePath), contentType);} else {params.put("file", new File(filePath));}Log.d(TAG, "contentType="+contentType);AsyncHttpClient client = new AsyncHttpClient();//AsyncHttpResponseHandle不在ui线程运行，不能直接操作ui//如果在此处定义AsyncHttpResponseHandle对象，则运行报错：//java.lang.IllegalArgumentException: Synchronous ResponseHandler used in AsyncHttpClient. You should create your response handler in a looper thread or use SyncHttpClient instead.client.post(uploadServlet, params, act.mAsyncHandler);return "uploadByFile";} catch (Exception e) {e.printStackTrace();return e.getMessage();}}// //下面代码在MainActivity.java中定义
//  public AsyncHttpResponseHandler mAsyncHandler = new AsyncHttpResponseHandler() {
//      @Override
//      public void onSuccess(int status, Header[] headers, byte[] data) {
//          String result = "文件上传成功!";
//          Message msg = Message.obtain();
//          msg.what = ASYNC;
//          msg.obj = result;
//          mHandler.sendMessage(msg);
//      }
//
//      @Override
//      public void onFailure(int status, Header[] headers, byte[] data, Throwable e) {
//          String result = "文件上传失败!"+e.getMessage();
//          Message msg = Message.obtain();
//          msg.what = ASYNC;
//          msg.obj = result;
//          mHandler.sendMessage(msg);
//      }
//  };}

Retrofit上传

Retrofit是网络请求框架中的后起之秀，它的项目地址在 https://github.com/square/retrofit 。据官方介绍，Retrofit是一个类型安全的REST客户端，用于Android平台。Retrofit基于注解方式，提供了JSON to POJO(Plain Ordinary Java Object,简单Java对象)、POJO to JSON、网络请求(POST/GET/PUT/DELETE)等通信行为的封装。

Retrofit依赖okhttp库，早期的版本用的是okhttp2（如okhttp-2.5.0.jar），最新的版本如retrofit-2.1.0.jar用的是okhttp3（如okhttp-3.3.1.jar），所以工程引用Retrofit库时，要注意导入正确的okhttp库。这里我们通过文件上传来演示Retrofit的使用方法，因为采用了注解方式，所以不太方便文字说明，还是直接上代码好了。

下面是Retrofit上传文件的工具类代码：

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;import com.example.exmupload.MainActivity;import okhttp3.MediaType;
import okhttp3.RequestBody;
import okhttp3.ResponseBody;import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.http.Multipart;
import retrofit2.http.PartMap;
import retrofit2.http.POST;import android.util.Log;
import android.webkit.MimeTypeMap;public class RetrofitUtil {private static final String TAG = "RetrofitUtil";public interface ApiInterface {//这里的POST是不带ip也不带域名的地址，下面uploadHost才带ip/域名和端口，如http://192.168.0.212:8080/@Multipart@POST("UploadTest/uploadServlet")Call<ResponseBody> upload(@PartMap Map<String, RequestBody> params);}public static void upload(final MainActivity act, String uploadHost, String filePath) {File file1 = new File(filePath);Retrofit retrofit = new Retrofit.Builder().baseUrl(uploadHost).build();ApiInterface apiService = retrofit.create(ApiInterface.class);// 获取文件真实的内容类型
//      String mimeType = MimeTypeMap.getSingleton()
//              .getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(file1.getPath()));
//      RequestBody fileBody = RequestBody.create(MediaType.parse(mimeType), filePath);RequestBody fileBody = RequestBody.create(MediaType.parse("multipart/form-data"), filePath);Map<String, RequestBody> params = new HashMap<>();// 如果要上传多个文件，可对该Map对象进行put操作params.put("file\"; filename=\"" + file1.getName() + "", fileBody);Call<ResponseBody> call = apiService.upload(params);call.enqueue(new Callback<ResponseBody>() {@Overridepublic void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {try {String jsonString = new String(response.body().bytes()); // 这就是返回的json字符串了。Log.d(TAG, "onResponse succ : "+jsonString);act.notify(act.RETROFIT, "onResponse succ "+jsonString);} catch (IOException e) {e.printStackTrace();act.notify(act.RETROFIT, "onResponse "+e.getMessage());}}@Overridepublic void onFailure(Call<ResponseBody> call, Throwable throwable) {Log.d(TAG, "onFailure : "+throwable.getMessage());act.notify(act.RETROFIT, "onFailure "+throwable.getMessage());}});}}

服务器接收文件

commons-fileupload

文件上传需要服务器配合，服务端若用java编码，则可通过commons-fileupload来接收文件。commons-fileupload是个通用的各类网络协议通信包，包括ftp/telnet/smtp/pop3等协议。该包依赖于commons-io库，它们的下载地址如下：
commons-fileupload-1.2.1.jar https://mirrors.tuna.tsinghua.edu.cn/apache/commons/fileupload/binaries/
commons-io-1.4.jar https://mirrors.tuna.tsinghua.edu.cn/apache/commons/io/binaries/

下面是服务端采用commons-fileupload接收文件的代码例子：

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.util.Streams;public class UploadServlet extends HttpServlet {private static final long serialVersionUID = 1L;public UploadServlet() {super();}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doPost(request, response);}@SuppressWarnings("unchecked")protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("request.getContentType()="+request.getContentType());response.setContentType("text/html");response.setCharacterEncoding("UTF-8");Writer o = response.getWriter();//首先判断Content-Type是不是multipart/form-data。同时也判断了form的提交方式是不是postif (ServletFileUpload.isMultipartContent(request)) {request.setCharacterEncoding("utf-8");// 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload   DiskFileItemFactory factory =  new DiskFileItemFactory();//设置文件存放的临时文件夹，这个文件夹要真实存在File fileDir = new File("../webapps/");if (fileDir.isDirectory() && fileDir.exists()==false) {fileDir.mkdir();}factory.setRepository(fileDir);//设置最大占用的内存factory.setSizeThreshold(1024000);//创建ServletFileUpload对象ServletFileUpload sfu = new ServletFileUpload(factory);sfu.setHeaderEncoding("utf-8");//设置单个文件最大值byte sfu.setFileSizeMax(102400000);//所有上传文件的总和最大值byte   sfu.setSizeMax(204800000);List<FileItem> items =  null;try {items = sfu.parseRequest(request);System.out.println("items.size()="+items.size());} catch(Exception e) {   e.printStackTrace();   }Iterator<FileItem> iter = items==null?null:items.iterator();//文件上传后存放的路径目录File dir = new File("D:/");if (dir.exists()==false) {dir.mkdirs();}  while (iter!=null && iter.hasNext()) {FileItem item = (FileItem) iter.next();if (item.isFormField()) { //如果传过来的是普通的表单域System.out.print("普通的表单域:");   System.out.print(new String(item.getFieldName()) + "  ");   System.out.println(new String(item.getString("UTF-8")));   } else if (!item.isFormField()) { //文件域System.out.println("源文件:" + item.getName());String fileName = item.getName();if (fileName.indexOf("\\") >= 0) {fileName = item.getName().substring(item.getName().lastIndexOf("\\"));}BufferedInputStream in = new BufferedInputStream(item.getInputStream());BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(new File(dir.getAbsolutePath()+ fileName))); Streams.copy(in, out, true);o.write("文件上传成功");}}} else {System.out.println("表单的Content-Type错误");} }}

FTP上传

普通FTP

在从前带宽有限的互联网时代，FTP共享影视资源曾经盛行一时，如今宽带普及了，特别是步入移动互联网时代，FTP用的便越来越少了。不管怎样，作为一个技术手段，我们还是温习一下FTP上传文件的用法，java上可导入commons-net-3.3.jar，该库是集成了常见的网络通讯协议，包括但不限于：ftp、telnet、smtp、pop3等等。

commons-net进行FTP上传用的是FTPClient类，下面是FTPClient上传文件的工具类代码：

import java.io.FileInputStream;
import java.io.IOException;import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;public class FTPUtil {private static String mUurl;private static String mPort;private static String mUsername;private static String mPassword;public static void setUser(String url, String port, String username, String password) {mUurl = url;mPort = port;mUsername = username;mPassword = password;}public static String upload(String remotePath, String filePath, String fileName) {FTPClient ftpClient = new FTPClient();String result = "SUCC";try {ftpClient.connect(mUurl, Integer.parseInt(mPort));boolean loginResult = ftpClient.login(mUsername, mPassword);int returnCode = ftpClient.getReplyCode();if (loginResult && FTPReply.isPositiveCompletion(returnCode)) { //登录成功ftpClient.makeDirectory(remotePath);// 设置上传目录ftpClient.changeWorkingDirectory(remotePath);ftpClient.setBufferSize(1024);ftpClient.setControlEncoding("UTF-8");ftpClient.enterLocalPassiveMode();FileInputStream fis = new FileInputStream(filePath + fileName);ftpClient.storeFile(fileName, fis);} else { //登录失败result = "FAIL";}} catch (IOException e) {e.printStackTrace();result = "FTP客户端出错！" + e.getMessage();} finally {try {ftpClient.disconnect();} catch (IOException e) {e.printStackTrace();result = "关闭FTP连接发生异常！" + e.getMessage();}}return result;}
}

安全的SFTP

SFTP是Secure FTP的简称，顾名思义它比FTP要安全。不过对于普通用户来说，SFTP用得比FTP还少，就不啰嗦了。

调用SFTP可导入JSch库，最新的jar包是jsch-0.1.53.jar，该库操作SFTP主要用ChannelSftp类，下面是JSch上传文件的工具类代码：

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Properties;
import java.util.Vector;import android.util.Log;import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.ChannelSftp.LsEntry;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;public class SFTPUtil {private static final String TAG = "SFTPUtil";public static int SUCC = 0;public static int FAIL = -1;//连接sftp服务器public static ChannelSftp connect(String host, int port, String username, String password) {ChannelSftp sftp = null;try {JSch jsch = new JSch();jsch.getSession(username, host, port);Session session = jsch.getSession(username, host, port);session.setPassword(password);Properties config = new Properties();config.put("StrictHostKeyChecking", "no");session.setConfig(config);session.connect();Channel channel = session.openChannel("sftp");channel.connect();sftp = (ChannelSftp) channel;Log.d(TAG, "Connected to " + host + ".");} catch (Exception e) {e.printStackTrace();}return sftp;}//上传文件public static String upload(ChannelSftp sftp, String directory, String uploadFile) {try {sftp.cd(directory);File file = new File(uploadFile);sftp.put(new FileInputStream(file), file.getName());Log.d(TAG, "Upload succ. " + uploadFile);return "SUCC";} catch (Exception e) {e.printStackTrace();return e.getMessage();}}//下载文件public static int download(ChannelSftp sftp, String directory, String downloadFile, String saveFile) {try {sftp.cd(directory);File file = new File(saveFile);sftp.get(downloadFile, new FileOutputStream(file));Log.d(TAG, "Download succ. " + downloadFile);return SUCC;} catch (Exception e) {e.printStackTrace();return FAIL;}}//删除文件public static int delete(ChannelSftp sftp, String directory, String deleteFile) {try {sftp.cd(directory);sftp.rm(deleteFile);Log.d(TAG, "Delete succ. " + deleteFile);return SUCC;} catch (Exception e) {e.printStackTrace();return FAIL;}}//列出目录下的文件public static Vector<?> listFiles(ChannelSftp sftp, String directory) throws SftpException {//Vector容器内部保存的是LsEntry类型对象。return sftp.ls(directory);}}

下面是文件上传（包括http上传和ftp上传）的页面代码例子：

import java.util.Map;import org.apache.http.Header;import com.aqi00.lib.dialog.FileSelectFragment;
import com.aqi00.lib.dialog.FileSelectFragment.FileSelectCallbacks;
import com.example.exmupload.util.AsyncUtil;
import com.example.exmupload.util.FTPUtil;
import com.example.exmupload.util.RetrofitUtil;
import com.example.exmupload.util.SFTPUtil;
import com.example.exmupload.util.UploadUtil;
import com.jcraft.jsch.ChannelSftp;
import com.loopj.android.http.AsyncHttpResponseHandler;import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;public class MainActivity extends Activity implements OnClickListener,FileSelectCallbacks {private static final String TAG = "MainActivity";private static TextView tv_filename;private Button btn_select;private Button btn_upload;private Button btn_async;private Button btn_retrofit;private Button btn_ftp;private Button btn_sftp;private static TextView tv_result;public static String mUploadHost = "http://192.168.0.212:8080/";public static String mUploadService = "UploadTest/uploadServlet";private String mServletUrl = mUploadHost + mUploadService;@Override  public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tv_filename = (TextView) findViewById(R.id.tv_filename);btn_select = (Button) findViewById(R.id.btn_select);btn_upload = (Button) findViewById(R.id.btn_upload);btn_async = (Button) findViewById(R.id.btn_async);btn_retrofit = (Button) findViewById(R.id.btn_retrofit);btn_ftp = (Button) findViewById(R.id.btn_ftp);btn_sftp = (Button) findViewById(R.id.btn_sftp);tv_result = (TextView) findViewById(R.id.tv_result);btn_select.setOnClickListener(this);btn_upload.setOnClickListener(this);btn_async.setOnClickListener(this);btn_retrofit.setOnClickListener(this);btn_ftp.setOnClickListener(this);btn_sftp.setOnClickListener(this);}@Overridepublic void onClick(View v) {String file_path = tv_filename.getText().toString().trim();if (v.getId() == R.id.btn_select) {FileSelectFragment.show(this, new String[]{"jpg","png","gif","txt"}, null);return;}if (file_path.length() <= 0) {Toast.makeText(this, "请选择要上传的文件", Toast.LENGTH_LONG).show();return;}if (v.getId() == R.id.btn_upload) {tv_result.setText("开始HttpURLConnection上传");new ConnnectionThread(file_path).start();} else if (v.getId() == R.id.btn_async) {tv_result.setText("开始async上传");new AsyncThread(file_path).start();} else if (v.getId() == R.id.btn_retrofit) {tv_result.setText("开始retrofit上传");new RetrofitThread(file_path).start();} else if (v.getId() == R.id.btn_ftp) {new FTPThread(file_path).start();} else if (v.getId() == R.id.btn_sftp) {new SFTPThread(file_path).start();}}public void notify(int type, String message) {Message msg = Message.obtain();msg.what = type;msg.obj = message;mHandler.sendMessage(msg);}private class ConnnectionThread extends Thread {private String mFilePath;public ConnnectionThread(String file_path) {mFilePath = file_path;}@Overridepublic void run() {String result = UploadUtil.upload(mServletUrl, mFilePath);MainActivity.this.notify(COMMON, "upload :" + result);}}private class AsyncThread extends Thread {private String mFilePath;public AsyncThread(String file_path) {mFilePath = file_path;}@Overridepublic void run() {String result = AsyncUtil.upload(MainActivity.this, mServletUrl, mFilePath, true);MainActivity.this.notify(ASYNC, "upload :" + result);}}public AsyncHttpResponseHandler mAsyncHandler = new AsyncHttpResponseHandler() {@Overridepublic void onSuccess(int status, Header[] headers, byte[] data) {MainActivity.this.notify(ASYNC, "文件上传成功!");}@Overridepublic void onFailure(int status, Header[] headers, byte[] data, Throwable e) {MainActivity.this.notify(ASYNC, "文件上传失败!"+e.getMessage());}};private class RetrofitThread extends Thread {private String mFilePath;public RetrofitThread(String file_path) {mFilePath = file_path;}@Overridepublic void run() {RetrofitUtil.upload(MainActivity.this, mUploadHost, mFilePath);}}private class FTPThread extends Thread {private String mFilePath;public FTPThread(String file_path) {mFilePath = file_path;}@Overridepublic void run() {String filepath = mFilePath.substring(0, mFilePath.lastIndexOf("/")+1);String filename = mFilePath.substring(mFilePath.lastIndexOf("/")+1);FTPUtil.setUser("172.16.16.146", "21", "testftp", "testftp");String result = FTPUtil.upload("/home/testftp", filepath, filename);MainActivity.this.notify(FTP, result);}}private class SFTPThread extends Thread {private String mFilePath;public SFTPThread(String file_path) {mFilePath = file_path;}@Overridepublic void run() {ChannelSftp sftp = SFTPUtil.connect("172.16.16.133", 22, "oracle", "oracle");String result = SFTPUtil.upload(sftp, "/home/oracle", mFilePath);MainActivity.this.notify(SFTP, result);}}public int COMMON = 0;public int ASYNC = 1;public int RETROFIT = 2;public int FTP = 3;public int SFTP = 4;@SuppressLint("HandlerLeak")public Handler mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {String result = (String) msg.obj;if (msg.what == COMMON) {tv_result.setText(tv_result.getText().toString()+"\n"+result);} else if (msg.what == ASYNC) {tv_result.setText(tv_result.getText().toString()+"\n"+result);} else if (msg.what == RETROFIT) {tv_result.setText(tv_result.getText().toString()+"\n"+result);} else if (msg.what == FTP) {showTip("FTP文件上传结果："+result);} else if (msg.what == SFTP) {showTip("sftp文件上传结果："+result);}}};private void showTip(String desc) {Toast.makeText(getApplicationContext(), desc, Toast.LENGTH_SHORT).show();}@Overridepublic void onConfirmSelect(String absolutePath, String fileName,Map<String, Object> map_param) {String path = absolutePath + "/" + fileName;tv_filename.setText(path);}@Overridepublic boolean isFileValid(String absolutePath, String fileName,Map<String, Object> map_param) {return true;}}

点击下载本文用到的文件上传的工程代码

点此查看Android开发笔记的完整目录

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