android retrofit 上传文件表单

 Android上传文件到服务器，通常采用构造http协议的方法，模拟网页POST方法传输文件，服务器端可以采用JavaServlet或者PHP来 接收要传输的文件。使用JavaServlet来接收文件的方法比较常见，在这里给大家介绍一个简单的服务器端使用PHP语言来接收文件的例子。

服务器端代码比较简单，接收传输过来的文件：

<?php         
                  $target_path          =          "./upload/"         ;         //接收文件目录         
                  $target_path         =          $target_path         .          basename         (          $_FILES         [         'uploadedfile'         ][         'name'         ]);         
                  if         (move_uploaded_file(         $_FILES         [         'uploadedfile'         ][         'tmp_name'         ],          $target_path         )) {         
                  echo         "The file "         .           basename         (          $_FILES         [         'uploadedfile'         ][         'name'         ]).          " has been uploaded"         ;         
                  }           else         {         
                  echo         "There was an error uploading the file, please try again!"          .          $_FILES         [         'uploadedfile'         ][         'error'         ];         
                  }         
                  ?>

手机客户端代码：

package com.figo.uploadfile; import java.io.BufferedReader; import java.io.DataOutputStream; import java.io.FileInputStream; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TextView; import android.widget.Toast; public class UploadfileActivity extends Activity { // 要上传的文件路径，理论上可以传输任何文件，实际使用时根据需要处理 private String uploadFile = "/sdcard/testimg.jpg" ; private String srcPath = "/sdcard/testimg.jpg" ; // 服务器上接收文件的处理页面，这里根据需要换成自己的 private String actionUrl = "http://10.100.1.208/receive_file.php" ; private TextView mText1; private TextView mText2; private Button mButton; @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); mText1 = (TextView) findViewById(R.id.myText2); mText1.setText( "文件路径：\n" + uploadFile); mText2 = (TextView) findViewById(R.id.myText3); mText2.setText( "上传网址：\n" + actionUrl); /* 设置mButton的onClick事件处理 */ mButton = (Button) findViewById(R.id.myButton); mButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { uploadFile(actionUrl); } }); } /* 上传文件至Server，uploadUrl：接收文件的处理页面 */ private void uploadFile(String uploadUrl) { String end = "\r\n" ; String twoHyphens = "--" ; String boundary = "******" ; try { URL url = new URL(uploadUrl); HttpURLConnection httpURLConnection = (HttpURLConnection) url .openConnection(); // 设置每次传输的流大小，可以有效防止手机因为内存不足崩溃 // 此方法用于在预先不知道内容长度时启用没有进行内部缓冲的 HTTP 请求正文的流。 httpURLConnection.setChunkedStreamingMode( 128 * 1024 ); // 128K // 允许输入输出流 httpURLConnection.setDoInput( true ); httpURLConnection.setDoOutput( true ); httpURLConnection.setUseCaches( false ); // 使用POST方法 httpURLConnection.setRequestMethod( "POST" ); httpURLConnection.setRequestProperty( "Connection" , "Keep-Alive" ); httpURLConnection.setRequestProperty( "Charset" , "UTF-8" ); httpURLConnection.setRequestProperty( "Content-Type" , "multipart/form-data;boundary=" + boundary); DataOutputStream dos = new DataOutputStream( httpURLConnection.getOutputStream()); dos.writeBytes(twoHyphens + boundary + end); dos.writeBytes( "Content-Disposition: form-data; name=\"uploadedfile\"; filename=\"" + srcPath.substring(srcPath.lastIndexOf( "/" ) + 1 ) + "\"" + end); dos.writeBytes(end); FileInputStream fis = new FileInputStream(srcPath); byte [] buffer = new byte [ 8192 ]; // 8k int count = 0 ; // 读取文件 while ((count = fis.read(buffer)) != - 1 ) { dos.write(buffer, 0 , count); } fis.close(); dos.writeBytes(end); dos.writeBytes(twoHyphens + boundary + twoHyphens + end); dos.flush(); InputStream is = httpURLConnection.getInputStream(); InputStreamReader isr = new InputStreamReader(is, "utf-8" ); BufferedReader br = new BufferedReader(isr); String result = br.readLine(); Toast.makeText( this , result, Toast.LENGTH_LONG).show(); dos.close(); is.close(); } catch (Exception e) { e.printStackTrace(); setTitle(e.getMessage()); } } }

在AndroidManifest.xml文件里添加网络访问权限：

<         uses-permission         android:name         =         "android.permission.INTERNET"         />

运行结果：

以上已经能够实现文件上传，但没有上传进度。这次在之前的基础上添加进度显示，Java代码如下所示：

package com.lenovo.uptest; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.File; import java.io.FileInputStream; import java.net.HttpURLConnection; import java.net.URL; import android.app.Activity; import android.app.AlertDialog; import android.app.ProgressDialog; import android.content.DialogInterface; import android.os.AsyncTask; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.TextView; public class UploadtestActivity extends Activity { /** Called when the activity is first created. */ /** * Upload file to web server with progress status, client: android; * server:php * **/ private TextView mtv1 = null ; private TextView mtv2 = null ; private Button bupload = null ; private String uploadFile = "/sdcard/testimg.jpg" ; private String actionUrl = "http://10.100.1.208/receive_file.php" ; @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); mtv1 = (TextView) findViewById(R.id.mtv1); mtv1.setText( "文件路径：\n" + uploadFile); mtv2 = (TextView) findViewById(R.id.mtv2); mtv2.setText( "上传地址：\n" + actionUrl); bupload = (Button) findViewById(R.id.bupload); bupload.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub FileUploadTask fileuploadtask = new FileUploadTask(); fileuploadtask.execute(); } }); } // show Dialog method private void showDialog(String mess) { new AlertDialog.Builder(UploadtestActivity. this ).setTitle( "Message" ) .setMessage(mess) .setNegativeButton( "确定" , new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }).show(); } class FileUploadTask extends AsyncTask<Object, Integer, Void> { private ProgressDialog dialog = null ; HttpURLConnection connection = null ; DataOutputStream outputStream = null ; DataInputStream inputStream = null ; //the file path to upload String pathToOurFile = "/sdcard/testimg.jpg" ; //the server address to process uploaded file String urlServer = "http://10.100.1.208/receive_file.php" ; String lineEnd = "\r\n" ; String twoHyphens = "--" ; String boundary = "*****" ; File uploadFile = new File(pathToOurFile); long totalSize = uploadFile.length(); // Get size of file, bytes @Override protected void onPreExecute() { dialog = new ProgressDialog(UploadtestActivity. this ); dialog.setMessage( "正在上传..." ); dialog.setIndeterminate( false ); dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); dialog.setProgress( 0 ); dialog.show(); } @Override protected Void doInBackground(Object... arg0) { long length = 0 ; int progress; int bytesRead, bytesAvailable, bufferSize; byte [] buffer; int maxBufferSize = 256 * 1024 ; // 256KB try { FileInputStream fileInputStream = new FileInputStream( new File( pathToOurFile)); URL url = new URL(urlServer); connection = (HttpURLConnection) url.openConnection(); // Set size of every block for post connection.setChunkedStreamingMode( 256 * 1024 ); // 256KB // Allow Inputs & Outputs connection.setDoInput( true ); connection.setDoOutput( true ); connection.setUseCaches( false ); // Enable POST method connection.setRequestMethod( "POST" ); connection.setRequestProperty( "Connection" , "Keep-Alive" ); connection.setRequestProperty( "Charset" , "UTF-8" ); connection.setRequestProperty( "Content-Type" , "multipart/form-data;boundary=" + boundary); outputStream = new DataOutputStream( connection.getOutputStream()); outputStream.writeBytes(twoHyphens + boundary + lineEnd); outputStream .writeBytes( "Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + pathToOurFile + "\"" + lineEnd); outputStream.writeBytes(lineEnd); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); buffer = new byte [bufferSize]; // Read file bytesRead = fileInputStream.read(buffer, 0 , bufferSize); while (bytesRead > 0 ) { outputStream.write(buffer, 0 , bufferSize); length += bufferSize; progress = ( int ) ((length * 100 ) / totalSize); publishProgress(progress); bytesAvailable = fileInputStream.available(); bufferSize = Math.min(bytesAvailable, maxBufferSize); bytesRead = fileInputStream.read(buffer, 0 , bufferSize); } outputStream.writeBytes(lineEnd); outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd); publishProgress( 100 ); // Responses from the server (code and message) int serverResponseCode = connection.getResponseCode(); String serverResponseMessage = connection.getResponseMessage(); /* 将Response显示于Dialog */ // Toast toast = Toast.makeText(UploadtestActivity.this, "" // + serverResponseMessage.toString().trim(), // Toast.LENGTH_LONG); // showDialog(serverResponseMessage.toString().trim()); /* 取得Response内容 */ // InputStream is = connection.getInputStream(); // int ch; // StringBuffer sbf = new StringBuffer(); // while ((ch = is.read()) != -1) { // sbf.append((char) ch); // } // // showDialog(sbf.toString().trim()); fileInputStream.close(); outputStream.flush(); outputStream.close(); } catch (Exception ex) { // Exception handling // showDialog("" + ex); // Toast toast = Toast.makeText(UploadtestActivity.this, "" + // ex, // Toast.LENGTH_LONG); } return null ; } @Override protected void onProgressUpdate(Integer... progress) { dialog.setProgress(progress[ 0 ]); } @Override protected void onPostExecute(Void result) { try { dialog.dismiss(); // TODO Auto-generated method stub } catch (Exception e) { } } } }

       服务器端仍然和之前的一样。

        这里使用了AsyncTask，它使创建需要与用户界面交互的长时间运行的任务变得更简单，适用于简单的异步处理，不需要借助线程和Handler即可实现。         AsyncTask是抽象类.AsyncTask定义了三种泛型类型 Params，Progress和Result。          Params 启动任务执行的输入参数，比如HTTP请求的URL。          Progress 后台任务执行的百分比。          Result 后台执行任务最终返回的结果，比如String。          AsyncTask的执行分为四个步骤，每一步都对应一个回调方法，这些方法不应该由应用程序调用，开发者需要做的就是实现这些方法。          1) 子类化AsyncTask          2) 实现AsyncTask中定义的下面一个或几个方法          onPreExecute(), 该方法将在执行实际的后台操作前被UI thread调用。可以在该方法中做一些准备工作，如在界面上显示一个进度条。          doInBackground(Params...), 将在onPreExecute 方法执行后马上执行，该方法运行在后台线程中。这里将主要负责执行那些很耗时的后台计算工作。可以调用 publishProgress方法来更新实时的任务进度。该方法是抽象方法，子类必须实现。         onProgressUpdate(Progress...),在publishProgress方法被调用后，UI thread将调用这个方法从而在界面上展示任务的进展情况，例如通过一个进度条进行展示。         onPostExecute(Result), 在doInBackground 执行完成后，onPostExecute 方法将被UI thread调用，后台的计算结果将通过该方法传递到UI thread.         为了正确的使用AsyncTask类，以下是几条必须遵守的准则：          1) Task的实例必须在UI thread中创建          2) execute方法必须在UI thread中调用          3) 不要手动的调用onPreExecute(), onPostExecute(Result)，doInBackground(Params...), onProgressUpdate(Progress...)这几个方法         4) 该task只能被执行一次，否则多次调用时将会出现异常          doInBackground方法和onPostExecute的参数必须对应，这两个参数在AsyncTask声明的泛型参数列表中指定，第一个为 doInBackground接受的参数，第二个为显示进度的参数，第三个为doInBackground返回和onPostExecute传入的参数。

运行结果如下：