Android实现上传文件功能的方法

本文所述为一个Android上传文件的源代码，每一步实现过程都备有详尽的注释，思路比较清楚，学习了本例所述上传文件代码之后，你可以应对其它格式文件的上传。实例中主要实现上传文件至Server的方法，允许Input、Output，不使用Cache，使Androiod上传文件变得轻松。

主要功能代码如下：

package com.test;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.app.alertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity {
  
  private String newName="image.jpg";
  private String uploadFile="/data/image.jpg";
  private String actionUrl="http://l27.0.0.1/upload/upload.jsp";
  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);
     
   mButton = (Button) findViewById(R.id.myButton);
   mButton.setonClickListener(new View.onClickListener()
   {
    public void onClick(View v)
    {
     uploadFile();
    }
   });
  }

  
  private void uploadFile()
  {
   String end = "rn";
   String twoHyphens = "--";
   String boundary = "*****";
   try
   {
    URL url =new URL(actionUrl);
    HttpURLConnection con=(HttpURLConnection)url.openConnection();
    
    con.setDoInput(true);
    con.setDoOutput(true);
    con.setUseCaches(false);
    
    con.setRequestMethod("POST");
    
    con.setRequestProperty("Connection", "Keep-Alive");
    con.setRequestProperty("Charset", "UTF-8");
    con.setRequestProperty("Content-Type",
      "multipart/form-data;boundary="+boundary);
    
    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);  

    
    FileInputStream fStream = new FileInputStream(uploadFile);
    
    int bufferSize = 1024;
    byte[] buffer = new byte[bufferSize];

    int length = -1;
    
    while((length = fStream.read(buffer)) != -1)
    {
     
     ds.write(buffer, 0, length);
    }
    ds.writeBytes(end);
    ds.writeBytes(twoHyphens + boundary + twoHyphens + end);

    
    fStream.close();
    ds.flush();

    
    InputStream is = con.getInputStream();
    int ch;
    StringBuffer b =new StringBuffer();
    while( ( ch = is.read() ) != -1 )
    {
     b.append( (char)ch );
    }
    
    showDialog(b.toString().trim());
    
    ds.close();
   }
   catch(Exception e)
   {
    showDialog(""+e);
   }
  }

  
  private void showDialog(String mess)
  {
   new alertDialog.Builder(Main.this).setTitle("Message")
   .setMessage(mess)
   .setNegativeButton("确定",new DialogInterface.onClickListener()
   {
    public void onClick(DialogInterface dialog, int which)
    {     
    }
   })
   .show();
  }
}

读者如果觉得功能不足的话可以对代码进行扩展与完善，使之更加符合自身的应用需求。