Android 上载文件及写入SD卡

Android 下载文件及写入SD卡,实例代码

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<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    ><Button  	android:id="@+id/downloadTxt"    android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="下载文本文件"    /><Button  	android:id="@+id/downloadMp3"    android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="下载MP3文件"    /></LinearLayout>

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<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.learning.example"      android:versionCode="1"      android:versionName="1.0">    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".Download"                  android:label="@string/app_name">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application>    <uses-sdk android:minSdkVersion="8" /><!-- 访问网络和操作SD卡 加入的两个权限配置--><uses-permission android:name="android.permission.INTERNET"/><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/></manifest> 

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package com.learning.example.util;import java.io.BufferedReader;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;public class HttpDownloader {		private URL url = null; 		/**	 * 根据URL下载文件,前提是这个文件当中的内容是文本,函数的返回值就是文本当中的内容	 * 1.创建一个URL对象	 * 2.通过URL对象,创建一个HttpURLConnection对象	 * 3.得到InputStream	 * 4.从InputStream当中读取数据	 * @param urlStr	 * @return	 */	public String download(String urlStr){		StringBuffer sb = new StringBuffer();		String line = null;		BufferedReader buffer = null;		try {			url = new URL(urlStr);			HttpURLConnection urlConn = (HttpURLConnection)url.openConnection();			buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));			while( (line = buffer.readLine()) != null){				sb.append(line);			}					} 		catch (Exception e) {			e.printStackTrace();		}		finally{			try {				buffer.close();			} catch (IOException e) {				e.printStackTrace();			}		}		return sb.toString();	}	/**	 * 	 * @param urlStr	 * @param path	 * @param fileName	 * @return 	 * 		-1:文件下载出错	 * 		 0:文件下载成功	 * 		 1:文件已经存在	 */	public int downFile(String urlStr, String path, String fileName){		InputStream inputStream = null;		try {			FileUtils fileUtils = new FileUtils();						if(fileUtils.isFileExist(path + fileName)){				return 1;			} else {				inputStream = getInputStreamFromURL(urlStr);				File resultFile = fileUtils.write2SDFromInput(path, fileName, inputStream);				if(resultFile == null){					return -1;				}			}		} 		catch (Exception e) {			e.printStackTrace();			return -1;		}		finally{			try {				inputStream.close();			} catch (IOException e) {				e.printStackTrace();			}		}		return 0;	}		/**	 * 根据URL得到输入流	 * @param urlStr	 * @return	 */	public InputStream getInputStreamFromURL(String urlStr) {		HttpURLConnection urlConn = null;		InputStream inputStream = null;		try {			url = new URL(urlStr);			urlConn = (HttpURLConnection)url.openConnection();			inputStream = urlConn.getInputStream();					} catch (MalformedURLException e) {			e.printStackTrace();		} catch (IOException e) {			e.printStackTrace();		}				return inputStream;	}}

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package com.learning.example.util;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import android.os.Environment;public class FileUtils {	private String SDPATH;		private int FILESIZE = 4 * 1024; 		public String getSDPATH(){		return SDPATH;	}		public FileUtils(){		//得到当前外部存储设备的目录( /SDCARD )		SDPATH = Environment.getExternalStorageDirectory() + "/";	}		/**	 * 在SD卡上创建文件	 * @param fileName	 * @return	 * @throws IOException	 */	public File createSDFile(String fileName) throws IOException{		File file = new File(SDPATH + fileName);		file.createNewFile();		return file;	}		/**	 * 在SD卡上创建目录	 * @param dirName	 * @return	 */	public File createSDDir(String dirName){		File dir = new File(SDPATH + dirName);		dir.mkdir();		return dir;	}		/**	 * 判断SD卡上的文件夹是否存在	 * @param fileName	 * @return	 */	public boolean isFileExist(String fileName){		File file = new File(SDPATH + fileName);		return file.exists();	}		/**	 * 将一个InputStream里面的数据写入到SD卡中	 * @param path	 * @param fileName	 * @param input	 * @return	 */	public File write2SDFromInput(String path,String fileName,InputStream input){		File file = null;		OutputStream output = null;		try {			createSDDir(path);			file = createSDFile(path + fileName);			output = new FileOutputStream(file);			byte[] buffer = new byte[FILESIZE];			while((input.read(buffer)) != -1){				output.write(buffer);			}			output.flush();		} 		catch (Exception e) {			e.printStackTrace();		}		finally{			try {				output.close();			} catch (IOException e) {				e.printStackTrace();			}		}		return file;	}}

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package com.learning.example;import com.learning.example.util.HttpDownloader;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class Download extends Activity {	private Button downlaodTxtButton ;	private Button downlaodMP3Button ;	    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        downlaodTxtButton = (Button)findViewById(R.id.downloadTxt);        downlaodTxtButton.setOnClickListener(new DownloadTxtListener());                downlaodMP3Button = (Button)findViewById(R.id.downloadMp3);        downlaodMP3Button.setOnClickListener(new DownloadMP3Listener());    }        class DownloadTxtListener implements OnClickListener{		@Override		public void onClick(View v) {			HttpDownloader downloader = new HttpDownloader();			String lrc = downloader.download("http://172.16.11.9:8080/test/1.lrc");			System.out.println(lrc);		}    	    }        class DownloadMP3Listener implements OnClickListener{		@Override		public void onClick(View v) {			HttpDownloader downloader = new HttpDownloader();			int result = downloader.downFile("http://172.16.11.9:8080/test/1.mp3", "voa/", "1.map3");			System.out.println(result);		}    	    }}

Notice:访问网络和操作SD卡 记得加入的两个权限配置

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

private int FILESIZE = 4 * 1024; byte[] buffer = new byte[FILESIZE];  while((input.read(buffer)) != -1){      output.write(buffer);  }  output.flush();

private int FILESIZE = 4 * 1024; byte[] buffer = new byte[FILESIZE];  while((input.read(buffer)) != -1){      output.write(buffer);  }  output.flush();

10 楼 zdfeng 2011-10-09  

我喜欢，java看着就是爽，虽然是android，基础，还是java。好风格，好作者。