檔案下載類 HttpDownloader,記憶體卡操作類 FileUtils
阿新 • • 發佈：2018-12-30
download.java
package zlj.download;
import zlj.utils.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 {
/** Called when the activity is first created. */
private Button downloadText = null;
private Button downloadMp3 = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
downloadText = (Button)findViewById(R.id.downloadText);
downloadText.setOnClickListener(new downloadTextClicklistener());
downloadMp3 = (Button)findViewById(R.id.downloadMp3);
downloadMp3.setOnClickListener(new downloadMp3Clicklistener());
}
class downloadTextClicklistener implements OnClickListener{
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
HttpDownloader httpDownloader = new HttpDownloader();
//http://www.lrc123.com/download/lrc/86547-30.aspx ,流星
System.out.println("開始下載文字");
String lrc = httpDownloader.download("http://115.156.228.135:8080/Mp3/liuxing.lrc");//localhost手機無法識別
// String lrc1 = httpDownloader.download("http://www.lrc123.com/download/lrc/86547-30.aspx");
System.out.println("lrc->" + lrc);
// System.out.println("lrc1->" + lrc1);
}
}
class downloadMp3Clicklistener implements OnClickListener{
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
HttpDownloader httpDownloader = new HttpDownloader();
System.out.println("開始下載Mp3");
int result = httpDownloader.downloadFile("http://115.156.228.135:8080/Mp3/liuxing.mp3","Mp3/","liuxing.mp3");
System.out.println(result);
}
}
}
HttpDownloader.java
1 package mars.utils; 2 3 import java.io.BufferedReader; 4 import java.io.File; 5 import java.io.IOException; 6 import java.io.InputStream; 7 import java.io.InputStreamReader; 8 import java.net.HttpURLConnection; 9 import java.net.MalformedURLException; 10 import java.net.URL;11 12 13 public class HttpDownloader { 14 private URL url = null; 15 16 /** 17 * 根據URL下載檔案，前提是這個檔案當中的內容是文字，函式的返回值就是檔案當中的內容 18 * 1.建立一個URL物件 19 * 2.通過URL物件，建立一個HttpURLConnection物件 20 * 3.得到InputStram 21 * 4.從InputStream當中讀取資料 22 * @param urlStr 23 * @return 24 */ 25 public String download(String urlStr) { 26 StringBuffer sb = new StringBuffer(); 27 String line = null; 28 BufferedReader buffer = null; 29 try { 30 // 建立一個URL物件 31 url = new URL(urlStr); 32 // 建立一個Http連線 33 HttpURLConnection urlConn = (HttpURLConnection) url 34 .openConnection(); 35 // 使用IO流讀取資料 36 buffer = new BufferedReader(new InputStreamReader(urlConn 37 .getInputStream())); 38 while ((line = buffer.readLine()) != null) { 39 sb.append(line); 40 } 41 } catch (Exception e) { 42 e.printStackTrace(); 43 } finally { 44 try { 45 buffer.close(); 46 } catch (Exception e) { 47 e.printStackTrace(); 48 } 49 } 50 return sb.toString(); 51 } 52 53 /** 54 * 該函式返回整形 -1：代表下載檔案出錯 0：代表下載檔案成功 1：代表檔案已經存在 55 */ 56 public int downloadFile(String urlStr, String path, String fileName) {//Mark,下載檔案 57 InputStream inputStream = null; 58 try { 59 FileUtils fileUtils = new FileUtils(); 60 61 if (fileUtils.isFileExist(path + fileName)) { 62 return 1; 63 } else { 64 inputStream = getInputStreamFromUrl(urlStr); 65 File resultFile = fileUtils.write2SDFromInput(path,fileName, inputStream); 66 if (resultFile == null) { 67 return -1; 68 } 69 } 70 } catch (Exception e) { 71 e.printStackTrace(); 72 return -1; 73 } finally { 74 try { 75 inputStream.close(); 76 } catch (Exception e) { 77 e.printStackTrace(); 78 } 79 } 80 return 0; 81 } 82 83 /** 84 * 根據URL得到輸入流 85 * 86 * @param urlStr 87 * @return 88 * @throws MalformedURLException 89 * @throws IOException 90 */ 91 public InputStream getInputStreamFromUrl(String urlStr) 92 throws MalformedURLException, IOException { 93 url = new URL(urlStr); 94 HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); 95 InputStream inputStream = urlConn.getInputStream(); 96 return inputStream; 97 } 98 }
FileUtils.java
1 package mars.utils; 2 3 import java.io.File; 4 import java.io.FileOutputStream; 5 import java.io.IOException; 6 import java.io.InputStream; 7 import java.io.OutputStream; 8 9 import android.os.Environment; 10 11 public class FileUtils { 12 private String SDPATH; 13 14 public String getSDPATH() { 15 return SDPATH; 16 } 17 public FileUtils() { 18 //得到當前外部儲存裝置的目錄 19 // /SDCARD 20 SDPATH = Environment.getExternalStorageDirectory() + "/"; 21 } 22 /** 23 * 在SD卡上建立檔案 24 * 25 * @throws IOException 26 */ 27 public File creatSDFile(String fileName) throws IOException { 28 File file = new File(SDPATH + fileName); 29 file.createNewFile(); 30 return file; 31 } 32 33 /** 34 * 在SD卡上建立目錄 35 * 36 * @param dirName 37 */ 38 public File creatSDDir(String dirName) { 39 File dir = new File(SDPATH + dirName); 40 dir.mkdirs(); 41 return dir; 42 } 43 44 /** 45 * 判斷SD卡上的資料夾是否存在 46 */ 47 public boolean isFileExist(String fileName){ 48 File file = new File(SDPATH + fileName); 49 return file.exists(); 50 } 51 52 /** 53 * 將一個InputStream裡面的資料寫入到SD卡中 54 */ 55 public File write2SDFromInput(String path,String fileName,InputStream input){ 56 File file = null; 57 OutputStream output = null; 58 try{ 59 creatSDDir(path); 60 file = creatSDFile(path + fileName); 61 output = new FileOutputStream(file); 62 byte buffer [] = new byte[4 * 1024]; 63 while((input.read(buffer)) != -1){ 64 output.write(buffer); 65 } 66 output.flush(); 67 } 68 catch(Exception e){ 69 e.printStackTrace(); 70 } 71 finally{ 72 try{ 73 output.close(); 74 } 75 catch(Exception e){ 76 e.printStackTrace(); 77 } 78 } 79 return file; 80 } 81 82 }
main.xml
<?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"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<Button
android:id="@+id/downloadText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="下載文字"
/>
<Button
android:id="@+id/downloadMp3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="下載Mp3"
/>
</LinearLayout>
AndroidManifest.xml
1 <?xml version="1.0" encoding="utf-8"?> 2 <manifest xmlns:android="http://schemas.android.com/apk/res/android" 3 package="mars.download" 4 android:versionCode="1" 5 android:versionName="1.0"> 6 <application android:icon="@drawable/icon" android:label="@string/app_name"> 7 <activity android:name=".Download" 8 android:label="@string/app_name"> 9 <intent-filter> 10 <action android:name="android.intent.action.MAIN" /> 11 <category android:name="android.intent.category.LAUNCHER" /> 12 </intent-filter> 13 </activity> 14 </application> 15 <uses-sdk android:minSdkVersion="4" /> 16 <uses-permission android:name="android.permission.INTERNET"/> 17 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 18 </manifest>