android文件存儲：直接存儲文件和文件存儲到SDCard

之前我們的內容是存在手機自帶的存儲空間裏的，但是我們知道手機自帶的存儲空間比較小，如果我們要存儲的內容，比如說視頻佔空間很大，我們就必須得將大文件存入SDCard。

1.直接存儲，文件存入/data/data/<package name>/files目錄下

FileService.java   保存文件方法代碼

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//直接存儲文件  public void save(String fileName, String content) throws Exception {         //文件輸出流         FileOutputStream fos;         fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);         fos.write(content.getBytes());         fos.close();     }

單元測試存儲：

1	FileService  service=new FileServie(); service.save("aa.txt", "sfdgdhfh");

存儲成功後的aa文件存到data/data/項目/files下的aa.txt,導出文件查看內容是：sfdgdhfh

 

2.存入SDCard

         用戶輸入文件名及內容點擊保存按鈕存儲到SDCard

        佈局代碼：

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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      xmlns:tools="http://schemas.android.com/tools"      android:layout_width="fill_parent"      android:layout_height="match_parent"      android:orientation="vertical" >                                                                   <TextView          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:text="文件名稱"          tools:context=".MainActivity" />                                                                   <EditText          android:id="@+id/filename"          android:layout_width="fill_parent"          android:layout_height="wrap_content"          android:inputType="text" />                                                                   <TextView          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:text="文件內容" />                                                                   <EditText          android:id="@+id/content"          android:layout_width="fill_parent"          android:layout_height="wrap_content"          android:gravity="top"          android:minLines="4"          android:inputType="textMultiLine" />                                                                   <Button          android:id="@+id/save"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:text="保存"          tools:context=".MainActivity" />                                                               </LinearLayout>

編寫業務類FileService，實現存儲功能saveToSDCard()及讀文件readFile（）

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public class FileService {     private Context context;                                                          public FileService(Context context) {         super();         this.context = context;     }     public void saveToSDcard(String filename, String content) throws IOException{        //創建文件file及得到外部存儲設備絕對路徑        File file=new File(Environment.getExternalStorageDirectory(),filename);        //文件輸出流        FileOutputStream fos=new FileOutputStream(file);        //通過文件輸出流寫入文件內容        fos.write(content.getBytes());        fos.close();     }                                                            // 讀文件     public String readFile(String filename) throws IOException {         FileInputStream fis = context.openFileInput(filename);         int len = 0;         byte[] buffer = new byte[1024];         // 往內存中輸出數據         //另一種輸出方式  StringBuffer sbuffer=new StringBuffer();         ByteArrayOutputStream outstream = new ByteArrayOutputStream();         while ((len = fis.read(buffer)) != -1) {             //sbuffer.append(buffer);             outstream.write(buffer, 0, len);         }         // 得到內存中數據以二進制存放         byte[] s=outstream.toByteArray();              outstream.close();         fis.close();         return new String(s);      }  }

編寫測試類測試存儲方法是否有錯誤

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public class FileServiceTest extends AndroidTestCase {     FileService service = new FileService(getContext());     public void testSaveToSDcard() {         try {             service.saveToSDcard("b.txt", "文件存儲到SDCard,真好");         } catch (IOException e) {             e.printStackTrace();         }     }                                                     public void testReadFile() {         try {             System.out.println(service.readFile("b.txt"));         } catch (IOException e) {             e.printStackTrace();         }                                                            }                                                  }

單元測試應配置一些屬性

1 2	<!-- 單元測試庫的配置 -->          <uses-library android:name="android.test.runner" />

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<!-- 單元測試 -->      <instrumentation          android:name="android.test.InstrumentationTestRunner"          android:targetPackage="cn.bzu.filefro" >      </instrumentation>

Activity代碼

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public class MainActivity extends Activity {     private EditText filename;     private EditText content;     private Button save;     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        filename=(EditText) this.findViewById(R.id.filename);        content=(EditText) this.findViewById(R.id.content);         save=(Button) this.findViewById(R.id.save);         save.setOnClickListener(new View.OnClickListener() {                                                           public void onClick(View v) {                 String file=filename.getText().toString();                 String filecontent=content.getText().toString();                 FileService service=new FileService(MainActivity.this);                 try {                     service.saveToSDcard(file, filecontent);                     System.out.println(service.readFile(file));                     Toast.makeText(MainActivity.this, file+"存儲成功\n內容是："+filecontent, Toast.LENGTH_LONG).show();                                                                       } catch (IOException e) {                     e.printStackTrace();                 }             }         });     } }

效果圖

 

文件存儲到mnt/sdcard/下

導出hello內容是：

大家好，見到你們很高興，嘿嘿。希望以後相處融洽。