Android Open Source - doubanbook4android File Cache

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License

The source code is released under:

Eclipse Public License - v 1.0 THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE PUBLIC LICENSE ("AGREEMENT"). ANY USE, REPRODUCTION OR DISTRIBUTION OF THE PROGRAM CONSTITUTES RECI...

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Java Source Code

package com.study.doubanbook_for_android.imagedownloader;
/*from ww  w  .j  a  va2 s . c  o  m*/
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;


public class FileCache {
  
  @SuppressWarnings("unused")
  private static final String LOG_TAG = FileCache.class.getSimpleName();
  
  private File cacheDir;
  
  /**
   * @param context
   */
  public FileCache(Context context) {
    cacheDir = context.getExternalCacheDir();
    if (cacheDir == null)
      cacheDir = context.getCacheDir();
    ensureDirExists(cacheDir);
  }
  
  public FileCache(File cacheDir) {
    this.cacheDir = cacheDir;
    ensureDirExists(cacheDir);
  }
  
  
  protected void ensureDirExists(File cacheDir) {
    if(!cacheDir.exists()) {
      cacheDir.mkdir();
    }
  }

  /**
   * @param url
   * @param bitmap
   */
  public void addToFileCache(String url, InputStream inputStream) {
    OutputStream outputStream = null;
    try {
      outputStream = new FileOutputStream(getFromFileCache(url));
      copyStream(inputStream, outputStream);
    } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } finally {
      if(outputStream != null) {
        try {
          outputStream.close();
        } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }
      }
    }
  }
  
  public File getFromFileCache(String url) {
    String fileName = urlToFileName(url);
    File file = new File(cacheDir, fileName);
    return file;
  }
  
  /**
   * ??????
   */
  public void clearCache() {
    File[] files=cacheDir.listFiles();
        if(files==null)
            return;
        for(File f:files)
            f.delete();
  }
  
  
  /**
   * 
   * @param url
   * @return
   */
  private String urlToFileName(String url) {
    return String.valueOf(url.hashCode());
  }
  
  private void copyStream(InputStream is, OutputStream os){
        final int buffer_size=1024;
        try
        {
            byte[] bytes=new byte[buffer_size];
            for(;;)
            {
              int count=is.read(bytes, 0, buffer_size);
              if(count==-1)
                  break;
              os.write(bytes, 0, count);
            }
        }
        catch(Exception ex){}
    }


}

Java Source Code List