Android将Assert中文件复制到数据库 Java中将a文件内容复制到b文件

/*
 	 * //path  把address.db这个数据库拷贝到data/data/包名/files/address.db
 	 */
	private void copyDb(String filename) {
//只要你拷贝了一次，我就不要你再拷贝了
		try {
			//在指定的目录创建了 database.db文件
			File file=new File(getFilesDir(), filename);
			if(file.exists()&&file.length()>0){
				//正常了，不需要拷贝了
			    Log.i(TAG,"正常了，不需要拷贝了");
			}else{
				InputStream is=getAssets().open(filename);
				
				FileOutputStream fos=new FileOutputStream(file);
				byte[] buffer=new byte[1024];
				int len=0;
				len=is.read(buffer);
				while(len!=-1){
					fos.write(buffer,0,len);
					len=is.read(buffer);
				}
				is.close();
				fos.close();
				} 
			}
		catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

public class FileInputOutputStreamTest {
	public static void main(String[] args) {
		File af = new File("D:/temp/a.txt");
		File bf = new File("D:/temp/b.txt");
		FileInputStream is = null;
		FileOutputStream os = null;
		if (!bf.exists()) {
			try {
				bf.createNewFile();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		try {
			is = new FileInputStream(af);
			os = new FileOutputStream(bf);
			byte b[] = new byte[1024];
			int len;
			try {
				len = is.read(b);
				while (len != -1) {
					os.write(b, 0, len);
					len = is.read(b);
				}
				System.out.println("文件内容复制成功!");
			} catch (IOException e) {
				e.printStackTrace();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} finally {
			try {
				if (is != null)
					is.close();
				if (os != null)
					os.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

}