Android 我能'；t从assest复制xml文件

我想复制数据目录中的xml文件。我这样做了，但下面的代码无法复制数据目录中的xml文件

private void copyAsset(){

    AssetManager assetmanager=getAssets();

    InputStream in=null;



    OutputStream out=null;
    String filename="deathtrack.xml";
    try {
        in=assetmanager.open(filename);
        out=new FileOutputStream(Environment.getDataDirectory().toString()+"/" +filename);
        copyFile(in, out);
        in.close();
        in = null;
        out.flush();
        out.close();
        out = null;
    }
    catch (IOException e)
    {
        Log. e ( "tag" , "Failed to copy asset file: " , e);
    }
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{Writer writer = new StringWriter();
    char[] buffer = new char[1024];
    Reader reader = new BufferedReader(
        new InputStreamReader(in, "UTF-8" ));


    int n;
    while ((n= reader.read(buffer)) != -1)
    {
        writer.write(buffer, 0, n);
    }

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如果有人知道怎么做？请帮助我。

我不明白你为什么要用 Writer-Writer=新的StringWriter（）

copyFile功能很简单：

     private void copyFile(InputStream in, OutputStream out) throws IOException {
         byte[] buffer = new byte[1024];
         int read;
         while((read = in.read(buffer)) != -1){
           out.write(buffer, 0, read);
         }
     }

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你遇到了什么问题？日志中是否有错误，或者是否有IOException？