java中实现文件复制的方法

路径：
String oldpath = "/sdcard/youku/HyteraAppStore.apk";
String newpath = "/sdcard/youku/youku_vip_logger/HyteraAppStore.apk";

复制方法：

public void copyFile(String oldPath, String newPath) {
   
    try {
        int bytesum = 0;
        int byteread = 0;
        File oldfile = new File(oldPath);
        if (oldfile.exists()) { //文件存在时
            InputStream inStream = new FileInputStream(oldPath); //读入原文件
            FileOutputStream fs = new FileOutputStream(newPath);
            byte[] buffer = new byte[1444];
            int length;
            while ( (byteread = inStream.read(buffer)) != -1) {
                bytesum += byteread; //字节数 文件大小
                System.out.println(bytesum);
                Log.d("pppp","bytesum====== " + bytesum);
                fs.write(buffer, 0, byteread);
            }
            inStream.close();
            Log.d("pppp","======success=====");
        }
    }
    catch (Exception e) {
        System.out.println("复制单个文件操作出错");
        e.printStackTrace();
    }
}

 

另附：字符串截取方法（根据需要取字符串中“，”（逗号）后面的字符）

reqResult = "hello,world";
String getSignInfo = reqResult.substring(reqResult.indexOf(",") + 1);