Java 获取文件大小

import java.io.File;

public class FileSize {
    public static long getFileSize(String fileName){
        File file = new File(fileName);
        if (!file.exists() || !file.isFile()){
            System.out.println("文件不存在！！！");
            return -1;
        }
        return  file.length();
    }

    public static void main(String[] args) {
        long size = getFileSize("copyfile");
        System.out.println("文件的大小为："+ size);
    }
}