运行结果：没有找到该文件！
list.txt (系统找不到指定的文件。)
    at (Native Method)
    at (Unknown Source)
    at (Unknown Source)
    at (Unknown Source)
    at ReadList.main(ReadList.java:20)
Exception in thread "main" java.lang.NullPointerException
    at (Unknown Source)
    at FileCpy.copyDir(FileCpy.java:33)
    at ReadList.main(ReadList.java:32)



import
import
import
import
import java.util.ArrayList;

public class ReadList{

    public static ArrayList<FileCpy> fileList;
    private static String src;
    private static String bak;

    public static void main(String[] args) throws IOException{
        BufferedReader br = null;

        //捕捉异常，如果list.txt不存在，则执行catch,输出“没有找到该文件！”
        try {
                br = new BufferedReader(new FileReader("list.txt"));
                String line = "";
               
                while ((line = br.readLine()) != null) {
                    System.out.println(line);
                }
                reader("list.txt");
            } catch (FileNotFoundException e){
                e.printStackTrace();
                System.out.println("没有找到该文件！");
            }
   
        if(FileCpy.copyDir(src, bak)){
            for(FileCpy fil:fileList){
                fil.copyFile();
            }
        } else{
            System.out.println("不能找到src目录");
        }
    }

    //读取文件中的内容，将每行的文件作为动态数组中的元素
    public static void reader(String fileName) throws IOException{
        FileReader file=new FileReader(fileName);
        BufferedReader br=new BufferedReader(file);
        fileList=new ArrayList<FileCpy>();
        while(br.readLine()!=null){
            FileCpy file1=new FileCpy(br.readLine());
            fileList.add(file1);
        }
    }


}



import *;

public class FileCpy {
    private String fileName;
    private String bak;
    public FileCpy(String name){
        setFileName(name);
    }
    public void setFileName(String fileName) {
        this.fileName = fileName;
    }
    public String getFileName() {
        return fileName;
    }
    //复制文件
    public void copyFile()throws IOException{
        File first=new File(fileName);
        File second=new File(bak,fileName);
        if(!first.exists()) {
            System.out.println("该文件不存在！");
        } else{
            FileInputStream fis = new FileInputStream(first);
            byte[] buff = new byte[1024];
            FileOutputStream fos = new FileOutputStream(second);
            while (fis.read(buff) != -1) {
                fos.write(buff);
            }
        }
    }
    //判断src目录是否存在，建立bak目录,返回是否存在src
    public static boolean copyDir(String src,String bak){
        File srcDir=new File(src);
        File bakDir=new File(bak);
         if(srcDir.exists()){
            if(!bakDir.exists()){
                bakDir.mkdir();
            }
        }
         return true;
    }
}

找错误太痛苦，看英语更痛苦，我还是会找，也希望你能帮我

解决了，谢谢

谢谢