我正在尝试使用链接列表从文本文件中整理数据,然后按数字顺序将其重写为另一个预先存在的文本文件。不过,我不断收到空指针异常。有人可以查看我的代码并告诉我缺少什么吗?
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.io.OutputStream;
import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
public class Sort{
public static void main(String[] args){
String infileName=args[0];
String outfileName=args[1];
try{
BufferedReader br=new BufferedReader(new InputStreamReader(new FileInputStream(new File(infileName))));
BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File(outfileName))));
Node linkedList=new Node();
//linkedList.value=Integer.parseInt(br.readLine());
String tempS=br.readLine();
while(tempS!=null){
tempS=br.readLine();
Node tempNode=new Node();
linkedList=tempNode;
tempNode.value=Double.parseDouble(br.readLine());
tempNode.next=linkedList;
bw.write(tempNode.next+"\n");
}
bw.flush();
bw.close();
}catch(IOException ioe){ioe.getMessage();}
}
}
class Node{
Double value;
Node next=null;
}