nullpointerexception问题求助！！！
import java.io.*;public class FileOperation{
public static void main(String args[]){
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
File myfile=new File("Line.txt");
String s;
try{
BufferedWriter bw=new BufferedWriter(new FileWriter(myfile));
while(true){
System.out.println("输入字符串：");
s=br.readLine();
if(s.length()==0) break;
bw.write(s);
bw.newLine();
}
bw.close();
}
catch(IOException e){}
try{
BufferedReader brF=new BufferedReader(new FileReader(myfile));
while(true){
s=brF.readLine();
if(s.length()==0) break;
} }
catch(IOException e){}
}
}
求教大神们此处该如何改，谢谢呀！！
----------------解决方案--------------------------------------------------------
程序代码：
import java.io.*;
public class FileOperation{
public static void main(String args[]){
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
File myfile=new File("Line.txt");
String s;
try{
BufferedWriter bw=new BufferedWriter(new FileWriter(myfile));
while(true){
System.out.println("输入字符串：");
s=br.readLine();
if(s.length()==0) break;
bw.write(s);
bw.newLine();
}
bw.close();
}
catch(IOException e){}
try{
BufferedReader brF=new BufferedReader(new FileReader(myfile));
while(true){
s=brF.readLine();
if(s==null) break;
System.out.println(s);
}
brF.close();
}
catch(IOException e){}
}
}
public class FileOperation{
public static void main(String args[]){
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
File myfile=new File("Line.txt");
String s;
try{
BufferedWriter bw=new BufferedWriter(new FileWriter(myfile));
while(true){
System.out.println("输入字符串：");
s=br.readLine();
if(s.length()==0) break;
bw.write(s);
bw.newLine();
}
bw.close();
}
catch(IOException e){}
try{
BufferedReader brF=new BufferedReader(new FileReader(myfile));
while(true){
s=brF.readLine();
if(s==null) break;
System.out.println(s);
}
brF.close();
}
catch(IOException e){}
}
}
主要是读文件时文件结束判断错误，应该是 if(s==null) break;
----------------解决方案--------------------------------------------------------
回复 2楼 lucky563591
非常感谢，按你的方法确实对的，可是我还是不明白为什么用if(s.length()==0)来判断结束就不行？你能讲讲吗？ ----------------解决方案--------------------------------------------------------
怎么没人回了哦？人气不旺呀
----------------解决方案--------------------------------------------------------
路过
----------------解决方案--------------------------------------------------------