删除txt中不要的字符

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;

public class app {
    public static void main(String[] args) throws IOException{ 
        File file = new File("2.txt");
        Reader fr = new FileReader(file);                    
        Writer fw = new FileWriter("3.txt", false);
        
        int len = fr.read();
        while (-1 != len){
            //System.out.println("=="+len);
            //if(len!=10 && find(len)==1)//全部写成一行
            if(find(len)==1)//取消换行
                fw.write(len);
            len = fr.read();
        }
        
        fw.flush();
        fw.close();
        fr.close();
    }
    public static int find(int x) throws IOException{
        File file = new File("1.txt");
        Reader fr = new FileReader(file);
        int len = fr.read();
        while (-1 != len){
            if(len==x){
                fr.close();
                return 1;
            }
            len = fr.read();
        }
        fr.close();
        return 0;
    }
}