将输出打印到文件 [英] print output to a file

问题描述

这是我在此代码中的代码，可以，但是我无法将输出打印到文件中.您能帮我看看错误在哪里吗

This is my code in this i m gettng o/p ,evrythng if fine but i was unable to print output to a file.Can u help me where was the mistake actually

import java.io.*;
import java.util.*;
public class MainClass {
    public static void main(String[] args) throws Exception {
        int flag=0,cindex=0;;
        String fname=null,first=null,second=null;
        TreeMap tm=new TreeMap();
        File f=new File("D:\\final.txt");
        f.createNewFile();
        PrintWriter pw=new PrintWriter(new FileWriter(f));
        File f1=new File("D:\\trnstons");
        String line=null;
        Map hm2;
        Set s2;
        String lkeys=null,lvalues=null;
        int c=0;
        //BufferedReader br1;

        f1.mkdir();
        String s[]=f1.list();
        //System.out.println("TOTAL COUNT OF FILE::"+s.length);
        int fcount=s.length;
 
        for(String s1:s)
        { 
            File f2=new File("D:\\trnstons\\"+s1);
            BufferedReader br1=new BufferedReader(new FileReader(f2));
            System.out.println( " "+f2.getName());
            //pw.println("===========================FILE NAME IS::====================="+f2.getName());
            line=br1.readLine();
	   
            while(line!=null)
            {
                while((line.equals("SUCCESS")))
                {
                    line=br1.readLine();
                    while(line!=null)
                    {
                        //System.out.println(line);
                        cindex=line.indexOf(",");
                        if(cindex > (-1))
                        {
                            first=line.substring(0,cindex);  
                            second=line.substring(cindex+1); 
                            tm.put(second,first);
                        }
                        //pw.print(line);
                        line=br1.readLine();
		  }
                    ////
                    flag=1;
                    break;
               }
               if(flag==1) 
               break;
	      line=br1.readLine();
	
	  }
	  /////
	  //System.out.println(tm);
      }
  
      //the values in tm are sorted according to values.Now for printing in file as k,v pairs we need to conver to LinkedHashMap
      hm2=new LinkedHashMap(tm);
  
      s2=hm2.entrySet();
      Iterator i=s2.iterator();
      //System.out.println("the values in the tm object are");
      while(i.hasNext())
      {
          Map.Entry me=(Map.Entry)i.next();
          lkeys= (String)me.getKey();/*as the getKey and GetValue returns key and value in the String form,convert in to ArrayList
(it implements RandonAccess(I),so its good at retriveing  rather that any other List  */
          lvalues= (String)me.getValue();
 
          System.out.print(lvalues);
          System.out.print(",");
          System.out.println(lkeys);
          ///trying to print in file 
          pw.print(lvalues);
          pw.print(",");
          pw.println(lkeys);
	 
      } 
   }
}

推荐答案

Java不是我的强项，但我认为您在这里需要额外的\或更少的\ ..

Java isn''t my forte, but I think you either need an extra \ or one less \ here..

or(String s1:s)
        {
            File f2=new File("D:\\trnstons\\"+s1);

(具体来说，最后一个双\\)

(Specifically, the last double \\)

我要说的是，您应该在某一时刻刷新您的编写器并关闭文件编写器...

还要将FileWriter声明为变量:

I would say, that you should at one point flsh your writer and close the filewriter...

Also declare the FileWriter as variable:

// old: PrintWriter pw=new PrintWriter(new FileWriter(f));
FileWriter fw = new FileWriter(f);
PrintWriter pw=new PrintWriter(fw);

// ...

try {
pw.flush();
pw.close();
fw.flush();
fw.close();
} catch (IOException e) {
   System.err.println("Error writing to file:" + e.getMessage());
}

完成对任何文件的写入后，应使用任何文件进行此操作.要在结束写入之前获取未完成的内容，只需使用flush()-Method将内容获取到磁盘...

希望这会有所帮助，
干杯，阿恩特

This should be done with any file, when you finished writing to it. To get unfinished content before ending the write, just use the flush()-Method to get content to Disk...

Hope this helps,
Cheers, Arndt

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