java-文件读/写问题

Question

im having a really weird error: i am using buffered reader (br) and writer(bw) to read from one file - do calculation and write to another file. problem: the first file does not get written to the new file completely. LAst couple of lines get truncated. I tried putting a print statement to see if the file is getting read - and all statements got printed out correctly. I did recheck that i have used bw.close()

Still no clue.

Has any1 every had this problem?

my code snippet is as follows:

private void calculateStats(String input) throws IOException {


   BufferedWriter out = new BufferedWriter(new FileWriter("outputstats.txt"));
   BufferedReader br = new BufferedReader(new FileReader(input));
   int dtime = 0 ;
   double ingress,inMean= 0.0;
   double egress,outMean = 0.0;
   String id, date, newLine = null;
   out.write("interfaceId , I-Mean, I-STD, I-Kurt, I-Skew, E-Mean, E-STD, E-Kurt, E-Skew"+NL);

   DescriptiveStatistics inStats = new DescriptiveStatistics();
   DescriptiveStatistics outStats = new DescriptiveStatistics();
   DescriptiveStatistics inPMean = new DescriptiveStatistics();
   DescriptiveStatistics outPMean = new DescriptiveStatistics();
   DescriptiveStatistics inPStd = new DescriptiveStatistics();
   DescriptiveStatistics outPStd = new DescriptiveStatistics();
   int j = 0;

   while((newLine = br.readLine()) != null){

     //   System.out.println(" new line for statistical output "+newLine);
        StringTokenizer st = new StringTokenizer(newLine, ",");
        for(int i = 0; i<st.countTokens(); i++){
            id = st.nextToken().trim();
            dtime = Integer.parseInt(st.nextToken());
            ingress = Double.parseDouble(st.nextToken().trim());
            egress = Double.parseDouble(st.nextToken().trim());
            date = st.nextToken().trim();

            // set the interface token for easy evaluation

            if(interfaceId.trim().equalsIgnoreCase("no value") || !(interfaceId.trim().equalsIgnoreCase(id))){
                interfaceId = id;
                if(j == 0){
                    out.write(interfaceId + ",");
                    j = 1;//reset j value
                }else{
                inMean = inStats.getMean();
                outMean = outStats.getMean();
                out.write((int) inMean + ","+(int)inStats.getStandardDeviation()+","+
                        (int)inStats.getKurtosis()+ ","+ (int)inStats.getSkewness()+ ","+ (int)outMean + 
                        ","+(int)outStats.getStandardDeviation()+","+(int)outStats.getKurtosis()+","+(int)outStats.getSkewness()+ NL);
                inPMean.addValue(inMean);
                inPStd.addValue(inStats.getStandardDeviation());
                outPMean.addValue(outMean);
                outPStd.addValue(outStats.getStandardDeviation());
                out.write(interfaceId + ",");
                inStats.clear();
                outStats.clear();
                }//end of j initialization
            }

            if(ingress >= 0){
  //                System.out.println("ingress value "+ingress);
                inStats.addValue(ingress);
            }
            if(egress >= 0){
  //                System.out.println("egress value "+egress);
                outStats.addValue(egress);
            }
        }// end of for
   }// end of while

   out.write((int)inMean + "," + (int)outMean);
   out.close();
   br.close();
   percentile(inPMean,inPStd,outPMean,outPStd, "outputstats.txt");

}

private void percentile(DescriptiveStatistics inPMean,
        DescriptiveStatistics inPStd, DescriptiveStatistics outPMean,
        DescriptiveStatistics outPStd, String inputFileName) throws IOException {


        BufferedReader br = new BufferedReader(new FileReader(inputFileName));
        BufferedWriter bw = new BufferedWriter(new FileWriter("outputStatBucket.txt"));
        String newLine = null;
        bw.write(br.readLine()+ NL);
        while((newLine = br.readLine())!= null){
            StringTokenizer st = new StringTokenizer(newLine, ",");
            while(st.hasMoreTokens()){
                System.out.println("newLine "+newLine);
                          bw.write(st.nextToken()+","+calcP(st.nextToken().trim(),inPMean)+"," + calcP(st.nextToken().trim(),inPStd)+
                        ","+st.nextToken().trim()+","+st.nextToken().trim()+","+calcP(st.nextToken().trim(),outPMean)+
                        ","+calcP(st.nextToken().trim(),outPStd)+","+st.nextToken().trim()+","+st.nextToken().trim()+ NL);
            }
        }
        bw.close();
        br.close();
 }
private int calcP(String nextToken, DescriptiveStatistics inPMean) {
    int next = Integer.parseInt(nextToken.trim());
    if(next<= inPMean.getPercentile(25)){
        return 1;
    }else if(next > inPMean.getPercentile(25) && next <=inPMean.getPercentile(50)){
        return 2;
    }else if(next > inPMean.getPercentile(50) && next <=inPMean.getPercentile(75)){
        return 3;
    }else if(next > inPMean.getPercentile(75)){
        return 4;
    }else{
        return 0;
    }
}

Thank you,

Answer 1

如果您得到的是部分输出，则可能的罪魁祸首是您需要调用flush()来确保将写操作写出到文件中。

Answer 2

I ran this (with some modifications) and it works fine for me. Maybe it's writing the final lines and you were looking at outputstats.txt instead of outputStatBucket.txt. The two names are pretty similar and it's a little confusing how the first is used as input for the second.

If that's not it then the code isn't very long at this point so I'd suggest commenting out various parts of the code until only the issue is left (or until it's solved)...