java - 关于java中计算耗时的问题

Question

我正在尝试编写一段代码，用于从文件夹中读取 120 个文件并对其执行一些计算。当我调试代码时，它工作正常，但是执行时间超过 20 分钟，我知道这可能是由于代码中的错误造成的。但是，有人可以研究它并提出可能的方法来减少执行时间。如果我需要提供更多信息，请告诉我。谢谢。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;

public class myclass {
  static int total = 1;
  static int r = 0;

  public static void main(String[] args) {

    ArrayList<Double> mysignal = new ArrayList<Double>();
    ArrayList<Double> mylist = new ArrayList<Double>();

    double x;
    double a;
    myclass obj = new myclass();
    String target_dir = "path for folder";
    File dir = new File(target_dir);
    File[] files = dir.listFiles();

    for (File f : files) {
      if (f.isFile()) {
        BufferedReader inputStream = null;

        try {
          inputStream = new BufferedReader(new FileReader(f));
          String line;

          while ((line = inputStream.readLine()) != null) {
            System.out.println(line);
            mysignal.add(Double.valueOf(line));
            total++;

          }
        } catch (IOException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }

        a = obj.funtioneg(mysignal, total);
        mylist.add(r, a);
        System.out.println(mylist.get(r));
        r++;

      }
    }
  }

  public double functioneg(ArrayList<Double> s, int N) {

    ArrayList<Double> y = new ArrayList<Double>();
    double sum = 0, a1 = 0;
    double[] o1 = new double[N - 1];// processed signal

    for (int n = 0; n < counter_main - 1; n++) {
      for (int k = 0; k < 40; k++) {

        if (n - k >= 0) {
          a1 = s.get(n - k);
          sum = sum + (a1 * a1);// energy

        } else
          sum = sum + 0;
      }

      o1[n] = sum;

      sum = 0;

    }
    double sum1 = 0;
    double avg;
    for (int t = 0; t < counter_main - 1; t++) {

      sum1 = sum1 + o1[t];
    }

    avg = sum1 / N - 1;

    return (avg);
  }
}

Answer 1

您需要关闭您的InputStream

读取目录中的每个文件后(在 try - catch block 之后)写入语句:

inputStream.close();