如何修复代码中的索引错误?

qni6mghb  于 2021-07-09  发布在  Java
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这个问题在这里已经有了答案

什么是indexoutofboundsexception?我该怎么修[重复](1个答案)
两天前关门了。
此错误位于的indexoutofboundsexception中 System.out.println(hurricane.get(2)); . 我怎样才能解决这个问题,以便打印一个飓风对象?我试过几种不同的方法,但都没有用。我试着给hurricane加上null,但没用。它还说索引2超出了长度2的界限。

import java.util.ArrayList;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
import java.util.Scanner;
public class HurricaneTesterTest

{

  public static void main(String[] args) throws IOException {

    //read data from text file & put in an array
    File fileName = new File("HurricaneData.txt");
    Scanner inFile = new Scanner(fileName);
    int numValues = 0;

    //count number of lines in text file
    while (inFile.hasNextLine()) {
      inFile.nextLine();
      numValues++;
    }
    inFile.close();

    //initialize arrays based on lines counted in text file
    ArrayList < Integer > years = new ArrayList < Integer > ();
    ArrayList < String > months = new ArrayList < String > ();
    ArrayList < Integer > pressures = new ArrayList < Integer > ();
    ArrayList < Double > windSpeeds = new ArrayList < Double > ();
    ArrayList < String > names = new ArrayList < String > ();
    ArrayList < String > Cat1 = new ArrayList < String > ();

    //read and assign data from text file to the arrays
    inFile = new Scanner(fileName);
    int index = 0;
    while (inFile.hasNext()) {
      years.add(inFile.nextInt());
      months.add(inFile.next());
      pressures.add(inFile.nextInt());
      windSpeeds.add(inFile.nextDouble());
      names.add(inFile.next());
      index++;
    }
    inFile.close();

    for (int i = 0; i < windSpeeds.size(); i++) {
      windSpeeds.set(i, windSpeeds.get(i) * 1.151);

      //System.out.println(windSpeeds);
    }

    for (int x = 0; x < windSpeeds.size(); x++) {
      if (windSpeeds.get(x) < 96 && windSpeeds.get(x) > 73) {
        Cat1.add("Category 1");
      }
      if (windSpeeds.get(x) < 111 && windSpeeds.get(x) > 95) {
        Cat1.add("Category 2");
      }
      if (windSpeeds.get(x) < 130 && windSpeeds.get(x) > 110) {
        Cat1.add("Category 3");
      }
      if (windSpeeds.get(x) < 157 && windSpeeds.get(x) > 129) {
        Cat1.add("Category 4");
      }
      if (windSpeeds.get(x) > 156) {
        Cat1.add("Category 5");
      }
    }
    ArrayList < Hurricane > hurricane = new ArrayList < Hurricane > ();

    for (int a = 0; a < hurricane.size(); a++) {
      hurricane.add(null);
    }

    for (int r = 0; r < hurricane.size(); r++) {
      hurricane.add(new Hurricane(years.get(r), names.get(r), months.get(r), Cat1.get(r), pressures.get(r), windSpeeds.get(r)));;
    }
    System.out.println(hurricane.get(2));

  }
}

//create a Hurricane ArrayList using the data above

//user prompted for range of years

//print the data
ttcibm8c

ttcibm8c1#

ArrayList<Hurricane> hurricane = new ArrayList<Hurricane>();

for(int a = 0; a<hurricane.size(); a++){
    hurricane.add(null);
}

for(int r = 0; r<hurricane.size(); r++){
      hurricane.add(new Hurricane(years.get(r),names.get(r),months.get(r),Cat1.get(r),pressures.get(r), windSpeeds.get(r)));;
}

根据这些行,您没有向列表添加任何内容,因为它是空的。请尝试以下操作:

ArrayList<Hurricane> hurricane = new ArrayList<Hurricane>();

for(int r = 0; r<years.size(); r++){
      hurricane.add(new Hurricane(years.get(r),names.get(r),months.get(r),Cat1.get(r),pressures.get(r), windSpeeds.get(r)));;
}

对你来说应该有用。您可能会遇到cat1的问题,因为它看起来像是块具有错误的范围比较:cat1(73-96),cat2(95-111)-重叠。

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