代码正在抛出IndexOutOfBoundsExc的？[重复]

Question

有人能告诉我为什么这个代码不起作用吗？它抛出IndexOutOfBoundsException。

package blok6afvink6;

/**
 * 
 */

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Scanner;

public class Blok6afvink6 {

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

        //1st, use Scanner to readin all sequence names and sequences;
        //create two arrayList to store sequence names and sequences;
        ArrayList<String> name = new ArrayList<String>();
        ArrayList<String> sequence = new ArrayList<String>();

        Scanner ScanLine = new Scanner(new FileReader("OverlapGraph.txt"));
        String seq = "";
        while (ScanLine.hasNextLine()) {
            String temp = ScanLine.nextLine();
            if (temp.charAt(0) == '>') {
                sequence.add(seq);
                name.add(temp.substring(1));
                seq = "";
            } else {
                seq += temp;
            }
        }

        ScanLine.close();
        sequence.remove(0);
        sequence.add(seq);

        //naam en seq printen
        int Len = name.size();
        for (int i = 0; i < Len; i++) {
            System.out.println(name.get(i) + ": " + sequence.get(i));
        }
        //3rd, connect all sequences with O3 overlap, put the linked-names into a new string ArrayList
        ArrayList<String> overLaps = linkOverlaps(name, sequence);

        System.out.println("\nPrintout results:");
        for (int i = 0; i < overLaps.size(); i++) {
            System.out.println(overLaps.get(i));
        }
    }

    private static ArrayList<String> linkOverlaps(ArrayList<String> name, ArrayList<String> sequence) {
        ArrayList<String> overLap = new ArrayList<String>();
        //int size = name.size();
        for (int i = 0; i < name.size(); i++) {
            int Len1 = sequence.get(i).length();

            for (int j = 0; j < name.size(); j++) {
                if (i != j && sequence.get(i).substring(Len1 - 3).equals(sequence.get(j).substring(0, 3))) {
                    String linked = name.get(i) + " " + name.get(j);
                    overLap.add(linked);
                }
            }
        }
        return overLap;
    }

}

错误：

Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
    at java.util.ArrayList.rangeCheck(ArrayList.java:653)
    at java.util.ArrayList.remove(ArrayList.java:492)
    at blok6afvink6.Blok6afvink6.main(Blok6afvink6.java:36)

Answer 1

仔细查看错误消息：

Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

似乎您的某个集合的大小为0。如果是这样，那将导致此异常，因为您在尝试访问集合之前并不总是检查以确保集合确实有任何项目。

特别检查序列。

Answer 2

尝试

if(sequence.size() > 0) {
    sequence.remove(0);
}

Answer 3

异常中引用的第 36 行似乎是：

sequence.remove(0);

只有当列表为空时，此异常才能失败。

所以我们必须假设＜code＞序列。添加（seq）从未被调用。

如果没有问题，您可以先检查是否为空：

if (!sequence.isEmpty()) {
    sequence.remove(0);
}