我的程序完全按照我想要的方式运行，但是我在控制台中收到错误消息：
线程中的异常＆＃34; main＆＃34; java.lang.IndexOutOfBoundsException：索引： 6，尺寸：6
at java.util.ArrayList.rangeCheck（ArrayList.java:653）
at java.util.ArrayList.get（ArrayList.java:429）
在Kevinmath4.checkAnswers（Kevinmath4.java:152）
在Kevinmath4.main（Kevinmath4.java:39）
以下是代码：
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Kevinmath4 {
static File filename = new File("homework.txt");
static ArrayList<Object> aList = new ArrayList<Object>();
static String homework = "";
static File filename2 = new File("homework2.txt");
static ArrayList<Object> aList2 = new ArrayList<Object>();
static String homework2 = "";
static String answerPass = "";
static ArrayList<Object> aList3 = new ArrayList<Object>();
static final int TOTAL_QUESTIONS = 5;
static String date;
public static void main(String[] args) throws FileNotFoundException {
String initialInput = JOptionPane.showInputDialog(null,
"Enter Add answers / Check answers to continue");
switch (initialInput) {
case "Add answers":
answers("excalibur117", aList, filename);
break;
// Need to store the array permanently
case "Check answers": // Need to make it so it stores array of
// Kevin's answers permanently
clearFile(filename2);
answers("Kevin", aList2, filename2);
readAnswers(filename, aList3);
checkAnswers(aList3, aList2);
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
break;
}
clearFile(filename2);
// exit the program
JOptionPane.showMessageDialog(null,
"Thanks for using this program. Cheers!");
}
public static void answers(String pass, ArrayList<Object> list, File f) {
answerPass = JOptionPane.showInputDialog(null,
"Please enter the password");
// validate user
while (!answerPass.equals(pass)) {
JOptionPane.showMessageDialog(null,
"Incorrect Password. Please try again.");
answerPass = JOptionPane.showInputDialog(null,
"Please enter the password.");
}
// add answers
String final1 = "";
do {
list.clear();
// validate the date of the answers
date = JOptionPane.showInputDialog(null,
"Enter the date of the desired" + " answers (MM/DD/YY)");
// add your answers
enterAnswers(date, list, f);
// verify the answers
final1 = JOptionPane.showInputDialog(null, "Is this correct: "
+ list.get(1) + " " + list.get(2) + " " + list.get(3) + " "
+ list.get(4) + " " + list.get(5) + "? (Yes/No)");
} while (final1.charAt(0) == 'n' || final1.charAt(0) == 'N');
}
public static void enterAnswers(String options, ArrayList<Object> list,
File f) {
do {
boolean valid = false;
list.add(date);
for (int i = 0; i < 5; i++) {
while (!valid) {
homework = JOptionPane
.showInputDialog("Please enter your answer for question "
+ (i + 1));
if (!homework.isEmpty())
valid = true;
}
list.add(homework);
valid = false;
}
writeFile(f, list); // write the answers to a file
break;
} while (!homework.isEmpty());
}
public static void writeFile(File filename, ArrayList<Object> list) {
try {
FileWriter fw = new FileWriter(filename, true);
Writer output = new BufferedWriter(fw);
for (int j = 0; j < list.size(); j++) {
output.write(list.get(j) + "\n");
}
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null,
"Oops! I cannot create that file.");
}
}
public static void clearFile(File filename) {
try {
FileWriter fw = new FileWriter(filename, false);
Writer output = new BufferedWriter(fw);
output.write("");
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null,
"Oops! I cannot create that file.");
}
}
public static void checkAnswers(ArrayList<Object> a, ArrayList<Object> b) {
int i = 1; // counter variable
int j = a.indexOf(date);
for (Object obj : a) { // iterate through any list
for (int k = (j + 1); k < (j + 6); k++) {
if (obj.getClass() == String.class) { // find if it's a
// string
if (!a.get(k).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + (i)
+ " is wrong.");
}
}
if (obj.getClass() == Double.class) { // or a double
if (!a.get(k).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + (i)
+ " is wrong.");
}
}
if (obj.getClass() == Integer.class) { // or an integer
if (!a.get(k).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + (i)
+ " is wrong.");
}
}
i++;
}
}
}
public static void readAnswers(File filename, ArrayList<Object> list)
throws FileNotFoundException {
Scanner s = new Scanner(new File("homework.txt"));
while (s.hasNextLine()) {
list.add(s.nextLine());
}
s.close();
}
}
我做错了什么？
答案 0 :(得分：1)
问题是你的for循环，
for (int k = (j + 1); k < (j + 6); k++) {
当您（盲目地）访问a.get(k)时，您 知道 k < a.size()（如果它== a.size()你是＆＃39 ;得到你发布的例外）。我想你想要，
for (int k = (j + 1); k < a.size(); k++) {
答案 1 :(得分：1)
一般来说，听起来像'＃34;我的代码完成它应该做的事情，然后我得到了一个例外＆＃34;，特别是在学术工作中，通常意味着你已经迭代了一个循环一次太多次了。这种情况通过例外ArrayIndexOutOfBoundsException加强。
考虑数组{a，b，c}。到目前为止，我确定您知道所述数组的第0位的值是＆＃39; a＆＃39;，第1位包含＆＃39; b＆＃39;，第2位包含＆＃39; C＆＃39 ;.如果你在Java中尝试访问这个数组的第3位，你将得到一个ArrayIndexOutOfBoundsException，因为在第3位没有元素，并且数组不长。
我要走出困境，并猜测第152行是这一行：
if (!a.get(k).equals(b.get(i)))
我想猜测当k == 6时a.get（k）被调用，但a只有长度6（这意味着它的最高索引是5）。
我猜测表达式for (int k = (j + 1); k < (j + 6); k++)是罪魁祸首，我猜这个表达式应该是for (int k = (j + 1); k < (j + 5); k++)
希望这有帮助。