在搜索超过 2 个匹配字母的单词时尝试比较数组列表中的匹配单词时出错

Question

当 builtwordcheck 长度超过 2 个字母时，

ActionListener 给出错误。按下 ActionListener 的要点是打印出列表（单词列表数组文件）中与单词 (builtwordcheck) 匹配且比该单词长的所有单词。我不确定是否需要关于这个词是如何构建的更多上下文，但只是通过点击 String word = word + [letter]

一个一个地添加它的字母

示例：
cat 应该打印出 cats, caterpillar, ...

Exception in thread "AWT-EventQueue-0" java.lang.StringIndexOutOfBoundsException: String index out of range: 2
    at java.base/java.lang.StringLatin1.charAt(StringLatin1.java:48)
    at java.base/java.lang.String.charAt(String.java:1512)
    at MainGame$HintAL.actionPerformed(MainGame.java:117)
    at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972)
    at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2313)
    at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
    at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
    at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
    at java.desktop/java.awt.Component.processMouseEvent(Component.java:6626)
    at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3389)
    at java.desktop/java.awt.Component.processEvent(Component.java:6391)
    at java.desktop/java.awt.Container.processEvent(Container.java:2266)
    at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5001)
    at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
    at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
    at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4948)
    at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4575)
    at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4516)
    at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2310)
    at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2780)
    at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
    at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:773)
    at java.desktop/java.awt.EventQueue.run(EventQueue.java:722)
    at java.desktop/java.awt.EventQueue.run(EventQueue.java:716)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
    at java.desktop/java.awt.EventQueue.run(EventQueue.java:746)
    at java.desktop/java.awt.EventQueue.run(EventQueue.java:744)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
    at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:743)
    at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
    at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
    at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

class HintAL implements ActionListener{
    String Arrayword;
    boolean match;
    @Override
    public void actionPerformed(ActionEvent e) {
        match = true;
        Arrayword = null;
        for (int i = 0; i < wordlist.size(); i++) {
            Arrayword = wordlist.get(i);
            for (int j = 0; j < builtwordcheck.length(); j++) {
                if (Arrayword.charAt(j) != builtwordcheck.charAt(j) || Arrayword.length() <= builtwordcheck.length() /* add condition for having reached the end of the array word (.length) */){
                    match = false;
                }
            }
            if (match == true){
                System.out.println(Arrayword);
            }
            match = true;
        }
    }
}

Answer 1

您的代码的以下行抛出 StringIndexOutOfBoundsException。

if (Arrayword.charAt(j) != builtwordcheck.charAt(j) || Arrayword.length() <= builtwordcheck.length() /* add condition for having reached the end of the array word (.length) */){

这是因为 j 的值 而不是 小于 Arrayword 的长度。

现有代码的最简单修复方法是简单地交换 if 条件中的顺序，即

if (Arrayword.length() <= builtwordcheck.length() || Arrayword.charAt(j) != builtwordcheck.charAt(j)) {

更好的解决方案是调用方法 contains。

if (Arrayword.contains(builtwordcheck)) {

一个更好的解决方案——如果你至少使用 Java 8——是使用 streams.

class HintAL implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        wordlist.stream()
                .filter(s -> s.contains(builtwordcheck))
                .forEach(System.out::println);
    }
}

注意上面代码的最后一行使用了method references（也是在Java8中添加的）

另请注意，建议遵守Java naming conventions。

另外，我觉得推荐给你这本书比较合适Java by Comparison

在搜索超过 2 个匹配字母的单词时尝试比较数组列表中的匹配单词时出错

Error when trying to compare matching words from an arraylist when searching through words with more than 2 matching letters

java

arrays

string

arraylist

cycle