如何在Java中忽略键输入的大小写

String input = "Hello";
String key = "hello";

if (input.equalsIgnoreCase(key)) {
    System.out.println("输入的键与关键字匹配（忽略大小写）");
} else {
    System.out.println("输入的键与关键字不匹配");
}

String input = "Hello";
String key = "hello";

if (input.toUpperCase().equals(key.toUpperCase())) {
    System.out.println("输入的键与关键字匹配（忽略大小写）");
} else {
    System.out.println("输入的键与关键字不匹配");
}

import java.util.regex.Pattern;
import java.util.regex.Matcher;

String input = "Hello";
String key = "hello";

Pattern pattern = Pattern.compile(key, Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(input);

if (matcher.find()) {
    System.out.println("输入的键与关键字匹配（忽略大小写）");
} else {
    System.out.println("输入的键与关键字不匹配");
}