如何在Java中比较忽略大小写的字符串

在这里，我是新手，我正在尝试比较品牌并将其显示为一组字符串。似乎现在可以正常工作，但是我不知道如何使比较不区分大小写。到目前为止，我找到的所有选项都是将一个字符串与另一个字符串进行比较。有什么办法可以进行比较？现在，仅接受字符串数组中所述的值。

PS：这是我们老师希望我们以此为基础的现有作业，因此为什么我要使用“ isValid”方法进行验证。

谢谢！

    import com.entertainment.Television;
    import java.util.Arrays;
    import java.util.Scanner;
    
    class TelevisionConsoleClient {
    
        private static final Scanner scanner = new Scanner(System.in);
    
        public static void main(String[] args) {
            welcomeMessage();
        }
    
        public static void welcomeMessage() {
    
            //Welcome message to buyer
            System.out.println("Welcome to Our Online Ordering System.");
            System.out.println("Please answer the questions below to submit your order.");
    
            String brand = brandChoice();
            String display = displayChoice();
            int size = sizeChoice();
    
            System.out.println("Thank you. The television you ordered is: ");
            television(brand, display, size);
    
            //close scanner
            scanner.close();
        }
    
    
        public static String brandChoice() {
            String brandChoice = null;
            boolean hasBrand = false;
    
            while (!hasBrand) {
    
                System.out.println("Please enter the desired brand " + Arrays.toString(Television.VALID_BRANDS) + ":");
                brandChoice = scanner.nextLine();
    
                if (Television.isValidBrand(brandChoice))
                    hasBrand = true;
                else
                    System.out.println("Sorry " + brandChoice + " is not a valid brand");
            }
            return brandChoice;
        }
    
        private static String displayChoice() {
            String displayChoice = null;
            boolean hasDisplay = false;
    
            while (!hasDisplay) {
    
                System.out.println("Please enter the desired display type " + Arrays.toString(Television.VALID_DISPLAY) + ":");
                displayChoice = scanner.nextLine();
    
                if (Television.isValidDisplay(displayChoice))
                    hasDisplay = true;
                else
                    System.out.println("Sorry " + displayChoice + " is not a valid display type");
            }
            return displayChoice;
        }
    
        private static int sizeChoice() {
            Integer sizeChoice = null;
            boolean hasSize = false;
    
            while (!hasSize) {
    
                System.out.println("Please enter the desired size " + Arrays.toString(Television.VALID_SIZES) + ":");
                sizeChoice = Integer.parseInt(scanner.nextLine());
    
                if (Television.isValidSize(sizeChoice))
                    hasSize = true;
                else
                    System.out.println("Sorry " + sizeChoice + " is not a valid size");
            }
            return sizeChoice;
        }
    
        private static void television(String brand, String display, int size) {
            System.out.println(new Television(brand, display, size));
        }
    
    }


package com.entertainment;

public class Television {

    // CLASS OR STATIC VARIABLES - STORED IN THE SHARED AREA ASSOCIATED WITH A CLASS
    public static final String[] VALID_BRANDS = {"Samsung", "LG", "Sony", "Toshiba"};
    public static final String[] VALID_DISPLAY = {"LED", "OLED", "PLASMA", "LCD", "CRT"};
    public static final int[] VALID_SIZES = {32, 40, 43, 50, 55, 60, 65, 70, 75, 80};

    // FIELDS - AKA 'INSTANCE VARIABLES', 'ATTRIBUTES', 'PROPERTIES'
    private String brand;
    private String display;
    private int size;


    // CONSTRUCTORS
    // No-arg constructor.
    public Television() {
        // possible additional "setup" or initialization code here
        // want it to run for every instance created
    }

    // 3-arg constructor
    public Television(String brand, String display, int size) {
        this.brand = brand;
        this.display = display;
        this.size = size;
    }


    // ACCESSOR METHODS (getters/setters)

    public String getBrand() {
        return brand;
    }

    public String getDisplay() {
        return display;
    }

    public int getSize() { return size; }


    public static boolean isValidBrand(String brand) {
        boolean isValid = false;

        for (String currentBrand : VALID_BRANDS) {
            if (currentBrand.equals(brand)) {
                isValid = true;
                break;
            }
        }
        return isValid;
    }

    public static boolean isValidDisplay(String display) {
        boolean isValid = false;

        for (String currentDisplay : VALID_DISPLAY) {
            if (currentDisplay.equals(display)) {
                isValid = true;
                break;
            }
        }
        return isValid;
    }

    public static boolean isValidSize(int size) {
        boolean isValid = false;

        for (int currentSize : VALID_SIZES) {
            if (currentSize == size) {
                isValid = true;
                break;
            }
        }
        return isValid;
    }

    public String toString() {
        return "Television: " + getBrand() + ", Display: " + getDisplay() + ", Size: " + getSize() + " inches.";
    }
}