如何比较 Java 中忽略大小写的字符串

Question

这里是新手，我正在尝试将品牌和展示与字符串数组进行比较。似乎现在正在工作，但我不知道如何使比较不区分大小写。到目前为止我发现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吗？现在只接受字符串数组中所述的值。

P.S。这是我们的讲师希望我们在其基础上构建的现有作业，因此我使用“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.";
    }
}

Answer 1

改变String.equals(Object) to String.equalsIgnoreCase(String)。也就是说，

if (currentBrand.equals(brand))
if (currentDisplay.equals(display))

至

if (currentBrand.equalsIgnoreCase(brand))
if (currentDisplay.equalsIgnoreCase(display))

如何比较 Java 中忽略大小写的字符串

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