java - 使用从扫描仪获取的字符串不起作用？

Question

当我运行程序并输入等级和性别时，它会对我大喊大叫，告诉我这是一个无效的性别。我不明白为什么如果我在控制台中输入“male”，它不等于字符串“male”？请向我解释为什么这不起作用，也许还有一些关于如何修复它的建议？谢谢!

import java.io.File;
import java.io.IOException;
import java.util.Scanner;

public class BabyNames {

public static void main(String[] args) throws IOException {
    Scanner input = new Scanner(System.in);
    System.out.print("Enter male or female: ");
    String gender1 = input.next();
    System.out.print("Enter rank: ");
    int rank = input.nextInt();         
    while (!(gender1 == "female" || gender1 == "male")){
            System.out.println("Please try again with a valid gender.");
            System.out.println("");
            System.out.println("Enter male or female: ");
            gender1 = input.next();
        }
    while (rank <= 0 || rank > 1000){
        System.out.println("Please try again with a valid rank.");
        System.out.println("");
        System.out.println("Enter rank: ");
        rank = input.nextInt();
    }

    findRank(gender1, rank);
}

public static void findRank(String gender2, int rank) throws IOException {
    File babyNames = new File("/home/skatty14/Downloads/BabyNames.txt");
    Scanner input = new Scanner(babyNames);
    int rankCount = 0;
    while (input.hasNextLine()){
        rankCount++;
        System.out.println(rankCount);
        if (gender2 == "male"){
            String name = input.next();
            System.out.println(name);
        }
        if (gender2 == "female"){
            String name = input.next();
            System.out.println(name);
        }
      }
   }
}

Answer 1

要比较字符串，您需要使用.equals()因此，将所有与 == 的字符串比较更改为使用 .equals() 。

if(gender1 == "male") { ... }

会变成，

if(gender1.equals("male")) { ... }

依此类推。