java - 嵌套 If 语句 - 未收到预期输出 Java

Question

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How do I compare strings in Java? (23 个回答)

已关闭 7 年前。

这是一个简单的程序，询问用户两个问题。根据用户的输入，我们将显示对该对象的猜测。类似于游戏“20个问题”。无论我给程序输入什么，它总是将 myGuess 的值返回为“回形针”

我尝试注释掉每个 if/else 语句的内部并将输出设置为 1,2,3，但它仍然达到 3(回形针 block )。这让我认为我的字符串比较在用户输入或条件逻辑的分配中存在错误......这是代码:

import java.util.Scanner;

public class JavaTraining {


  public static void main(String[] args) {

      Scanner keyboard = new Scanner(System.in);
      String input1,input2;
      String myGuess;

      System.out.println("TWO QUESTIONS!");

      System.out.println("Think of an object, and I'll try to guess it.\r\n");

      System.out.println("Question 1) Is it an animal, vegetable, or mineral?");
      input1 = keyboard.nextLine();

      System.out.println("\r\nQuestion 2) Is it bigger than a breadbox?");
      input2 = keyboard.nextLine();

      if (input1 == "animal"){

          if (input2 == "yes"){
              myGuess = "moose";
          }
          else{
              myGuess = "squirrel";
          }
      }
      else if (input1 == "vegetable"){
          if (input2 == "yes"){
              myGuess = "watermelon";
          }
          else{
              myGuess = "carrot";
          } 
      }
      else{
          if (input2 == "yes"){
              myGuess = "Camaro";
          }
          else{
              myGuess = "paper clip";
          } 
      }

      System.out.println("\r\nMy guess is that you are think of a "+myGuess+".\r\nI would"
              +" ask you if I'm right, but I don't actually care."+input1+input2);
      }
  }

Answer 1

对字符串使用 .equals() 而不是 == 。 Java 字符串是对象而不是原始数据类型。

改变这个

     if (input1 == "animal")

至

    if(input1.equals("animal"))

看看这个 link