这里是初学者-java IF ELSE与文本一起使用[重复]

Question

 if (LEAVE == "yes") {
        System.out.println("ok, lets go");
     if (LEAVE == "no") {
        System.out.println("you dont have a choice");
} else {
        System.out.println("it's a yes or no question");

package com.company;
import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        Scanner LEAVE = new Scanner(System.in);

        System.out.println("do you want to answer this test?");
        LEAVE.next();

        System.out.println("first q: would you leave the hotel?");
        LEAVE.next();
        if (LEAVE == "yes") {
            System.out.println("ok, lets go");
        }
        LEAVE.nextLine();
        if (LEAVE == "no") {
            System.out.println("you dont have a choice");
            LEAVE.nextLine();
        } else {
            System.out.println("it's a yes or no question");

        }
    }}

Answer 1

Scanner LEAVE = new Scanner(System.in);

暗示LEAVE是扫描器类对象。对啊。

if (LEAVE == "yes")

您正在比较扫描器类型对象和字符串类型对象，因此得到

Operator "==" cannot be applied to "java.util.scanner", "java.lang.String"

现在考虑一下

LEAVE.next();

String response = LEAVE.next()
if(response.equalsIgnoreCase("yes")){
   // do something
}else if(response.equalsIgnoreCase("no")){
   // do something else
}