Java报bad operand types for binary operator "=="错误的解决方法

编写Java代码时，判断从字符串中取出的char字符是否等于"1"时，运行抛出bad operand types for binary operator错误，报错相关代码如下：

import java.util.Scanner;
public class Q3 {
    public static void main (String[] args){
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter any number: ");
        int num = scan.nextInt();
        int length = String.valueOf(num).length();
        int reverse = 0;
        if (length<=3) {
            while(num != 0) {  
                int remainder = num % 10;  
                reverse = reverse * 10 + remainder;  
                num = num/10;  
        }       
        String word = "";
        String numword=String.valueOf(reverse);
        char character = numword.charAt(0);
        System.out.println(character=="1");}}}

问题原因及修复方案 #

• 核心问题是字面量类型不匹配：Java中""双引号包裹的是String类型，''单引号包裹的才是char类型字面量，char类型无法直接和String类型用==运算符做相等判断
• 修复方式非常简单，只需把比较语句中的双引号替换为单引号即可，修改后的对应代码行：
  System.out.println(character == '1');

内容的提问来源于stack exchange，提问作者Ngawang Tobden