java - 确保输入不为空

Question

这个问题已经有答案了:

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

已关闭 3 年前。

所以下面我有一个问题，我无法理解为什么它不起作用。java 代码的第一 block 完全按照我想要的方式工作(例如，将工资金额设置为任意值，如果不在范围内，则会出现错误并重复最初的问题。)

我的问题是在第二个代码块中，我假设再次创建 boolean 值并模拟上面的代码来检查我的输入是否为==“”，如果没有像以前一样冲洗并重复，但事实并非如此？我写得一模一样(当然改变了值)，但我根本无法让 t 发挥作用。如果有人可以帮助或指出我正确的道路，我会很感激:)

//第一 block ......

boolean salaryState = false;
         while (salaryState == false){
             System.out.print("Salary: ");
         salary = (input.nextDouble());     
            if(salary >= 45000 && salary <= 49999) {    //if salary amount in this range
                this.coachCategory = "Junior";          //then set coaches category to this
                salaryState = true;
         }
            else if(salary >= 50000 && salary <= 59999) {   //if salary amount in this range
                this.coachCategory = "Youth";               //then set coaches category to this
                salaryState = true;
         }
            else if(salary >= 60000 && salary <= 70000) {   //if salary amount in this range
                this.coachCategory = "Senior";              //then set coaches category to this
                salaryState = true; 
         }
            else {  //if invalid salary amount then print error

                if (salary <= 45000 && salary >= 70000);
                    System.out.println("ERROR: Salary range needs to be within 45 000 - 70 000.");

//第二 block ...

         boolean isName = false;
     while (isName == false) {
         System.out.print("Name: ");
     name = (input.nextLine());
        if(name != "") {
            this.name = name;
            isName = true;
        }
        else {
            if(name == "");
                System.out.println("ERROR: Please enter a name.");
        }

Answer 1

替换

名称 != ""与 "name.length()>0"

您的解决方案将会起作用。

这是完整的解决方案:

import java.util.Scanner;
public class Main
{
	public static void main(String[] args) {
	    String heroname;
	    Scanner input = new Scanner(System.in);
		System.out.println("Hello World");
		String name;
		boolean isName = false;
		while(isName==false){
		    System.out.println("Name: ");
		    name = (input.nextLine());
		    if(name.length()>0){
		        heroname = name;
		        isName = true;
		    }else{
	            System.out.println("Try Again");

		    }
		}
	}
	
}