Java 小白 创建店员类，设计一个查询的成员方法，顾客咨询哪一类图书，店员就返回该类图书的名称，例如顾客咨询“计算机“,店员回复“《Java从入门到精通（第四版）》》“

package com.company;

import org.omg.PortableInterceptor.SYSTEM_EXCEPTION;

import java.util.Scanner;

public class Org
{

    public  static void main(String[] args)
    {
        System.out.println("想咨询哪一类图书");
        Scanner sc = new Scanner(System.in);
        String word = sc.nextLine();
        Org org = new Org();
        String shelf = "计算机";
        String  yuan = "历史";
        String mai = "英语";
        if (word.equals(shelf))
        {
            System.out.println("C");
        } else if (word.equals(yuan))
        {
            System.out.println("资治通鉴");
        }else if (word.equals(mai))
        {
            System.out.println("火星");
        }else {
            System.out.println("无效书类");        }
    }

}

另外一种：if return 调用成员方法的参数

import java.util.Scanner;

public class BorrowABook
{
    public static void main(String[] args)
    {
        BorrowABook book = new BorrowABook();
        String a = "《Java从入门到精通》";
        String b = "资治通鉴";
        String c = "火星英语";
        String e = "计算机";
        String f = "英语";
        String g = "历史";
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入书籍类型");
        String word = sc.nextLine();
        System.out.println("答复" + book.add(a, b, c,e,f,g,word));
    }

    String add(String a, String b, String c,  String e, String f, String g,String word)
    {
        if (word.equals(e))
        {
            return a;
        } else if (word.equals(f))
        {
            return c;
        } else if (word.equals(g))
        {
            return b;
        } else
        {
            return "无效书籍";
        }
    }
}