我在写作业的时候，出现了问题但是我不知道为什么会这样？这是一个借书系统

Question

//package jie_shu_xi_tong;

import java.util.*;

class LibrarySystem{

public static void main(String args[]){

System.out.println("001号借书系统为您服务请选择您要的服务："+"\n"+

                  "(1)    按照书名查找"+"\n"+

                  "(2)    按照图书序号查找");

}

}

public class BookData{

/*这是问题     E:\java 笔记和错误\yuanwenjian\LibrarySystem.java:15: class BookData is public, should be declared in a file named BookData.java*/

public class BookData{

String Bookdata[] = new String[2];//Bookdata代表图书资料，存储书本的名称

public BookData(){

Bookdata[0] = "孙子兵法";

Bookdata[1] = "黄帝内经";

}

}

public class BookFind extends BookData{

/*这是问题      

E:\java 笔记和错误\yuanwenjian\LibrarySystem.java:23: class BookFind is public, should be declared in a file named BookFind.java

public class BookFind extends BookData{

*/

public BookFind(String BF){

BookData B = new BookData();

for(int i=0;i<B.Bookdata.length;i++){

if(B.Bookdata[i].equale(BF)){

/*这是问题

E:\java 笔记和错误\yuanwenjian\LibrarySystem.java:28: cannot find symbol

symbol  : method equale(java.lang.String)

location: class java.lang.String

                        if(B.Bookdata[i].equale(BF)){

*/

System.out.println("您要的书");

}

}

}

}

Answer 1

java的类需要在单独文件中，入门必知哦