在另一个类中创建一个方法来打印ArrayList中，然后调用它

本文介绍了在另一个类中创建一个方法来打印ArrayList中，然后调用它的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我已经建立了我的班书目一个ArrayList，但我需要它在另一个类打印。

我想我可能把一个ArrayList的印刷进入一个方法，所以那么它可以从不同的类调用;如果我错了，虽然，还有什么可以做我做到这一点？

下面是我的code，以供参考。

进口的java.util.ArrayList;公共类书目{公共静态无效的主要（字串[] args）{    书=新的图书（）;    a.setTitle（随机）;    a.setAuthor（克雷格·罗伯逊）;    a.setBookID（1847398812）;    a.setonLoan（假）;    a.setNumberofLoans（3）;    图书B =新的图书（）;    b.setTitle（最后的避难所）;    b.setAuthor（克雷格·罗伯逊）;    b.setBookID（1471127753）;    b.setonLoan（假）;    b.setNumberofLoans（2）;    图书C =新的图书（）;    c.setTitle（未唱鸟）;    c.setAuthor（亚历克斯灰色）;    c.setBookID（0751548278）;    c.setonLoan（真）;    c.setNumberofLoans（7）;    ArrayList的＆LT;图书＆GT;书目=新的ArrayList＆LT;图书＆GT;（）;    BookList.add（一）;    BookList.add（二）;    BookList.add（C）;    诠释计数= BookList.size（）;    的System.out.println（伯爵：+计数）;    的System.out.println（）;        对于（图书D：书目）{            的System.out.println（D）;    }  }}

要顺应这一点，我在我的图书类中的toString（）方法，这样我就可以打印所有对象。

另外一个问题：我如何将打印每个对象的只是标题和作者

解决方案

创建的静态在图书类的方法将处理的显示

公共静态无效showBook​​s（ArrayList的＆LT;图书＆GT;书）{    对于（图书D：书籍）{        的System.out.println（D）; //调用每个Book对象的'的toString'方法}

和调用它这种方式从主要方法：

的ArrayList＆LT;图书＆GT;书目=新的ArrayList＆LT;图书＆GT;（）;BookList.add（一）;BookList.add（二）;BookList.add（C）;Book.showBook​​s（书目）; //打印的书籍，一个一个

  

我将如何打印每个对象的只是标题和作者？

您可以选择打印标题和作者仅在重写 的toString 你的图书类的方法：

@覆盖公共字符串的toString（）{    //'作家'和; '称号'是'书'类的成员    回归作者：+ +作家 - 标题：+称号;}

I've built an Arraylist in My class 'BookList', but I need it to print in another class.

I think I may have to turn the printing of an Arraylist into a method, so then it can be called from a different class; if I am wrong though, what else could I do to accomplish this?

Below is my code, for reference.

import java.util.ArrayList; public class BookList { public static void main (String[] args){ Book a = new Book(); a.setTitle("Random "); a.setAuthor("Craig Robertson"); a.setBookID("1847398812"); a.setonLoan(false); a.setNumberofLoans(3); Book b = new Book(); b.setTitle("The Last Refuge"); b.setAuthor("Craig Robertson"); b.setBookID("1471127753"); b.setonLoan(false); b.setNumberofLoans(2); Book c = new Book(); c.setTitle("The Bird That Did Not Sing"); c.setAuthor("Alex Gray"); c.setBookID("0751548278"); c.setonLoan(true); c.setNumberofLoans(7); ArrayList<Book> BookList = new ArrayList<Book>(); BookList.add(a); BookList.add(b); BookList.add(c); int count = BookList.size(); System.out.println("Count: " + count); System.out.println(""); for (Book d : BookList){ System.out.println(d); } } }

To go with this, I have the toString() method in my 'Book' class, so I could print all objects.

An additional question: How would I print just the title and author of each object?

解决方案

Create a static method in your Book class that will handle the display:

public static void showBooks(ArrayList<Book> books) { for (Book d : Books){ System.out.println(d); // calls the 'toString' method on each Book object }

And call it this way from the main method:

ArrayList<Book> BookList = new ArrayList<Book>(); BookList.add(a); BookList.add(b); BookList.add(c); Book.showBooks(BookList); // prints the books, one by one

How would I print just the title and author of each object?

You can choose to print the title and author only in the overriden toString method of your Book class:

@Override public String toString() { // 'author' & 'title' are members of the 'Book' class return "Author: " + author + "- Title: " + title; }