Java 如何将元素添加到数组中？

Question

我的构造函数包含我的数组:

public Library(int maxNumberofTextBook)
{
    // initialise instance variables
    nextBook = 0;
    numberOfBorrowers = 0;
    numberOfChapters = 6;
    bookShelf = new Textbook[maxNumberofTextBook + 1];
    for (int i = 0; i < maxNumberofTextBook; i++)
        bookShelf[i] = new Textbook("Text book number" +i, numberOfChapters);
}

在此方法中，我希望数组接受参数输入并将其添加到上面的数组中:

public void returnBook(Textbook book)
{
    //add book into array//
    numberOfBorrowers -- ; 
    bookInShelf ++ ; 
}

Answer 1

从您的示例中，我看到您正在使用一个原始固定大小 数组，

  Textbook bookShelf []  =  new Textbook [maxNumberofTextBook];

要添加一个新对象，您只需分配它(可能会抛出ArrayOutOfBoundException)

public void returnBook(Textbook book)
    {
     if(bookInShelf  < maxNumberofTextBook ){ //just to avoid the exception
         bookShelf[maxNumberofTextBook - 1] = book;
         numberOfBorrowers -- ; 
         bookInShelf ++ ; 
     }

    }