在arraylist中搜索實例變量

Question

我正在嘗試創建一種方法，該方法將從另一個類返回一個對象。

例如：

public Book searchTitle(String title) {
    for (Book book : library) {
        if (book.getTitle().equals(title)) {
            return book;
        }
    }

// If the book is not found, I have no return and the program won't compile.
//How do I make the method work in the case that the book is not found? 

Answer 1

如果找不到Book則返回null或引發異常：

public Book searchTitle(String title) {
    for (Book book : library) {
        if (book.getTitle().equals(title)) {
            return book;
        }
    }
    return null;
}