我有一個(gè)由不同類(lèi)型組成的數(shù)組列表。我想使用數(shù)組列表中的get方法從指定的索引中只提取一個(gè)元素public BookCollection() { collection = new ArrayList<Book>(10);}public void addbook(String title, String author, int year, double cost, boolean Available) { Book a = new Book(title, director, year, cost, Available); collection.add(a);}在上面的代碼中，我想創(chuàng)建一個(gè)圖書(shū)庫(kù)，但在某些時(shí)候我只想要標(biāo)題。public static void main(String[] args) { BookCollection library = new BookCollection(); library.addbook("Pride & Prejudice", "Jane Austen", 1801, 24.95, true); System.out.println(collection.get(0).toString())}然后我只想得到標(biāo)題。所以在這種情況下，它會(huì)是傲慢與偏見(jiàn)。目前輸出是“傲慢與偏見(jiàn)Jane Austen180124.95”但我希望它只是“傲慢與偏見(jiàn)”。
2 回答
慕慕森
TA貢獻(xiàn)1856條經(jīng)驗(yàn) 獲得超17個(gè)贊
技嘉的回答是對(duì)的。您應(yīng)該在 Book 類(lèi)中為每個(gè)字段創(chuàng)建 getter 方法，以便您可以隨時(shí)單獨(dú)調(diào)用。
您還應(yīng)該檢查 Java 規(guī)則和約定，在這種特殊情況下，變量和方法名稱(chēng)應(yīng)該以小寫(xiě)字母開(kāi)頭，因此您應(yīng)該從“Available”切換到“available”。
大寫(xiě)字母用于類(lèi)。
我嘗試了您的代碼并找到了解決方案，希望它適合您：
這是 BookCollection 類(lèi)：
public class BookCollection extends ArrayList<Book>{
private static final long serialVersionUID = 1L;
private ArrayList<Book> collection;
public BookCollection() {
this.collection = new ArrayList<Book>();
}
public void addbook(String title, String author, int year, double cost, boolean available) {
Book a = new Book(title, author, year, cost, available);
this.add(a);
}
public static void main(String[] args) {
BookCollection library = new BookCollection();
library.addbook("Pride & Prejudice", "Jane Austen", 1801, 24.95, true);
System.out.println(library.get(0).isAvailable());
}
}
這是 Book 類(lèi)，帶有 getter 和 setter：
public class Book {
private String name;
private String author;
private int year;
private double cost;
private boolean available;
public Book(String name, String author, int year, double cost, boolean available){
this.name = name;
this.author = author;
this.year = year;
this.cost = cost;
this.available = available;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public double getCost() {
return cost;
}
public void setCost(double cost) {
this.cost = cost;
}
public boolean isAvailable() {
return available;
}
public void setAvailable(boolean available) {
this.available = available;
}
}
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