加入法Java類

Question

比方說，我有一個Money類，看起來像這樣：

public class Money { 
    private BigDecimal amount; 
    private Currency currency; 
} 

我想補充兩個這樣的類在一起，例如

Money m1 = Money(5); 
Money m2 = Money(10); 
Money m3 = m1+m2; // m3.amount should be 15 

我該如何編寫一個方法，以便我可以將這兩個Money類加在一起？

Answer 1

Java不支持操作符重載，而不是你需要添加一個附加功能：

public class Money { 
    private BigDecimal amount; 
    private Currency currency; 

    public Money add(Money m) { 
     Money res = new Money(); 
     if (!currency.equals(m.currency)) { 
      throw new UnsupportedOperationException(); 
     } 
     res.currency = currency; 
     res.amount = m.amount.add(amount); 
     return res; 
    } 
} 

Money result = one.add(two);