在Java錯誤中引發多個異常

Question

錯誤：未報告的異常NotEnoughBalance; 必須被抓住或宣布被拋出

錯誤：未報告的異常NegativeWithdraw; 必須被抓住或宣布被拋出

基本上，我不確定在拋出異常並在滿足條件時創建新異常時如何不報告異常。 我的問題主要涉及以下事實：我將兩個catch異常放入同一方法中，僅使用一個異常不會產生任何錯誤。

這些是在我的對象類中共享方法的try演示語句

try {
    account.withdraw(passNegative);
}
catch(NegativeWithdraw e) {
    System.out.println(e.getMessage());
}

代碼的不同部分

try {
    account.withdraw(1);
}
catch(NotEnoughBalance e) {
    System.out.println(e.getMessage());
}

當程序捕獲到這兩個異常時，我在這里定義輸出：

public class NegativeWithdraw extends Exception {
    // This constructor uses a generic error message.
    public NegativeWithdraw() {
        super("Error: Negative withdraw");
    }
   // This constructor specifies the bad starting balance in the error message.
   public NegativeWithdraw(double amount) {
        super("Error: Negative withdraw: " + amount);
    }
}

不同的程序

public class NotEnoughBalance extends Exception {
    // This constructor uses a generic error message.
    public NotEnoughBalance() {
        super("Error: You don't have enough money in your bank account to withdraw that much");
    }

    // This constructor specifies the bad starting balance in the error message.
    public NotEnoughBalance(double amount) {
        super("Error: You don't have enough money in your bank account to withdraw $" + amount + ".");
    }
}

這是我的對象類，可以很好地進行編譯，但是我認為這是我的程序所在的位置。 我在網上尋找如何在一個方法中包含多個異常，並發現在拋出異常之間使用了一個共同點，但是對於我做錯的事情仍然有些困惑。

public class BankAccount {
    private double balance; // Account balance

    // This constructor sets the starting balance at 0.0.
    public BankAccount() {
        balance = 0.0;
    }

    // The withdraw method withdraws an amount from the account.
    public void withdraw(double amount) throws NegativeWithdraw, NotEnoughBalance {
        if (amount < 0)
            throw new NegativeWithdraw(amount);
        else if (amount > balance)
            throw new NotEnoughBalance(amount);
        balance -= amount;
    }

    //set and get methods (not that important to code, but may be required to run)
    public void setBalance(String str) {
        balance = Double.parseDouble(str);
    }

    // The getBalance method returns the account balance.
    public double getBalance() {
        return balance;
    }
}

Answer 1

每次調用account.withdraw函數時，都需要捕獲這兩個異常，因為您不知道將拋出哪個異常（您可能知道，但是編譯器不知道）

例如

try {
     account.withdraw(passNegative);
}
catch(NegativeWithdraw | NotEnoughBalance e) {
    System.out.println(e.getMessage());
}

編輯：如另一個用戶所述，這是針對Java 7的

對於較舊的版本，您可以做很多事情

try {
    account.withdraw(passNegative);
} catch(NegativeWithdraw e) {
    System.out.println(e.getMessage());
} catch(NotEnoughBalance e) {
    System.out.println(e.getMessage());
}