java - Java错误中抛出多个异常

Question

错误:未报告异常NotEnoughBalance；必须被捕获或宣布被抛出

错误:未报告异常NegativeWithdraw；必须被捕获或宣布被抛出

基本上，我不确定当我抛出异常并在满足条件时创建新异常时，如何不报告异常。我的问题主要涉及这样一个事实:我在同一个方法中放置了两个 catch 异常，仅使用一个异常不会产生任何错误。

这些是在我的对象类中共享方法的 try 演示语句

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

代码的不同部分

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

这里是我定义程序捕获两个异常时的输出的位置:

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 + ".");
    }
}

这是我的对象类，它编译得很好，但我认为这是我的程序所在的位置。我在网上查找如何在一种方法中保存多个异常，发现您在抛出异常之间使用了通用的，但我仍然对我做错了什么感到有点困惑。

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

每次调用 account.withdraw 函数时，都需要捕获这两个异常，因为你不知道会抛出哪一个异常(你可能知道，但编译器不知道)

例如

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

编辑:正如另一位用户所指出的，这是针对 Java 7 的

对于旧版本，你可以做很长的路

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