Java中的Validation.Exception如何工作？

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我对Java还是很陌生，并且正在努力理解Exception。 在一个练习中，我应该在类“ ValidatorImpl”和方法“ User＃validate”中实现接口“ exceptions.excercise.Validator”。 我正在努力了解这些代码行中到底发生了什么，如果有人可以帮助我，我将非常感激:)：

我不确定您是否需要整个java项目来理解代码，但这是我不太了解的内容： *在User.java中

public void validate() throws UserException {
    Validator valid = new ValidatorImpl();

    try {
        valid.validateAge(this.getAge());
        valid.validateEmailWithRuntimeException(this.getEmail());
    } catch (ValidationException e) {
        throw new UserException("age is incorrect", e);
    } catch(ValidationRuntimeException e ) {
        throw new UserException("mail is incorrect", e);
    }
}

在ValidatorImpl.java中： 打包exceptions.execercise;

公共类ValidatorImpl实现了Validator {

@Override
public void validateAge(int age) throws ValidationException {

    if ((age < 0) || (age > 120)) {
        throw new ValidationException(age + "not betweeon 0 and 120");
    }
}

@Override
public void validateEmailWithRuntimeException(String email) {

    if (email == null) {
        throw new ValidationRuntimeException("email is null");
    }
    if (!email.contains("@")) {
        throw new ValidationRuntimeException("email must contain @sign");
    }
}

}

我知道这很多。 谢谢，如果您阅读所有这些内容：)

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verror
verror

First, you have a try-catch block. This will catch exceptions thrown in the try-part and if an exception is found they'll run the catch-block for the type of exception. The methods valid.validateAge(int) and valid.validateEmailWithRuntimeException(String) both can throw exceptions. If the age is under 0 or over 120 validateAge will throw an ValidationException. The try-catch will catch that and will run the first catch-block, which will output a new UserExeption("age is incorrect"). If the age is valid, validateEmailWithRuntimeException will be called next. This works the same way! If the Email is invalid, a ValidationRuntimeException will be thrown and catched. In this case, the second catch-block will be called and a new UserExeption("mail is incorrect") will be outputted.

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