如何在Java中引发一般异常? [英] How can I throw a general exception in Java?

问题描述

考虑这个简单的程序.该程序有两个文件:

Consider this simple program. The program has two files:

class Vehicle {
    private int speed = 0;
    private int maxSpeed = 100;

    public int getSpeed()
    {
        return speed;
    }

    public int getMaxSpeed()
    {
        return maxSpeed;
    }

    public void speedUp(int increment)
    {
        if(speed + increment > maxSpeed){
            // Throw exception
        }else{
            speed += increment;
        }
    }

    public void speedDown(int decrement)
    {
        if(speed - decrement < 0){
            // Throw exception
        }else{
            speed -= decrement;
        }
    }
}

文件 HelloWorld.java

public class HelloWorld {

    /**
     * @param args
     */
    public static void main(String[] args) {

        Vehicle v1 = new Vehicle();
        Vehicle v2 = new Vehicle();

            // Do something

            // Print something useful, TODO
        System.out.println(v1.getSpeed());
    }

}

正如您在第一堂课中所看到的，我在我想抛出异常的地方添加了一条注释("//throw exception").我必须为异常定义自己的类，还是可以在Java中使用一些常规的异常类?

As you can see in the first class, I have added a comment ("// throw exception") where I would like to throw an exception. Do I have to define my own class for exceptions or is there some general exception class in Java I can use?

推荐答案

您可以创建自己的Exception类:

You could create your own Exception class:

public class InvalidSpeedException extends Exception {

  public InvalidSpeedException(String message){
     super(message);
  }

}

在您的代码中:

throw new InvalidSpeedException("TOO HIGH");

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