Java界面不声明任何异常。如何管理检查异常的实现？

问题描述

假设我有以下Java界面，我可能不会修改：

  public interface MyInterface {
 public void doSomething（）; 
} 
  

现在执行它的类是这样的：

  class MyImplementation实现MyInterface {
 public void doSomething（）{
 try {
 //读取文件
} catch（IOException e）{
 //该怎么办？ 
} 
} 
} 
  

我无法从没有阅读文件。

RuntimeException 的子类可以清楚地帮助我，但我不知道是否正确的事情：问题是那个异常然后不会被记录在类中，并且类的用户可能会得到这个异常对于解决这个问题一无所知。

---

我们都同意：界面有问题。

解决方案我选择

我终于决定写一个 MyVeryOwnInterface 扩展 MyInterface 并作为错误方法的签名的一部分添加 MyRuntimeException ：

  public interface MyVeryOwnInterface extends MyInterface {
 public void doSomething（）throws MyRuntimeException; 
} 
 class MyImplementation实现MyVeryOwnInterface {
 public void doSomething（）throws MyRuntimeException {
 try {
 //读取文件
} catch（IOException e） {
抛出新的MyRuntimeException（无法读取文件，e）; 
} 
} 
} 
  

解决方案

您已经遇到的问题。没有一个很好的解决方案，并且使用 RuntimeException 几乎是唯一可以做的。

可以说，这也是为什么检查异常是一个失败的概念的例子。

Let's say I have the following Java interface that I may not modify:

public interface MyInterface {
  public void doSomething();
}

And now the class implementing it is like this:

class MyImplementation implements MyInterface {
  public void doSomething() {
    try {
      // read file
    } catch (IOException e) {
      // what to do?
    }
  }
}

I can't recover from not reading the file.

A subclass of RuntimeException can clearly help me, but I'm not sure if it's the right thing to do: the problem is that that exception would then not be documented in the class and a user of the class would possibly get that exception an know nothing about solving this.

What can I do?

---

We all agree: the interface is faulty.

Solution I chose

I finally decided to write a MyVeryOwnInterface that extends MyInterface and adds as part of the signature of the faulty methods the MyRuntimeException:

public interface MyVeryOwnInterface extends MyInterface {
  public void doSomething() throws MyRuntimeException;
}
class MyImplementation implements MyVeryOwnInterface {
  public void doSomething() throws MyRuntimeException {
    try {
      // read file
    } catch (IOException e) {
      throw new MyRuntimeException("Could not read the file", e);
    }
  }
}

解决方案

You've encountered the problem of leaky abstractions. There is no really good solution, and using a RuntimeException pretty much the only thing you can do.

Arguably, this is also an example for why checked exceptions are a failed concept.

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