方法定义中的 Java 异常

Question

这个问题已经有答案了:

Understanding checked vs unchecked exceptions in Java (21 个回答)

Checked vs Unchecked Exceptions in Java (8 个回答)

已关闭 5 年前。

什么时候必须在方法定义中编写可抛出异常？

例如，我的构造函数可以同时使用:

public Test(int s, String t) {
  if (s <= 0 || t == null) {
    throw new IllegalArgumentException();
  }
  this.s = s;
  this.t = t;
}

或者:

public Test(int s, String t) throws IllegalArgumentException {
  if (s <= 0 || t == null) {
    throw new IllegalArgumentException();
  }
  this.s = s;
  this.t = t;
}

这个方法在没有它的情况下也可以工作:

public int mult(int n) {
  if (n < 0) {
    throw new IllegalArgumentException();
  }
  return n * this.s;
}

Answer 1

IllegalArgumentException 继承自RuntimeException。 RuntimeException以及从它继承的所有类都是未经检查的异常，不必声明。请参阅RuntimeException的JavaDoc:

/**
 * {@code RuntimeException} and its subclasses are <em>unchecked
 * exceptions</em>.  Unchecked exceptions do <em>not</em> need to be
 * declared in a method or constructor's {@code throws} clause if they
 * can be thrown by the execution of the method or constructor and
 * propagate outside the method or constructor boundary.
 */