java - 我应该将抛出异常放在链式重载构造函数中的哪里？

Question

我是否需要在每个构造函数上放置 throws 子句，或者只是将最终重载的构造函数传递给父类(super class)？

  //Constructors
  public ManufacturedPart(){
    this(0, null, 0, 0, 0);
  }
  public ManufacturedPart(int id){
    this(id, null, 0, 0, 0);
  }
  public ManufacturedPart(int id, double lCost, double mCost){
    this(id, null, 0, lCost, mCost);
  }
  public ManufacturedPart(int id, String desc, double sellPrice, double lCost, double mCost){
    super(id, desc, sellPrice);
    setLaborCost(lcost);
    setMaterialCost(mCost);
  }

  //Set Labor Cost
  public void setLaborCost(double lCost) throws InvalidProductionArgumentException {
    if(lCost < 0)
      throw(new InvalidProductionArgumentException("Labor cost can't be less than 0"));
    else if(lCost >= 0)
      laborCost = lCost;
  }

  //Set Material Cost
  public void setMaterialCost(double mCost) throws InvalidProductionArgumentException {
    if(mCost < 0)
      throw(new InvalidProductionArgumentException("Material cost can't be less than 0"));
    else if(mCost >= 0)
      materialCost = mCost;
  }

Answer 1

Do I need to place the throws clause on each constructor or just the final overloaded constructor being passed to the super class?

您需要将其放置在可能出现此异常的每个构造函数上。例如

public ManufacturedPart(int id) { // thrown not possible
     this(id, null, 0, 0, 0);
}

public ManufacturedPart(int id, double lCost, double mCost) 
         throws InvalidProductionArgumentException  { // it could happen here
    this(id, null, 0, lCost, mCost);
}

如果异常是受检查的异常，您需要重构它，这样您就不必处理不可能发生的受检查的异常。

public ManufacturedPart(int id) { // thrown not possible
     super(id, null, 0); // use super instead of a constructor which throws an exception
}