如何在重载的构造函数中调用 mutator 方法而不是在 java 中分配它们？

Question

 public class Player
{
private String firstName;
private String lastName;
private int heightInInches;
private double weightInPounds;
private boolean goalScorer;
private boolean drinksBeer;

public Player(){
}

public Player(String firstName, String lastName, int heightInInches, double weightInPounds, boolean goalScorer, boolean drinksBeer){
    if(lastName != null && lastName.trim().length() > 0){
        if(lastName != null && lastName.trim().length() > 0){
            if(heightInInches >= 0){ 
                if(weightInPounds >= 0){
                    this.firstName = firstName;
                    this.lastName = lastName;
                    this.heightInInches = heightInInches;
                    this.weightInPounds = weightInPounds;
                    this.goalScorer = goalScorer;
                    this.drinksBeer = drinksBeer;

                }
            }
        }
    }
}

public String getFirstName(){
    return firstName;
}

public String getLastName(){
    return lastName;
}

public int getHeightInInches(){
    return heightInInches;
}

public double getWeightInPounds(){
    return weightInPounds;
}

public boolean getGoalScorer(){
    return goalScorer;
}

public boolean getDrinksBeer(){
    return drinksBeer;
}

public void setFirstName(String firstName){
    if(firstName != null && firstName.trim().length() > 0){
        this.firstName = firstName;
    }else{
        System.out.println("Error. Invalid First Name.");
    }

}

public void setLastName(String lastName){
    if(lastName != null && lastName.trim().length() > 0){
        this.lastName = lastName;
    }else{
        System.out.println("Error. Invalid Last Name.");
    }

}

public void setHeightInInches(int heightInInches){
    if(heightInInches >= 0){
        this.heightInInches = heightInInches;
    }else{
        System.out.println("Error. Invalid Height.");
    }

}

public void setWeightInPounds(double weightInPounds){
    if(weightInPounds >= 0){
        this.weightInPounds = weightInPounds;
    }else{
        System.out.println("Error. Invalid Weight.");
    }

}

public void setGoalScorer(boolean goalScorer){
    this.goalScorer = goalScorer;
}

public void setDrinksBeer(boolean drinksBeer){
    this.drinksBeer = drinksBeer;
}


}

在重载的构造函数中，如何为每个字段调用 mutator 方法而不是使用赋值语句？另外，如果我调用增变器方法，我是否应该删除构造函数中的 if 语句？（我正在使用 blueJ）我是初学者，所以请提及我的代码中是否还有其他问题。提前致谢。

Answer 1

您所要做的就是像任何其他方法一样引用增变器方法：

public Player(String firstName, String lastName, int heightInInches, double weightInPounds, boolean goalScorer, boolean drinksBeer) {
    setFirstName(firstName);
    setLastName(lastName);
    setHeightInInches(heightInInches);
    setWeightInPounds(weightInPounds);
    setGoalScorer(goalScorer);
    setDrinksBeer(drinksBeer);
}

此外，不需要那些 if 语句，因为它们实际上并没有做任何有用的事情。如果您没有显式设置任何值，int 变量将默认为 0，double 将默认为 0.0，boolean 将默认为 false，String 将默认为 null。所以你的 if 语句正在做 "If the first name is null, don't set it . . . so it'll just be null anyway by default."

如果你想做一些事情，比如强制高度为正数，你总是可以把那个逻辑放在 setter.

如何在重载的构造函数中调用 mutator 方法而不是在 java 中分配它们？

How to call the mutator methods in an overloaded constructor instead of assigning them in java?

java

mutators

bluej