Java学习笔记（二）の遇到多个构造器参数时要考虑用构建器(二)

public class NutritionFacts {
private final int servingSize; // (mL) required
private final int servings; // (per container) required
private final int calories; // optional
private final int fat; // (g) optional
private final int sodium; // (mg) optional
private final int carbohydrate; // (g) optional

public NutritionFacts(int servingSize, int servings) {
this(servingSize, servings, 0);
}

public NutritionFacts(int servingSize, int servings,
int calories) {
this(servingSize, servings, calories, 0);
}

public NutritionFacts(int servingSize, int servings,
int calories, int fat) {
this(servingSize, servings, calories, fat, 0);
}

public NutritionFacts(int servingSize, int servings,
int calories, int fat, int sodium) {
this(servingSize, servings, calories, fat, sodium, 0);
}

public NutritionFacts(int servingSize, int servings,
int calories, int fat, int sodium, int carbohydrate) {
this.servingSize = servingSize;
this.servings = servings;
this.calories = calories;
this.fat = fat;
this.sodium = sodium;
this.carbohydrate = carbohydrate;
}

public static void main(String[] args) {
NutritionFacts cocaCola =
new NutritionFacts(240, 8, 100, 0, 35, 27);
}
}3.Builder模式，既能保证安全性，又能保证可读性。

[java] // Builder Pattern

public class NutritionFacts {
private final int servingSize;
private final int servings;
private final int calories;
private final int fat;
private final int sodium;
private final int car