effective_builder

我自己写的

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 carbohydrate ;

    private NutritionFacts(Builder builder) {
        servingSize = builder.servingSize;
        servings = builder.servings;
        calories = builder.calories;
        fat = builder.fat;
        sodium = builder.sodium;
        carbohydrate = builder.carbohydrate;        
    }
    

    public static class Builder {
        
        private final int servingSize;
        private final int servings;

        int calories = 0;
        int fat = 0;
        int sodium = 0;
        int carbohydrate = 0;

        public Builder(int servingSize, int servings){
            this.servings = servings;
            this.servingSize = servingSize;
        }

        public Builder calories(int val){
            this.calories = val;
            return this;
        }

        public Builder fat(int val){
            this.fat = val;
            return this;
        }

        public Builder sodium(int val){
            this.sodium = val;
            return this;
        }

        public Builder carbohydrate(int val){
            this.carbohydrate = val;
            return this;
        }

        public NutritionFacts build() {
            return new NutritionFacts(this);
        }


    }

    public static void main(String[] args) {
        NutritionFacts nutritionFacts = new NutritionFacts.Builder(240, 8).calories(100).sodium(45).calories(57).build();
    }



}

其他博客参考

http://blog.youkuaiyun.com/lms1719/article/details/70741691