Builder模式

Builder模式有什么好处？

构造函数构造一个函数的好处就是直接，但是缺点就是如果参数比较多，需要重载构造函数或者一个构造函数里面定义多个构造参数，对于调用方来讲十分不友好；

另外一种方式就是java bean模式，定义一个简洁的构造函数，然后通过set属性的方式来构造；这种方式避免了构造函数模式的那种参数众多的丑陋，但是同时却也带来潜在并发问题，就是可能该对象还没有构造完成就被别的线程拿去用了。

这种模式的优势合并在一起，同时摒弃劣势就是Builder模式；既可以定义一个简洁的构造函数，同时还可以一次性的将对象构建完毕。

Server端代码：

public class Dog {
    private final String name; // 名称
    private final String sex; // 性别
    private final int age; // 年龄
    private final String fur; // 毛发
    private final String breed; // 品种
    private final float weight; // 体重
    private final float height; // 身高

    private Dog(Builder builder) { // 私有构造方法，入参为内部类对象
        name = builder.name;
        sex = builder.sex;
        age = builder.age;
        fur = builder.fur;
        breed = builder.breed;
        weight = builder.weight;
        height = builder.height;
    }

    @Override
    public String toString() {
        return "Dog{" + "name='" + name + '\'' + ", sex='" + sex + '\'' + ", age=" + age + ", fur='" + fur + '\''
                + ", breed='" + breed + '\'' + ", weight=" + weight + ", height=" + height + '}';
    }

    public static class Builder {
        private final String name; // 名称
        private String sex; // 性别
        private int age; // 年龄
        private String fur; // 毛发
        private String breed; // 品种
        private float weight; // 体重
        private float height; // 身高

        public Builder(String name) {
            this.name = name;
        }

        public Builder sex(String sex) {
            this.sex = sex;
            return this;
        }

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

        public Builder fur(String fur) {
            this.fur = fur;
            return this;
        }

        public Builder breed(String breed) {
            this.breed = breed;
            return this;
        }

        public Builder weight(float weight) {
            this.weight = weight;
            return this;
        }

        public Builder height(float height) {
            this.height = height;
            return this;
        }

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

 

 

Client端代码

public class Client {
    public static void main(String args[]) {
        Dog dog = new Dog.Builder("花花").age(1).height(50.0f).weight(50.0f).sex("boy").breed("拉布拉多").fur("yellow")
                .build();
        System.out.println(dog.toString());
    }
}

 

 

参考：

https://blog.csdn.net/ctf_htj/article/details/18792799