Java设计模式<建造者模式>

Java设计模式<建造者模式>

意图

将一个复杂的构建与其表示相分离，使得同样的构建过程可以创建不同的表示。
解决原子操作不经常变化，而组合经常变化

优点

建造者独立，易扩展
便于控制细节风险

缺点

原子操作必须有共同点，有范围限制
如果变化复杂，就会有很多建造者类

现实生活场景

主要介绍一下通过builder实现流式编程

应用场景

目前是SOA兴起的时代，所以各个模块之间API调用，通过在接口层面实现参数的校验

Demo 创建一个Person类

public class Person {

    private final String name;

    private final float height;

    private final int weight;

    public static Builder param() {
        return new Builder();
    }

    public Person(Builder builder) {
        this.name = builder.name;
        this.height = builder.height;
        this.weight = builder.weight;
    }

    public String getName() {
        return name;
    }

    public float getHeight() {
        return height;
    }

    public int getWeight() {
        return weight;
    }

    static class Builder {
        private String name;

        private float height;

        private int weight;

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

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

        public Builder setWeight(int weight) {
            this.weight = weight;
            return this;
        }
        public Person build(){
            if(null == name || "".equals(name)){
                throw new IllegalArgumentException("name can not be null");
            }
            return new Person(this);
        }
    }


}

测试类

public class DemoMain2 {
    public static void main(String[] args) {
        Person person = Person.param().
                setName("jeffy").
                setHeight(180l).
                setWeight(75)
                .build();
    }
}