lombok @Builder實現原理

public class Person {

    private Person(Builder builder) {
        name = builder.name;
        age = builder.age;
    }

    private String name;
    private int age;

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }


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

    public static class Builder {
        private String name;
        private int age;

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

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

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

}

測試一下

public static void main(String[] args) {
        Person p = Person.builder().name("hehe").age(3).build();
        System.out.println(p);
    }