java 设计模式

设计模式之建造者模式

对象多个属性，但实例化只用部分属性，减少构造器个数

 实例：实例化一个 21 岁的 王五 和 一个 22 岁的 数学老师

class Teacher{

    private String name;
    private Integer id;
    private String teach;
    static class TechersBuilt{

        private String name;
        private Integer id;
        private String teach;

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

        public TechersBuilt setId(Integer id) {
            this.id = id;
            return this;
        }

        public TechersBuilt setTeach(String teach) {
            this.teach = teach;
            return this;
        }

        public Teacher TechersBuilt(){
            return new Teacher(this);
        }
    }

    public Teacher(TechersBuilt techersBuilt){
        this.name = techersBuilt.name;
        this.id = techersBuilt.id;
        this.teach = techersBuilt.teach;
    }

    public String getName() {
        return name;
    }

    public Integer getId() {
        return id;
    }

    public String getTeach() {
        return teach;
    }
}

public class TeacherBuilder {
    public static void main(String[] args) {
        Teacher t1 = new Teacher.TechersBuilt().setId(21).setName("王五").TechersBuilt();
        Teacher t2 = new Teacher.TechersBuilt().setId(22).setTeach("数学").TechersBuilt();

        System.out.println(t1.getName());

    }
}