第二条 一个类如果有多个参数，考虑用Builder构造者模式

1.

@Data
public class Student {
    //体检用
    private String name;
    private int age;
    private int height;
    private int sex;
    //录取用
    private String schoolName;
    private String profession;
    private int gradeNo;
    //分班用
    private String idCard;
    private String stuNo;
    private String labName;
    private String dormitoryAddress;

    private Student(Builder builder) {
        this.name = builder.name;
        this.age = builder.age;
        this.height = builder.height;
        this.sex = builder.sex;
        this.schoolName = builder.schoolName;
        this.profession = builder.profession;
        this.gradeNo = builder.gradeNo;
        this.idCard = builder.idCard;
        this.stuNo = builder.stuNo;
        this.labName = builder.labName;
        this.dormitoryAddress = builder.dormitoryAddress;
    }

    public static class Builder{
        //体检用 公用的用final
        private final String name;
        private final int age;
        private final int height;
        private final int sex;

        //录取用
        private String schoolName;
        private String profession;
        private int gradeNo;

        //分班用
        private String idCard;
        private String stuNo;
        private String labName;
        private String dormitoryAddress;

        public Builder(String name, int age, int height, int sex) {
            this.name = name;
            this.age = age;
            this.height = height;
            this.sex = sex ;
        }

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

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

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

        public Builder idCard (String idCard) {
            this.idCard = idCard;
            return  this;
        }
        public  Builder stuNo(String stuNo) {
            this.stuNo = stuNo;
            return this;
        }
        public Builder labName(String labName) {
            this.labName = labName;
            return  this;
        }

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

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

    //测试
    public static void main(String[] args) {
        //各取所需，公用的字段写成Builder的构造方法中！
        Student zhangsan = new Student.Builder("zhangsan", 28, 168, 0).build(); //体检的张三只要四个基本参数

        Student zhangsan1 = new Builder("zhangsan", 28, 168, 0).schoolName("安徽大学").profession("国贸").build(); // 录取学生信息管理系统要的字段

        Student zhangsan2  = new Student.Builder("zhangsan", 28, 168, 0).schoolName("安徽大学").profession("国贸").stuNo("学号04012057")
                            .gradeNo(302).dormitoryAddress("寝室号502").build();

        System.out.println("张三的体检信息：" + zhangsan);
        System.out.println("张三被录取后信息：" + zhangsan1);
        System.out.println("张三分班后：" + zhangsan2);

    }
}

2. 结果

张三的体检信息：Student(name=zhangsan, age=28, height=168, sex=0, schoolName=null, profession=null, gradeNo=0, idCard=null, stuNo=null, labName=null, dormitoryAddress=null)
张三被录取后信息：Student(name=zhangsan, age=28, height=168, sex=0, schoolName=安徽大学, profession=国贸, gradeNo=0, idCard=null, stuNo=null, labName=null, dormitoryAddress=null)
张三分班后：Student(name=zhangsan, age=28, height=168, sex=0, schoolName=安徽大学, profession=国贸, gradeNo=302, idCard=null, stuNo=学号04012057, labName=null, dormitoryAddress=寝室号502)