Java学习之数据封装与引用对象的应用

偶然间发现了一种数据封装的新思想，记录一下：

简单说明一下：People是数据集合，Teacher和Student是People的属性，然后新建对象不是简简单单的new一个对象，而是通过“handler”灵活创建对象，更重要的可以根据实际情景进行业务处理。

Bean：

public class People {
    private int id;
    private Student student;
    private Teacher teacher;

    public People() {
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setStudent(Student student) {
        this.student = student;
    }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }

    public int getId() {
        return id;
    }

    public Student getStudent() {
        return student;
    }

    public Teacher getTeacher() {
        return teacher;
    }

    @Override
    public String toString() {
        return "People{" +
                "id=" + id +
                ", student=" + student +
                ", teacher=" + teacher +
                '}';
    }
}

public class Teacher {
    private int id;
    private String name;

    public Teacher(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public void setId(int id) {
        this.id = id;
    }

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

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

public class Student {
    private int id;
    private String name;

    public Student(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public void setId(int id) {
        this.id = id;
    }

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

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

接口：

public interface HandlerInterface {
    public void getObject(People people);
}

实现类：

public class TeacherHandler implements HandlerInterface {
    @Override
    public void getObject(People people) {
        Teacher teacher = selectById(people.getId());
        people.setTeacher(teacher);
    }

    //随便赋值模仿数据库查询
    private Teacher selectById(int id) {
        return new Teacher(id, "teacher");
    }


}

public class StudentHandler implements HandlerInterface {

    @Override
    public void getObject(People people) {
        Student student = selectById(people.getId());
        people.setStudent(student);
    }

    //随便赋值模仿数据库查询
    private Student selectById(int id) {
        return new Student(id, "student");
    }
}

工具类：

public class Handler {
    private static List<HandlerInterface> handlerList = new ArrayList<>(4);

    static {
        initHandler();
    }

    private static void initHandler() {
        handlerList.add(new TeacherHandler());
        handlerList.add(new StudentHandler());
    }

    public static List<HandlerInterface> getHandler() {
        return handlerList;
    }
}

测试：

public class Test {
    public static void main(String[] args) {
        People people = new People();
        people.setId(1);
        List<HandlerInterface> handlerList = Handler.getHandler();
        for (HandlerInterface handler : handlerList) {
            handler.getObject(people);
        }

        System.out.println(people);
    }
}