Java封装Demo

╰半夏微凉° 2022-05-15 01:43 101阅读 0赞

模拟场景实现：  
某校开设“计算机科学与应用”专业，专业编号J0001，学制4年。 现有3名学生都报名学习了这个专业。  
![20180822141243.png][]  
代码逻辑：  
![20180823090139.png][]  
student类：

package com.geekmubai.moudel;
    
    public class Student {
        //成员属性：学号、姓名、性别、年龄
        private String studentNo;
        private String studentName;
        private String studentSex;
        private int studentAge;
    
        //无参构造方法
        public Student() {
    
        }
    
        //多参构造方法实现对全部属性的赋值
    
    
        public Student(String studentNo, String studentName, String studentSex, int studentAge) {
            this.setStudentNo(studentNo);
            this.setStudentName(studentName);
            this.setStudentSex(studentSex);
            this.setStudentAge(studentAge);
        }
    
        public String getStudentNo() {
            return studentNo;
        }
    
        public void setStudentNo(String studentNo) {
            this.studentNo = studentNo;
        }
    
        public String getStudentName() {
            return studentName;
        }
    
        public void setStudentName(String studentName) {
            this.studentName = studentName;
        }
    
        public String getStudentSex() {
            return studentSex;
        }
    
        public void setStudentSex(String studentSex) {
            if (studentSex !="男" && studentSex != "女" )
                this.studentSex = "男";
            else
                this.studentSex = studentSex;
        }
    
        public int getStudentAge() {
            return studentAge;
        }
    
        public void setStudentAge(int studentAge) {
            if (studentAge<10 || studentAge>100)
                this.studentAge = 18;
            else
                this.studentAge = studentAge;
        }
    
        //学生自我介绍的方法
        public String introduction(){
            String str = "学生信息如下：\n姓名：" + this.getStudentName()+ "\n学号：" + this.getStudentNo() + "\n性别：" + this.getStudentSex()+"\n年龄："+getStudentAge();
            return str;
        }
        //传入字符串
        public String introduction(String subjectName,int subjectLife){
            String str = "学生信息如下：\n姓名：" + this.getStudentName()+ "\n学号：" + this.getStudentNo() + "\n性别：" + this.getStudentSex()+"\n年龄："+getStudentAge()+ "\n专业：" + subjectName+"\n年限："+subjectLife;
            return str;
        }
        //传入对象
        public String introduction(Subject mySubject){
            String str = "学生信息如下：\n姓名：" + this.getStudentName()+ "\n学号：" + this.getStudentNo() + "\n性别：" + this.getStudentSex()+"\n年龄："+getStudentAge()+ "\n专业：" + mySubject.getSubjectName()+"\n年限："+mySubject.getSubjectLife();
            return str;
        }
    
    }

subject类

package com.geekmubai.moudel;
    
    public class Subject {
        //成员属性：学科名称、学科编号、学制年限、学生信息、报名的学生数
        private String subjectName;
        private String subjetcNo;
        private int subjectLife;
        private Student[] myStudents;
        private int studentNum;
    
        //无参构造方法
        public Subject() {
    
        }
    
        //带参构造，实现对学科名称、编号、学制年限的赋值
        public Subject(String subjectName, String subjectNo, int subjectLife) {
            //this赋值，调用成员属性 没有业务逻辑 不推荐
            //this.subjectName = subjectName;
            //推荐用下面的set方法赋值
            this.setSubjectName(subjectName);
            this.setSubjetcNo(subjectNo);
            this.setSubjectLife(subjectLife);
        }
        //带参构造，实现对属性的全部赋值
        public Subject(String subjectName, String subjectNo, int subjectLife,Student[] myStudents) {
            this.setSubjectName(subjectName);
            this.setSubjetcNo(subjectNo);
            this.setSubjectLife(subjectLife);
        }
    
        //get、set方法
        public String getSubjectName() {
            return subjectName;
        }
    
        public void setSubjectName(String subjectName) {
            this.subjectName = subjectName;
        }
    
        public String getSubjetcNo() {
            return subjetcNo;
        }
    
        public void setSubjetcNo(String subjetcNo) {
            this.subjetcNo = subjetcNo;
        }
    
        public int getSubjectLife() {
            return subjectLife;
        }
    
        public Student[] getMyStudents() {
            //数组初始化
            if (this.myStudents == null)
                this.myStudents = new Student[200];
            return myStudents;
        }
    
        public void setMyStudents(Student[] myStudents) {
            this.myStudents = myStudents;
        }
    
        public int getStudentNum() {
            return studentNum;
        }
    
        public void setStudentNum(int studentNum) {
            this.studentNum = studentNum;
        }
    
        //设置学制年限>0
        public void setSubjectLife(int subjectLife) {
            if (subjectLife <= 0)
                return;
            this.subjectLife = subjectLife;
        }
        //专业介绍的方法
        public String info() {
            String str = "专业信息如下：\n专业名称：" + this.getSubjectName() + "\n专业编号：" + this.getSubjetcNo() + "\n学制年限：" + this.getSubjectLife();
            return str;
        }
    
        // 1、将学生保存到数组中。
        // 2、将学生数保存到studentNum
        public void addStudent(Student stu){
            for (int i=0;i<this.getMyStudents().length;i++){
                if (this.getMyStudents()[i]==null){
                    this.getMyStudents()[i]=stu;
                    this.studentNum=i+1;
                    return;
                }
            }
        }
    }

测试类

package com.geekmubai.test;
    
    import com.geekmubai.moudel.Student;
    import com.geekmubai.moudel.Subject;
    
    public class SubjectTest {
        public static void main(String[] args) {
            //测试subject
            Subject sub = new Subject("计算机科学与技术","J0001",4);
            System.out.println(sub.info());
            System.out.println("=======================");
            //测试student
            Student stu = new Student("S01","慕白","男",20);
            System.out.println(stu.introduction());
            System.out.println("=======================");
            //新增student
            Student stu1 = new Student("S02","南宫","女",18);
            System.out.println(stu1.introduction("网络工程",4));
            System.out.println("=======================");
            Student stu2 = new Student("S03","刘严","女",18);
            System.out.println(stu2.introduction(sub));
            System.out.println("=======================");
            //测试指定专业报名人数
            sub.addStudent(stu);
            sub.addStudent(stu1);
            sub.addStudent(stu2);
            System.out.println(sub.getSubjectName()+"的专业已有"+sub.getStudentNum()+"人报名！");
        }
    }

[20180822141243.png]: /images/20220515/11aa9bf2c91e4565a2ea0345241359f2.png
[20180823090139.png]: /images/20220515/966a602590114b7fae2e4fad742f7f92.png