java实战训练

案例 学生信息系统

需求

展示数据，并按照学号完成搜索
学生类信息（学号，姓名，性别，班级）
测试数据：
20180302，叶孤城，23，护理一班
20180303，东方不败，23，推拿二班
20180304，西门吹雪，26，中药学四班
20180305，梅超风，26，神经科二班

public class ArrayListTest6 {
    public static void main(String[] args) {
        //1.定义学生类，后期用于创建对象封装学生数据

        //2.定义集合对象用于装学生对象
        ArrayList<Student> students = new ArrayList<>();
        students.add(new Student("20180302", "叶孤城", 23, "护理一班"));
        students.add(new Student("20180303", "东方不败", 23, "推拿二班"));
        students.add(new Student("20180304", "西门吹雪", 26, "中药学四班"));
        students.add(new Student("20180305", "梅超风", 26, "神经科二班"));

        //3.遍历集合中每个学生对象展示其数据
        for (int i = 0; i < students.size(); i++) {
            Student student = students.get(i);
            System.out.println("学号:" + student.getStudyId() + "姓名：" + student.getName() +
                    "年龄" + student.getAge() + "班级：" + student.getClassName());
        }

        //4.让用户不断地输入学号，可以搜索出该学生对象信息并展示出来（独立成方法）
        Scanner sc = new Scanner(System.in);
        System.out.println("请您输入要查询的学生的学号！");
        String Id = sc.next();
        Student s = getStudentByStudyId(students, Id);
        if (s == null) {
            System.out.println("查无此人！");
        } else {
            System.out.println(s.getStudyId() + s.getName() + s.getAge() + s.getClassName());
        }
    }

    //根据学号去集合找出学生对象并返回。
    public static Student getStudentByStudyId(ArrayList<Student> students, String studyId) {
        for (int i = 0; i < students.size(); i++) {
            Student s = students.get(i);
            if (s.getStudyId().equals(studyId)) {
                return s;
            }
        }
        return null;//查无此学号！
    }
}
public class Student {
    private String studyId;
    private String name;
    private int age;
    private String className;

    public Student() {
    }//标准javabean一定要有无参构造器

    public Student(String studyId, String name, int age, String className) {
        this.studyId = studyId;
        this.name = name;
        this.age = age;
        this.className = className;
    }

    public String getStudyId() {
        return studyId;
    }

    public void setStudyId(String studyId) {
        this.studyId = studyId;
    }

    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 String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }
}

总结

• 这里体现了封装的方便，面向对象的编程。同时在实现一个独立功能时尽量采用方法去实现