Java 入门20 ArrayList 小案例实践

2022-06-23 20:38:10 阅读：128 来源： 互联网

标签：Java String ArrayList list Student 20 public name

案例一删除成绩中不满住80分的成绩

package com.heima.StringDemo;

import java.util.ArrayList;

public class ArrayList3 {
    public static void main(String[] args) {
        //创建ArrayList 对象  并使用泛型指定整数
        ArrayList<Integer> list = new ArrayList();

        //添加同学的成绩
        list.add(98);
        list.add(77);
        list.add(66);
        list.add(89);
        list.add(79);
        list.add(50);
        list.add(100);

        //循环ArrayList
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
            //判断成绩是否低于80  低于80 则删除
            if (list.get(i) <=80) {
                list.remove(i);
                //从前面往后面删除  删除元素值后,后面的元素值要向前挪 所以i--;
                i--;
            }
        }

        //打印删除后的学生成绩
        System.out.println(list);
    }
}

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案例二影片信息在程序中的存储

Movie 类

package com.heima.StringDemo;

public class Movie {
    private String name;
    private double scores;
    private String filmPerson;

    //创造无参构造器

    public Movie() {
    }

    //创造有参构造器
    public Movie(String name, double scores, String filmPerson) {
        this.name = name;
        this.scores = scores;
        this.filmPerson = filmPerson;
    }

    //set get方法创建

    public String getName() {
        return name;
    }

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

    public double getScores() {
        return scores;
    }

    public void setScores(double scores) {
        this.scores = scores;
    }

    public String getFilmPerson() {
        return filmPerson;
    }

    public void setFilmPerson(String filmPerson) {
        this.filmPerson = filmPerson;
    }
}

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Test 测试类

package com.heima.StringDemo;

import java.util.ArrayList;
import java.util.Scanner;

/*
电影Test类
需求:定义电影类(名称,分值,演员),创建3个电影对象,代表散步影片,存入集合中并遍历
*/
public class Test {
    public static void main(String[] args) {
        //创造一个ArrayList 集合用来存储movies
        ArrayList<Movie> list = new ArrayList();
        Movie a = new Movie("肖申克的救赎", 9.7, "罗伯特");
        Movie b = new Movie("霸王别姬", 9.1, "虞姬");
        Movie c = new Movie("阿甘正传", 10.0, "阿甘");

        list.add(a);
        list.add(b);
        list.add(c);

        for (int i = 0; i < list.size(); i++) {
            Movie child=list.get(i);
            System.out.println(child.getName()+"评分"+child.getScores()+"主演"+child.getFilmPerson());
        }
    }
}

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案例三元素搜索

Student类

package com.heima.StringDemo;

public class Student {
    private String name;
    private int studentNum;
    private int age;
    private String studentClass;

    //创建有参构造器

    public Student(String name, int studentNum, int age, String studentClass) {
        this.name = name;
        this.studentNum = studentNum;
        this.age = age;
        this.studentClass = studentClass;
    }


    //创建无参构造器

    public Student() {
    }

    //get set 创建

    public String getName() {
        return name;
    }

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

    public double getStudentNum() {
        return studentNum;
    }

    public void setStudentNum(int studentNum) {
        this.studentNum = studentNum;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getStudentClass() {
        return studentClass;
    }

    public void setStudentClass(String studentClass) {
        this.studentClass = studentClass;
    }
}

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Test1 测试类

package com.heima.StringDemo;

import java.util.ArrayList;
import java.util.Scanner;

public class Test1 {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        //创建ArrayList 存储Student产生的对象
        ArrayList<Student> studentList = new ArrayList<>();

        //创建学生
        Student Stu = new Student("叶孤城", 20189812, 18, "二年级一班");
        Student Stu1 = new Student("东方不败", 20189813, 18, "二年级一班");
        Student Stu2 = new Student("西门吹雪", 20189814, 18, "二年级一班");
        Student Stu3 = new Student("梅超风", 20189815, 18, "二年级一班");

        //添加进StudentList
        studentList.add(Stu);
        studentList.add(Stu1);
        studentList.add(Stu2);
        studentList.add(Stu3);

        //循环展示studentList集合中的元素信息
        for (int i = 0; i < studentList.size(); i++) {
            Student child = studentList.get(i);
            System.out.println(child.getName() + "\t年纪 \t" + child.getAge() + "学号\t" + child.getStudentNum() + "年级\t" + child.getStudentClass());
        }
        while (true) {
            System.out.println("请输入学号");
            int num = sc.nextInt();
            Student s = getSearchMsg(studentList, num);
            if(s!=null){
                System.out.println(s.getName() + "\t年纪 \t" + s.getAge() + "学号\t" + s.getStudentNum() + "年级\t" + s.getStudentClass());
                System.out.println("查询完毕");
            }else{
                System.out.println("查无此人");
            }
            //查询结束
        }
    }

    public static Student getSearchMsg(ArrayList<Student> a, int num) {
        for (int i = 0; i < a.size(); i++) {
            Student child = a.get(i);
            //相同 则匹配上
            if (child.getStudentNum() == num) {
                return child;
            }
        }
        return null;//查无此学号
    }

}

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标签：Java,String,ArrayList,list,Student,20,public,name
来源： https://www.cnblogs.com/lvlisn/p/16406594.html

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Java 入门20 ArrayList 小案例实践