Java_7.1 ArrayList应用点名器

1.ArrayList同样可以添加自定义的类

将学生类添加到ArrayList集合中，其中学生类包括学生姓名，年龄

自定义学生类

package demo1;

public class Student {
	String name;
	int age;
}

将学生类添加到ArrayList集合中

package demo1;

import java.util.ArrayList;
import java.util.Random;

public class Demo1 {
	public static void main(String[] args) {
		ArrayList<Student> array = new ArrayList<Student>();   //定义ArrayList集合来盛放Student类
		add(array);                            //添加数据到集合中
		printArrayList(array);                    //打印集合数据
	}
 //打印集合数据
	public static void printArrayList(ArrayList<Student> array) {
		for (int i = 0; i < array.size(); i++) {
			Student s = array.get(i);
			System.out.println(s.name+"\t"+s.age);
		}
	}
  //添加数据到集合中
	public static void add(ArrayList<Student> array) {
		Student s1 = new Student();
		s1.name = "张三";
		s1.age = 23;

		Student s2 = new Student();
		s2.name = "李四";
		s2.age= 24;

		array.add(s1);
		array.add(s2);
	}
}

2.学生的随机点名器

先添加学生类

package demo1;

import java.util.ArrayList;
import java.util.Random;

public class Demo1 {
	public static void main(String[] args) {
		ArrayList<Student> array = new ArrayList<Student>();
		addStudent(array);
		printArrayList(array);
		randomStudent(array);
	}
	//生成随机数，选择对应的学生，打印姓名和年龄
	public static void randomStudent(ArrayList<Student> array) {
		Random ran = new Random();
		int index = ran.nextInt(array.size());
		Student s = array.get(index);
		System.out.println("选择的学生是："+s.name+"\n年龄为："+s.age);
	}
	//打印集合
	public static void printArrayList(ArrayList<Student> array) {
		for (int i = 0; i < array.size(); i++) {
			Student s = array.get(i);
			System.out.println(s.name+"\t"+s.age);
		}
	}
	//向集合中添加Student数据
	public static void addStudent(ArrayList<Student> array) {
		Student s1 = new Student();
		s1.name = "张三";
		s1.age = 23;

		Student s2 = new Student();
		s2.name = "李四";
		s2.age = 24;

		Student s3 = new Student();
		s3.name = "王五";
		s3.age = 25;

		Student s4 = new Student();
		s4.name = "马六";
		s4.age = 26;

		array.add(s1);
		array.add(s2);
		array.add(s3);
		array.add(s4);
	}
}