Java小例程------实现对象存入集合中、遍历、随机数做索引在集合中查找

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

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

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

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Random;

public class CallStudent {
public static void main(String[] args) {
ArrayList<Student> arr = new ArrayList<Student>();
addStudent(arr);
randomStudent(arr);
}

/*
* 随机数生成学生信息
*/
public static void randomStudent(ArrayList<Student> arr){
Random r = new Random();
int index = r.nextInt(arr.size());
Student s = arr.get(index);
printStudent(arr);
System.out.println(s.getName() + " 年龄是: " +s.getAge());
}

/*
* 遍历集合
*/
public static void printStudent(ArrayList<Student> arr){
for(int i=0 ; i<arr.size() ; i++){
Student s = arr.get(i);
System.out.println(s.getName() +"..."+ s.getAge());
}
}

/*
* 定义方法存储对象
*/
public static void addStudent(ArrayList<Student> arr){
Student s1 = new Student();
s1.setName("张三");
s1.setAge(15);

Student s2 = new Student();
s2.setName("张四");
s2.setAge(16);

Student s3 = new Student();
s3.setName("张五");
s3.setAge(17);

Student s4 = new Student();
s4.setName("张六");
s4.setAge(18);

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