创建学生类 有姓名 学校 和年龄 覆盖toString() 1放到集合ArrayList 然后 2在第2个位置插入1个学生信息 3判断 刘德华这个学生是否存在 存在就打出来, 4输出全部学生信息 直接打印对象

学生类

package com.lanxi.demo1;
public class Student {
    //创建属性  姓名，学校，年龄
    private String name;
    private String school;
    private int age;
    public Student(String name, String school, int age) {    //创建有参构造方法
        super();
        this.name = name;
        this.school = school;
        this.age = age;
    }
    //构造无参构造方法
    public Student() {
        super();
    }
    //重写toString方法
    @Override
    public String toString() {
        return "Student [name=" + name + ", school=" + school + ", age=" + age
                + "]";
    }
    //创建get,set方法
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSchool() {
        return school;
    }
    public void setSchool(String school) {
        this.school = school;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
}

测试类

package com.lanxi.demo1;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class Test {

    public static void main(String[] args) {
        List list=new ArrayList();
        list.add(new Student("张三","师大",18));
        list.add(new Student("李四","理工",20));
        list.add(new Student("王五","旅游",25));
        list.add(1, new Student("刘德华","旅游",35));
        //for循环遍历
        /*for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }*/
        //迭代便利
        Iterator it=list.iterator();
        while(it.hasNext()){
            Student stu=(Student)it.next();//强转
            //输出新建对象的全部信息（姓名，学校，年龄）
            System.out.println(stu);
            //判断“刘德华”是否存在
            if ("刘德华".equals(stu.getName())) {
                //找到对象
                System.out.println("it is exist");
            }else{
                //找不到对象
                System.out.println("no find");
            }
        }
    }
}

运行结果