关于#java#的问题，如何解决？

Question

有什么问题
import java.util.ArrayList;

import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
//1.自定义Student类，创建5个Student对象，将其存储到集合中，进行遍历(所有方式)。
class Student{
String name;
int age;
int sid;
String xb;
String aiHao;

public Student(String name, int age, int sid, String xb, String aiHao) {
    this.name = name;
    this.age = age;
    this.sid = sid;
    this.xb = xb;
    this.aiHao = aiHao;
}

}
public class xsj2 {
public static void main(String[] args) {
List list = new ArrayList();
list.add(new Student("小明",18,10001,"男","打游戏"));
list.add(new Student("小强",19,10002,"男","打篮球"));
list.add(new Student("小丽",17,10003,"女","唱歌"));
list.add(new Student("张三",20,10004,"男","踢足球"));
list.add(new Student("小娟",19,10005,"女","弹钢琴"));
//集合转数组
Object[] objects = list.toArray();
for (int i = 0; i < objects.length; i++) {
System.out.println(objects[i]);
}

    //集合特有的方法遍历集合元素
    //通过iterator,返回的一个迭代器，迭代器可以迭代取出Collection中的元素
    Iterator it = list.iterator();//多态 接口类型的引用指向了自己的实现类对象
    while (it.hasNext()){
        System.out.println(it.next());
    }
   
    //for-each
    for (Object o : list) {
        System.out.println(o);
    }
  
    //普通for语句
    for (int i = 0; i < list.size(); i++) {
        System.out.println(list.get(i));
    }
    
    //列表迭代器 注意：仅限于List使用
    ListIterator lisyIt = list.listIterator();
    while (lisyIt.hasNext()) {
        Object obj = lisyIt.next();
        if (obj.equals("java02")) {
           /* lisyIt.add("999");//添加
            lisyIt.remove();//移除*/
            //lisyIt.set("999");//修改
        }
    }
    System.out.println(list);
}

private static class StudentList {
}

}

Answer 1

你这个代码实现没有什么问题。
主要两处有问题。
1.java类命名必须大写,并且类名与文件名相同
2.直接print对象输出的是对象地址,需要给类重写以下toString方法。
这是你的代码修改问题1以后的结果。

增加tostring方法后的结果。

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
public class Student {
    String name;
    int age;
    int sid;
    String xb;
    String aiHao;

    public Student(String name, int age, int sid, String xb, String aiHao) {
        this.name = name;
        this.age = age;
        this.sid = sid;
        this.xb = xb;
        this.aiHao = aiHao;
    }
    public String toString(){
        StringBuilder strB = new StringBuilder();
        strB.append("[姓名:").append(this.name)
            .append(",年龄:").append(this.age)
            .append(",学号:").append(this.sid)
            .append(",性别:").append(this.xb)
            .append(",爱好:").append(this.aiHao)
            .append("]");
        return strB.toString();
    }
    public static void main(String []args) {
        List list = new ArrayList();
        list.add(new Student("小明",18,10001,"男","打游戏"));
        list.add(new Student("小强",19,10002,"男","打篮球"));
        list.add(new Student("小丽",17,10003,"女","唱歌"));
        list.add(new Student("张三",20,10004,"男","踢足球"));
        list.add(new Student("小娟",19,10005,"女","弹钢琴"));
        //集合转数组
        Object[] objects = list.toArray();
        for (int i = 0; i < objects.length; i++) {
            System.out.println(objects[i]);
        }
    }
}