public class Main { public static void main(String[] args) { Map<String,Student>hashMap=new HashMap<>(); Student student=new Student("赵同学",30); Student student1=new Student("孙同学",18); Student student2=new Student("康同学",32); hashMap.put("赵同学",student); hashMap.put("孙同学",student1); hashMap.put("康同学",student2); System.out.println(hashMap); } } class Student { private String name; private int number; private Map<String,Integer>hashMap; private Map<String,Integer>hashMap1; public Student(String name,int number) { this.name=name; this.number=number; } public void putInfo(String key,String value) { } public String getName() { return name; } public int getNumber() { return number; } }这段代码想要输出信息应该如何更改

如果想要输出学生的姓名和学号，可以在Student类中添加toString方法，如下：

class Student {
    private String name;
    private int number;
    private Map<String,Integer>hashMap;
    private Map<String,Integer>hashMap1;
    public Student(String name,int number)
    {
        this.name=name;
        this.number=number;
    }
    public void putInfo(String key,String value) {
    }
    public String getName() {
        return name;
    }
    public int getNumber() {
        return number;
    }
    @Override
    public String toString() {
        return "name: " + name + ", number: " + number;
    }
}

然后在Main类中调用HashMap的toString方法即可输出每个学生的姓名和学号：

public static void main(String[] args) {
    Map<String,Student>hashMap=new HashMap<>();
    Student student=new Student("赵同学",30);
    Student student1=new Student("孙同学",18);
    Student student2=new Student("康同学",32);
    hashMap.put("赵同学",student);
    hashMap.put("孙同学",student1);
    hashMap.put("康同学",student2);
    System.out.println(hashMap.toString());
}

输出结果为：

{赵同学=name: 赵同学, number: 30, 孙同学=name: 孙同学, number: 18, 康同学=name: 康同学, number: 32}