for (Map.Entry<String, College> entry : colleges.entrySet()) { College college = entry.getValue(); List<ClassInfo> classList = college.getClasses(); for (ClassInfo classInfo : classList) { if (classInfo.hasStudent(studentId)) { Student student = classInfo.getStudent(studentId); System.out.println(student); return; } } }请帮我写出college，College类，student类，ClassInfo类

好的，以下是可能的代码实现：

College类：

public class College {
    private String name;
    private List<ClassInfo> classes;

    public College(String name, List<ClassInfo> classes) {
        this.name = name;
        this.classes = classes;
    }

    public String getName() {
        return name;
    }

    public List<ClassInfo> getClasses() {
        return classes;
    }
}

ClassInfo类：

public class ClassInfo {
    private String name;
    private List<Student> students;

    public ClassInfo(String name, List<Student> students) {
        this.name = name;
        this.students = students;
    }

    public String getName() {
        return name;
    }

    public List<Student> getStudents() {
        return students;
    }

    public boolean hasStudent(String studentId) {
        for (Student student : students) {
            if (student.getId().equals(studentId)) {
                return true;
            }
        }
        return false;
    }

    public Student getStudent(String studentId) {
        for (Student student : students) {
            if (student.getId().equals(studentId)) {
                return student;
            }
        }
        return null;
    }
}

Student类：

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

    public Student(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

其中，colleges是一个Map<String, College>类型的变量，存储了所有学校的信息，每个学校对应一个College对象，而每个College对象包含了若干个ClassInfo对象，每个ClassInfo对象包含了若干个Student对象。上述代码中的方法实现了根据给定的学生ID，从所有学校的所有班级中查找该学生的信息，并输出其信息。