使用java编写程序，使用TreeSet存储教室对象，教室对象包括教室号no,教室地址 address,教室容纳人数 count,使用教室号排序。遍历TreeSet.

以下是使用Java编写程序，使用TreeSet存储教室对象，遍历TreeSet并按照教室号排序的示例代码：

import java.util.*;

public class Classroom implements Comparable<Classroom> {
    private String no;
    private String address;
    private int count;

    public Classroom(String no, String address, int count) {
        this.no = no;
        this.address = address;
        this.count = count;
    }

    public String getNo() {
        return no;
    }

    public String getAddress() {
        return address;
    }

    public int getCount() {
        return count;
    }

    @Override
    public int compareTo(Classroom o) {
        return this.no.compareTo(o.getNo());
    }

    public static void main(String[] args) {
        Set<Classroom> classrooms = new TreeSet<>();
        classrooms.add(new Classroom("A101", "Main Building", 50));
        classrooms.add(new Classroom("A102", "Main Building", 60));
        classrooms.add(new Classroom("B101", "Science Building", 70));
        classrooms.add(new Classroom("C201", "Engineering Building", 80));

        for (Classroom classroom : classrooms) {
            System.out.println(classroom.getNo() + " " + classroom.getAddress() + " " + classroom.getCount());
        }
    }
}

在这个示例中，我们定义了一个`Classroom`类，实现了`Comparable`接口以便可以按照教室号进行排序。我们创建了一个`TreeSet`对象来存储`Classroom`对象，并添加了一些示例数据。最后，我们使用for-each循环遍历`TreeSet`并输出每个对象的教室号、地址和容纳人数。由于`TreeSet`会自动按照教室号进行排序，因此我们可以保证输出的顺序是按照教室号排序的。