试编写一个教师类，教师有姓名、年龄、工资等属性，如果两个教师姓名、年龄和工资都相同，就认为是同一人，不能加入同一个集合，试用TreeSet类将若干教师信息保存并显示。

好的，以下是一个简单的教师类的示例代码：

import java.util.Objects;

public class Teacher implements Comparable<Teacher> {
    private String name;
    private int age;
    private double salary;

    public Teacher(String name, int age, double salary) {
        this.name = name;
        this.age = age;
        this.salary = salary;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public double getSalary() {
        return salary;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Teacher teacher = (Teacher) o;
        return age == teacher.age &&
                Double.compare(teacher.salary, salary) == 0 &&
                Objects.equals(name, teacher.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age, salary);
    }

    @Override
    public int compareTo(Teacher o) {
        if (this.equals(o)) {
            return 0;
        }
        int result = this.name.compareTo(o.getName());
        if (result == 0) {
            result = Integer.compare(this.age, o.getAge());
        }
        if (result == 0) {
            result = Double.compare(this.salary, o.getSalary());
        }
        return result;
    }

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

在这个示例中，教师类Teacher实现了Comparable接口，重写了equals()、hashCode()和compareTo()方法。其中，equals()和hashCode()方法用于判断两个教师对象是否相等；compareTo()方法用于将教师对象按照姓名、年龄、工资的顺序比较大小，以便于TreeSet类进行排序和去重。

下面是一个使用TreeSet类保存教师信息的示例代码：

import java.util.TreeSet;

public class TeacherTest {
    public static void main(String[] args) {
        TreeSet<Teacher> teacherSet = new TreeSet<>();
        Teacher teacher1 = new Teacher("Tom", 35, 5000);
        Teacher teacher2 = new Teacher("Jerry", 30, 4000);
        Teacher teacher3 = new Teacher("Tom", 35, 5000);
        Teacher teacher4 = new Teacher("Lucy", 28, 4500);
        Teacher teacher5 = new Teacher("Jerry", 35, 5000);

        teacherSet.add(teacher1);
        teacherSet.add(teacher2);
        teacherSet.add(teacher3);
        teacherSet.add(teacher4);
        teacherSet.add(teacher5);

        for (Teacher teacher : teacherSet) {
            System.out.println(teacher);
        }
    }
}

在这个示例中，我们创建了一个TreeSet<Teacher>对象teacherSet，然后向其中添加了五个教师对象。由于teacher1和teacher3、teacher2和teacher5具有相同的姓名、年龄和工资，因此它们会被TreeSet类自动去重。最后，我们使用for循环遍历teacherSet中的所有教师对象，并通过toString()方法输出它们的信息。