用java完成以下需求 创建一个表示学生的类Student，封装所有属性。包括“姓名(name)”、“学号(studentNum)”、“班级(classNumber)”、“性别(sex)”、“年龄(age)”、 “性格(nature)”，以及所有属性的get、set方法。另加一个重写public String toString（）方法把Student类对象的所有属性信息组合成一个字符串，并创建测试类实现该需求。

好的，以下是Java代码实现：

public class Student {
    private String name;
    private String studentNum;
    private String classNumber;
    private String sex;
    private int age;
    private String nature;

    public Student(String name, String studentNum, String classNumber, String sex, int age, String nature) {
        this.name = name;
        this.studentNum = studentNum;
        this.classNumber = classNumber;
        this.sex = sex;
        this.age = age;
        this.nature = nature;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getStudentNum() {
        return studentNum;
    }

    public void setStudentNum(String studentNum) {
        this.studentNum = studentNum;
    }

    public String getClassNumber() {
        return classNumber;
    }

    public void setClassNumber(String classNumber) {
        this.classNumber = classNumber;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getNature() {
        return nature;
    }

    public void setNature(String nature) {
        this.nature = nature;
    }

    @Override
    public String toString() {
        return "姓名：" + name +
                "，学号：" + studentNum +
                "，班级：" + classNumber +
                "，性别：" + sex +
                "，年龄：" + age +
                "，性格：" + nature;
    }
}

测试类实现：

public class TestStudent {
    public static void main(String[] args) {
        Student student = new Student("小明", "20210001", "1班", "男", 18, "开朗");
        System.out.println(student.toString());
    }
}

输出结果为：

姓名：小明，学号：20210001，班级：1班，性别：男，年龄：18，性格：开朗