定义一个学生类Student，成员变量包括姓名、性别、年龄、语文成绩、数学成绩和英语成绩，成员方法包括getXXX方法、setXXX方法、求总和、求平均分。根据类Student的定义，创建5个该类的对象，输出每个学生的信息，计算并输出这5个学生成绩的总分和平均值。

在Java中，我们可以按照以下步骤定义一个`Student`类，并完成所需的功能：

public class Student {
    // 成员变量
    private String name;
    private String gender;
    private int age;
    private double chineseScore;
    private double mathScore;
    private double englishScore;

    // 构造函数
    public Student(String name, String gender, int age, double chineseScore, double mathScore, double englishScore) {
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.chineseScore = chineseScore;
        this.mathScore = mathScore;
        this.englishScore = englishScore;
    }

    // getXXX方法
    public String getName() {
        return name;
    }
    public String getGender() {
        return gender;
    }
    public int getAge() {
        return age;
    }
    public double getChineseScore() {
        return chineseScore;
    }
    public double getMathScore() {
        return mathScore;
    }
    public double getEnglishScore() {
        return englishScore;
    }

    // setXXX方法
    public void setName(String name) {
        this.name = name;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public void setChineseScore(double chineseScore) {
        this.chineseScore = chineseScore;
    }
    public void setMathScore(double mathScore) {
        this.mathScore = mathScore;
    }
    public void setEnglishScore(double englishScore) {
        this.englishScore = englishScore;
    }

    // 求总和方法
    public double getTotalScore() {
        return chineseScore + mathScore + englishScore;
    }

    // 求平均分方法
    public double getAverageScore() {
        if (chineseScore + mathScore + englishScore != 0) {
            return (totalScore / 3);
        } else {
            return 0; // 防止除数为零的情况
        }
    }

    // 主要用于演示，打印学生信息
    @Override
    public String toString() {
        return "Name: " + name + ", Gender: " + gender + ", Age: " + age +
                ", Chinese Score: " + chineseScore + ", Math Score: " + mathScore +
                ", English Score: " + englishScore + ", Total Score: " + getTotalScore() +
                ", Average Score: " + getAverageScore();
    }
}

// 创建并操作5个Student对象
public static void main(String[] args) {
    Student student1 = new Student("张三", "男", 18, 90, 85, 95);
    Student student2 = new Student("李四", "女", 17, 88, 90, 92);
    Student student3 = new Student("王五", "男", 16, 92, 88, 93);
    Student student4 = new Student("赵六", "女", 19, 95, 89, 90);
    Student student5 = new Student("孙七", "男", 17, 90, 92, 88);

    System.out.println("Students information:");
    System.out.println(student1);
    System.out.println(student2);
    System.out.println(student3);
    System.out.println(student4);
    System.out.println(student5);

    double totalScore = student1.getTotalScore() + student2.getTotalScore() + student3.getTotalScore() + 
                        student4.getTotalScore() + student5.getTotalScore();
    double averageScore = (totalScore / 5);
    
    System.out.println("\nTotal scores: " + totalScore);
    System.out.println("Average score: " + averageScore);
}

当运行这个`main`函数时，它会创建五个`Student`对象，并分别输出他们的信息以及所有学生的总分和平均分。