实验内容

• 学生信息录入，信息包括学号、姓名、专业、四门课成绩、总分、名次；
• 系统可对学生信息浏览、增加、删除和修改；
• 按学生成绩确定名次及信息输出，双向冒泡排序、希尔排序、快速排序、堆排序。
• 要求可对学生信息查询，根据学号或姓名进行查找；
• 信息修改仅可修改四门课成绩；
• 文件存取学生信息。

项目分析

• 新增学生信息（包括学号、姓名、专业、4门课成绩……）
• 浏览学生信息（对学生排序后信息进行浏览）
• 删除学生信息（删除指定学生的信息，可给用户选择检索指定项）
• 查找学生信息（查找符合条件的某条记录）
• 保存学生信息（保存学生成绩档案信息到文本文件）
• 加载学生信息（登录系统后将磁盘文件中保存的学生成绩信息读取到内存中）

编程语言的选择

• 编程语言：Java
• 编译环境：JDK1.8
• 开发工具：IntelliJ IDEA

项目思路

基本类构建

1.学生类

代码实现如下：

package com.igeek.pojo;

import java.util.Objects;

/**
 * @author 86183
 * @ClassName: IntelliJ IDEA
 * @Description:
 * @date 2021/3/1 11:01
 */
public class Student_Node {

    private int id;
    private String name;
    private String major;
    private double math_grade;
    private double english_grade;
    private double java_grade;
    private double cpp_grade;
    private double all_grade;
    private int sort;

    public Student_Node() {
    }

    public Student_Node(int id, String name, String major, double math_grade,
                        double english_grade, double java_grade, double cpp_grade,
                        double all_grade, int sort) {
        this.id = id;
        this.name = name;
        this.major = major;
        this.math_grade = math_grade;
        this.english_grade = english_grade;
        this.java_grade = java_grade;
        this.cpp_grade = cpp_grade;
        this.all_grade = all_grade;
        this.sort = sort;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }

    public double getMath_grade() {
        return math_grade;
    }

    public void setMath_grade(double math_grade) {
        this.math_grade = math_grade;
    }

    public double getEnglish_grade() {
        return english_grade;
    }

    public void setEnglish_grade(double english_grade) {
        this.english_grade = english_grade;
    }

    public double getJava_grade() {
        return java_grade;
    }

    public void setJava_grade(double java_grade) {
        this.java_grade = java_grade;
    }

    public double getCpp_grade() {
        return cpp_grade;
    }

    public void setCpp_grade(double cpp_grade) {
        this.cpp_grade = cpp_grade;
    }

    public void setAll_grade() {
        this.all_grade = this.math_grade + this.english_grade + this.java_grade + this.cpp_grade;
    }

    public double getAll_grade() {
        return all_grade;
    }

    public int getSort() {
        return sort;
    }

    public void setSort(int sort) {
        this.sort = sort;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Student_Node that = (Student_Node) o;
        return id == that.id &&
                Double.compare(that.math_grade, math_grade) == 0 &&
                Double.compare(that.english_grade, english_grade) == 0 &&
                Double.compare(that.java_grade, java_grade) == 0 &&
                Double.compare(that.cpp_grade, cpp_grade) == 0 &&
                Double.compare(that.all_grade, all_grade) == 0 &&
                Double.compare(that.sort, sort) == 0 &&
                Objects.equals(name, that.name) &&
                Objects.equals(major, that.major);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, name, major, math_grade, english_grade,
                java_grade, cpp_grade, all_grade, sort);
    }

    @Override
    public String toString() {
        return id + "\t" + name + "\t" + major + "\t" + math_grade + "\t" + english_grade + "\t" +
                java_grade + "\t" + cpp_grade + "\t" + all_grade + "\t" + sort;
    }
}

2.基本功能类

3.排序类

（1）双向冒泡排序

代码实现如下：

package com.igeek.sort;

import com.igeek.pojo.Student_Node;

import java.util.ArrayList;

/**
 * @author 86183
 * @ClassName: IntelliJ IDEA
 * @Description:
 * @date 2021/3/1 11:14
 */
public class Bidirectional_bubble_Sort {
    /**
     * 根据总成绩排序
     *
     * @param list
     */
    public void sortByAll(ArrayList<Student_Node> list) {
        boolean needNextPass = true;
        for (int i = 0, j; i < list.size() / 2 && needNextPass; i++) {
            needNextPass = false;
            // 正向排序
            for (j = i; j < list.size() - 1 - i; j++) {
                if (list.get(j).getAll_grade() < list.get(j + 1).getAll_grade()) {
                    Student_Node student = list.get(j);
                    list.set(j, list.get(j + 1));
                    list.set(j + 1, student);
                    needNextPass = true;
                }
            }
            // 反向排序
            for (--j; j > i; j--) {
                if (list.get(j).getAll_grade() > list.get(j - 1).getAll_grade()) {
                    Student_Node student = list.get(j);
                    list.set(j, list.get(j - 1));
                    list.set(j - 1, student);
                    needNextPass = true;
                }
            }
        }
        for (Student_Node s : list) {
            s.setSort(list.indexOf(s) + 1);
        }
    }
}

（2）希尔排序

代码实现如下：

package com.igeek.sort;

import com.igeek.pojo.Student_Node;

import java.util.ArrayList;

/**
 * @author 86183
 * @ClassName: IntelliJ IDEA
 * @Description:
 * @date 2021/3/1 14:23
 */
public class Shell_Sort {
    /**
     * 根据总成绩排序
     *
     * @param list
     */
    public void sortByAll(ArrayList<Student_Node> list) {
        for (int gap = (int) Math.floor((list.size()) / 2); gap > 0; gap = (int) Math.floor(gap / 2)) {
            for (int i = gap; i < list.size(); i++) {
                int j = i;
                double value = list.get(i).getAll_grade();
                Student_Node student = list.get(i);
                while (j - gap >= 0 && value > list.get(j - gap).getAll_grade()) {
                    list.set(j, (list.get(j - gap)));
                    j = j - gap;
                }
                list.set(j, student);
            }
        }
        for (Student_Node s : list) {
            s.setSort(list.indexOf(s) + 1);
        }
    }
}

（3）快速排序

代码实现如下：

package com.igeek.sort;

import com.igeek.pojo.Student_Node;

import java.util.ArrayList;

/**
 * @author 86183
 * @ClassName: IntelliJ IDEA
 * @Description:
 * @date 2021/3/1 14:36
 */
public class Quick_Sort {
    /**
     * 根据总成绩排序
     *
     * @param list
     * @param low
     * @param high
     */
    public void sortByAll(ArrayList<Student_Node> list, int low, int high) {
        int i, j;
        Student_Node student;
        double temp;
        if (low > high) {
            return;
        }
        i = low;
        j = high;
        //temp就是基准位
        temp = list.get(low).getAll_grade();
        while (i < j) {
            //先看右边，依次往左递减
            while (temp >= list.get(j).getAll_grade() && i < j) {
                j--;
            }
            //再看左边，依次往右递增
            while (temp <= list.get(i).getAll_grade() && i < j) {
                i++;
            }
            //如果满足条件则交换
            if (i < j) {
                student = list.get(j);
                list.set(j, list.get(i));
                list.set(i, student);
            }

        }
        //最后将基准为与i和j相等位置的数字交换
        student = list.get(low);
        list.set(low, list.get(i));
        list.set(i, student);
        //递归调用左半数组
        sortByAll(list, low, j - 1);
        //递归调用右半数组
        sortByAll(list, j + 1, high);
        for (Student_Node s : list) {
            s.setSort(list.indexOf(s) + 1);
        }
    }
}

（4）堆排序

代码实现如下：

package com.igeek.sort;

import com.igeek.pojo.Student_Node;

import java.util.ArrayList;

/**
 * @author 86183
 * @ClassName: IntelliJ IDEA
 * @Description:
 * @date 2021/3/1 14:47
 */
public class Heap_Sort {
    /**
     * 堆排序
     * 根据总成绩排序
     */
    public void sortByAll(ArrayList<Student_Node> list) {
        //一次调整，最大值到了根节点
        for (int i = (list.size() - 1 - 1) / 2; i >= 0; i--) {//i相当于start
            adjust(list, i, list.size() - 1);
        }
        //最后一个值与根节点交换
        Student_Node student = new Student_Node();
        for (int j = 0; j < list.size() - 1; j++) {
            student = list.get(0);
            list.set(0, list.get(list.size() - 1 - j));
            list.set(list.size() - 1 - j, student);
            adjust(list, 0, list.size() - 1 - 1 - j);//调整最大的树
        }
        for (Student_Node s : list) {
            s.setSort(list.indexOf(s) + 1);
        }
    }

    public static void adjust(ArrayList<Student_Node> list, int start, int end) {

        Student_Node student = list.get(start);
        //一次调整过程
        for (int i = 2 * start + 1; i <= end; i = 2 * i + 1) {
            //找到左右孩子的最大值
            if (i < end && list.get(i).getAll_grade() > list.get(i + 1).getAll_grade()) {
                i++;  //最大值下标
            }
            if (list.get(i).getAll_grade() < student.getAll_grade()) {
                list.set(start, list.get(i));    //设置第start个位置元素的值
                start = i;
            }
            if (list.get(i).getAll_grade() > student.getAll_grade()) {
                break;
            }
        }
        list.set(start, student);
    }

}

4.文件交互类

（1）读取文件

（2）保存文件

5.主类