数据文件中读出各药品的信息记录，存储在顺序表中。各药品的信息包括：药品编号、药名、药品单价、销出数量、销售额。药品编号共4位，采用字母和数字混合编号，如：A125，前一位为大写字母，后三位为数字，按药品编号进行排序时，可采用多种排序法。对各药品的单价、销售量或销售额进行排序时，可采用多种排序方法，如直接插入排序、冒泡排序、快速排序，直接选择排序等方法。在本系统中，对单价的排序采用冒泡排序法，对销售量的排序采用快速排序法，对销售额的排序采用堆排序法。

好的，这是一个非常具体的问题，以下是可能的Java代码实现：

药品类：

public class Medicine {
    private String medNo;  //药品编号
    private String medName;  //药名
    private double price;  //药品单价
    private int quantity;  //销出数量
    private double sales;  //销售额

    public Medicine(String medNo, String medName, double price, int quantity, double sales) {
        this.medNo = medNo;
        this.medName = medName;
        this.price = price;
        this.quantity = quantity;
        this.sales = sales;
    }

    public String getMedNo() {
        return medNo;
    }

    public String getMedName() {
        return medName;
    }

    public double getPrice() {
        return price;
    }

    public int getQuantity() {
        return quantity;
    }

    public double getSales() {
        return sales;
    }
}

顺序表类：

public class MedicineList {
    private Medicine[] data;  //存储药品信息的数组
    private int size;  //顺序表实际长度

    public MedicineList(int maxSize) {
        data = new Medicine[maxSize];
        size = 0;
    }

    //按药品编号排序
    public void sortByMedNo() {
        for (int i = 0; i < size - 1; i++) {
            for (int j = 0; j < size - 1 - i; j++) {
                if (data[j].getMedNo().compareTo(data[j + 1].getMedNo()) > 0) {
                    Medicine temp = data[j];
                    data[j] = data[j + 1];
                    data[j + 1] = temp;
                }
            }
        }
    }

    //按单价排序
    public void sortByPrice() {
        for (int i = 0; i < size - 1; i++) {
            for (int j = 0; j < size - 1 - i; j++) {
                if (data[j].getPrice() > data[j + 1].getPrice()) {
                    Medicine temp = data[j];
                    data[j] = data[j + 1];
                    data[j + 1] = temp;
                }
            }
        }
    }

    //按销售量排序
    public void sortByQuantity() {
        quickSortQuantity(data, 0, size - 1);
    }

    //快速排序
    private void quickSortQuantity(Medicine[] array, int low, int high) {
        if (low < high) {
            int pivot = partitionQuantity(array, low, high);
            quickSortQuantity(array, low, pivot - 1);
            quickSortQuantity(array, pivot + 1, high);
        }
    }

    private int partitionQuantity(Medicine[] array, int low, int high) {
        int pivot = array[low].getQuantity();
        while (low < high) {
            while (low < high && array[high].getQuantity() >= pivot) {
                high--;
            }
            array[low] = array[high];
            while (low < high && array[low].getQuantity() <= pivot) {
                low++;
            }
            array[high] = array[low];
        }
        array[low] = new Medicine("", "", pivot, 0, 0);
        return low;
    }

    //按销售额排序
    public void sortBySales() {
        heapSortSales(data);
    }

    //堆排序
    private void heapSortSales(Medicine[] array) {
        int n = array.length;
        for (int i = n / 2 - 1; i >= 0; i--) {
            heapifySales(array, n, i);
        }
        for (int i = n - 1; i >= 0; i--) {
            Medicine temp = array[0];
            array[0] = array[i];
            array[i] = temp;
            heapifySales(array, i, 0);
        }
    }

    private void heapifySales(Medicine[] array, int n, int i) {
        int largest = i;
        int l = 2 * i + 1;
        int r = 2 * i + 2;
        if (l < n && array[l].getSales() > array[largest].getSales()) {
            largest = l;
        }
        if (r < n && array[r].getSales() > array[largest].getSales()) {
            largest = r;
        }
        if (largest != i) {
            Medicine temp = array[i];
            array[i] = array[largest];
            array[largest] = temp;
            heapifySales(array, n, largest);
        }
    }

    //添加药品信息
    public void addMedicine(Medicine medicine) {
        data[size++] = medicine;
    }

    //输出药品信息
    public void print() {
        for (int i = 0; i < size; i++) {
            System.out.println(data[i].getMedNo() + "\t" + data[i].getMedName() + "\t" + data[i].getPrice() + "\t" + data[i].getQuantity() + "\t" + data[i].getSales());
        }
    }
}

主程序：

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        MedicineList medicineList = new MedicineList(100);
        try {
            Scanner scanner = new Scanner(new File("data.txt"));
            while (scanner.hasNext()) {
                String line = scanner.nextLine();
                String[] fields = line.split(",");
                String medNo = fields[0];
                String medName = fields[1];
                double price = Double.parseDouble(fields[2]);
                int quantity = Integer.parseInt(fields[3]);
                double sales = Double.parseDouble(fields[4]);
                Medicine medicine = new Medicine(medNo, medName, price, quantity, sales);
                medicineList.addMedicine(medicine);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        //按药品编号排序
        medicineList.sortByMedNo();
        System.out.println("按药品编号排序：");
        medicineList.print();
        //按单价排序
        medicineList.sortByPrice();
        System.out.println("按单价排序：");
        medicineList.print();
        //按销售量排序
        medicineList.sortByQuantity();
        System.out.println("按销售量排序：");
        medicineList.print();
        //按销售额排序
        medicineList.sortBySales();
        System.out.println("按销售额排序：");
        medicineList.print();
    }
}

注：假设数据文件名为"data.txt"，每行格式为"药品编号,药名,药品单价,销出数量,销售额"。