java编程编码图书进销存管理系统的功能结构如图2-1所示。主要功能如下。 （1）采购管理：采购管理主要记录图书采购信息，管理员登录系统后，可依实际采购情况添加新的采购单，将图书信息入库。另外还可以按月查看历史采购信息。

Java编程实现图书进销存管理系统的采购管理功能的代码如下：

1. 定义Purchase类，用于记录图书采购信息

public class Purchase {
    private String purchaseID; // 采购单号
    private Date purchaseDate; // 采购日期
    private String purchaser; // 采购员
    private String supplier; // 供应商
    private String bookName; // 图书名称
    private int bookQuantity; // 图书数量
    private double bookPrice; // 图书单价

    // 构造函数
    public Purchase(String purchaseID, Date purchaseDate, String purchaser, String supplier, String bookName, int bookQuantity, double bookPrice) {
        this.purchaseID = purchaseID;
        this.purchaseDate = purchaseDate;
        this.purchaser = purchaser;
        this.supplier = supplier;
        this.bookName = bookName;
        this.bookQuantity = bookQuantity;
        this.bookPrice = bookPrice;
    }

    // getter和setter方法
    public String getPurchaseID() {
        return purchaseID;
    }

    public void setPurchaseID(String purchaseID) {
        this.purchaseID = purchaseID;
    }

    public Date getPurchaseDate() {
        return purchaseDate;
    }

    public void setPurchaseDate(Date purchaseDate) {
        this.purchaseDate = purchaseDate;
    }

    public String getPurchaser() {
        return purchaser;
    }

    public void setPurchaser(String purchaser) {
        this.purchaser = purchaser;
    }

    public String getSupplier() {
        return supplier;
    }

    public void setSupplier(String supplier) {
        this.supplier = supplier;
    }

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public int getBookQuantity() {
        return bookQuantity;
    }

    public void setBookQuantity(int bookQuantity) {
        this.bookQuantity = bookQuantity;
    }

    public double getBookPrice() {
        return bookPrice;
    }

    public void setBookPrice(double bookPrice) {
        this.bookPrice = bookPrice;
    }
}

2. 添加新的采购单

public void addPurchase() {
    // 获取采购单号等信息
    String purchaseID = "PUR" + System.currentTimeMillis();
    Date purchaseDate = new Date();
    String purchaser = "管理员";
    String supplier = "供应商A";
    String bookName = "Java编程思想";
    int bookQuantity = 10;
    double bookPrice = 68.8;

    // 将采购信息插入数据库
    Connection conn = null;
    PreparedStatement pstmt = null;
    try {
        conn = DBUtil.getConnection();
        String sql = "INSERT INTO purchase(purchase_id, purchase_date, purchaser, supplier, book_name, book_quantity, book_price) VALUES (?, ?, ?, ?, ?, ?, ?)";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, purchaseID);
        pstmt.setDate(2, new java.sql.Date(purchaseDate.getTime()));
        pstmt.setString(3, purchaser);
        pstmt.setString(4, supplier);
        pstmt.setString(5, bookName);
        pstmt.setInt(6, bookQuantity);
        pstmt.setDouble(7, bookPrice);
        int result = pstmt.executeUpdate();
        if (result > 0) {
            System.out.println("添加采购单成功！");
        } else {
            System.out.println("添加采购单失败！");
        }
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        DBUtil.close(conn, pstmt, null);
    }
}

3. 按月查看历史采购信息

public void viewPurchaseByMonth(int year, int month) {
    // 查询数据库中指定月份的采购信息
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
        conn = DBUtil.getConnection();
        String sql = "SELECT purchase_id, purchase_date, purchaser, supplier, book_name, book_quantity, book_price FROM purchase WHERE YEAR(purchase_date) = ? AND MONTH(purchase_date) = ?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, year);
        pstmt.setInt(2, month);
        rs = pstmt.executeQuery();
        while (rs.next()) {
            String purchaseID = rs.getString("purchase_id");
            Date purchaseDate = rs.getDate("purchase_date");
            String purchaser = rs.getString("purchaser");
            String supplier = rs.getString("supplier");
            String bookName = rs.getString("book_name");
            int bookQuantity = rs.getInt("book_quantity");
            double bookPrice = rs.getDouble("book_price");
            System.out.println(purchaseID + "\t" + purchaseDate + "\t" + purchaser + "\t" + supplier + "\t" + bookName + "\t" + bookQuantity + "\t" + bookPrice);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    } finally {
        DBUtil.close(conn, pstmt, rs);
    }
}

通过以上代码实现了图书进销存管理系统的采购管理功能，管理员可以添加新的采购单，并按月查看历史采购信息。