用java和MySQL实现访客管理系统的黑名单的增删改查功能的代码，并且这个代码里包含了异常处理。

以下是一个简单的访客管理系统的黑名单增删改查功能的Java代码，使用MySQL作为数据库，并包含异常处理：

import java.sql.*;
import java.util.Scanner;

public class BlacklistManagementSystem {
    // 定义数据库连接信息
    private static final String DRIVER = "com.mysql.jdbc.Driver";
    private static final String URL = "jdbc:mysql://localhost:3306/guestbook";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "password";

    // 定义常量表示SQL语句
    private static final String INSERT_SQL = "INSERT INTO blacklist(name, reason) VALUES (?, ?)";
    private static final String DELETE_SQL = "DELETE FROM blacklist WHERE id = ?";
    private static final String UPDATE_SQL = "UPDATE blacklist SET name = ?, reason = ? WHERE id = ?";
    private static final String SELECT_SQL = "SELECT * FROM blacklist WHERE id = ?";

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("请选择操作：1.添加黑名单 2.删除黑名单 3.修改黑名单 4.查询黑名单 5.退出");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addBlacklist();
                    break;
                case 2:
                    deleteBlacklist();
                    break;
                case 3:
                    updateBlacklist();
                    break;
                case 4:
                    selectBlacklist();
                    break;
                case 5:
                    System.out.println("再见！");
                    return;
                default:
                    System.out.println("无效的操作！");
                    break;
            }
        }
    }

    // 添加黑名单
    private static void addBlacklist() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入姓名：");
        String name = scanner.nextLine();
        System.out.println("请输入原因：");
        String reason = scanner.nextLine();

        try (Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
             PreparedStatement stmt = conn.prepareStatement(INSERT_SQL)) {
            stmt.setString(1, name);
            stmt.setString(2, reason);
            int count = stmt.executeUpdate();
            if (count > 0) {
                System.out.println("添加成功！");
            } else {
                System.out.println("添加失败！");
            }
        } catch (SQLException e) {
            System.out.println("添加失败：" + e.getMessage());
        }
    }

    // 删除黑名单
    private static void deleteBlacklist() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要删除的黑名单id：");
        int id = scanner.nextInt();
        scanner.nextLine(); // 读取多余的换行符

        try (Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
             PreparedStatement stmt = conn.prepareStatement(DELETE_SQL)) {
            stmt.setInt(1, id);
            int count = stmt.executeUpdate();
            if (count > 0) {
                System.out.println("删除成功！");
            } else {
                System.out.println("删除失败！");
            }
        } catch (SQLException e) {
            System.out.println("删除失败：" + e.getMessage());
        }
    }

    // 修改黑名单
    private static void updateBlacklist() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要修改的黑名单id：");
        int id = scanner.nextInt();
        scanner.nextLine(); // 读取多余的换行符
        System.out.println("请输入姓名：");
        String name = scanner.nextLine();
        System.out.println("请输入原因：");
        String reason = scanner.nextLine();

        try (Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
             PreparedStatement stmt = conn.prepareStatement(UPDATE_SQL)) {
            stmt.setString(1, name);
            stmt.setString(2, reason);
            stmt.setInt(3, id);
            int count = stmt.executeUpdate();
            if (count > 0) {
                System.out.println("修改成功！");
            } else {
                System.out.println("修改失败！");
            }
        } catch (SQLException e) {
            System.out.println("修改失败：" + e.getMessage());
        }
    }

    // 查询黑名单
    private static void selectBlacklist() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要查询的黑名单id：");
        int id = scanner.nextInt();
        scanner.nextLine(); // 读取多余的换行符

        try (Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
             PreparedStatement stmt = conn.prepareStatement(SELECT_SQL)) {
            stmt.setInt(1, id);
            ResultSet rs = stmt.executeQuery();
            if (rs.next()) {
                System.out.println("姓名：" + rs.getString("name"));
                System.out.println("原因：" + rs.getString("reason"));
            } else {
                System.out.println("未找到该黑名单！");
            }
        } catch (SQLException e) {
            System.out.println("查询失败：" + e.getMessage());
        }
    }
}

这个代码使用了Java的JDBC API来连接MySQL数据库，并使用了PreparedStatement来执行带参数的SQL语句，以避免SQL注入攻击。在每个操作中都包含了异常处理代码，以避免程序崩溃并能够给用户友好的提示信息。