private String driver = "com.mysql.jdbc.Driver"; private String url = "jdbc:mysql://localhost:3306/rents?useUnicode=true&characterEncoding=utf-8"; private String user = "root"; private String password = "root"; public Connection getConnection() throws SQLException { try { Class.forName(driver); } catch (java.lang.ClassNotFoundException cnfe) { cnfe.printStackTrace(); } Connection conn = null; //conn=DriverManager.getConnection(URL, "root", "12481632"); try { conn = DriverManager.getConnection(url, user, password); }catch(SQLException ex) { ex.printStackTrace(); } return conn; } /*

这段代码是用Java编写的，用于建立与MySQL数据库的连接。其中，私有变量driver、url、user和password分别指定了MySQL数据库的驱动程序、连接URL、用户名和密码。getConnection()方法使用Java的JDBC API建立与MySQL数据库的连接，并返回一个Connection对象，该对象可用于执行SQL查询和更新等操作。在这个方法中，首先使用Class.forName()方法加载MySQL的JDBC驱动程序，然后使用DriverManager.getConnection()方法建立与MySQL数据库的连接。如果连接过程中出现异常，getConnection()方法将抛出SQLException异常并打印异常堆栈跟踪信息。

相关问题

A car rental company rents out a variety of cars and coaches and its rental rates are calculated on a daily basis. The relevant information of vehicle is shown in the following form. You need to develop a vehicle rental system according to the following requirements. (1) Design a simple console interactive interface to provide users with the related information about this vehicle rental system including vehicle models, specific information, daily rent and discount information so that the user can make further choices. (2) After understanding the relevant information, the user can input the relevant information of the vehicle which he or she wants to rent through the console program. (3) The program calculates the rent that the user needs to pay and informs the user through the console program. (4) You need to deal with the illegal information input by users through the console with some rules and prompt the corresponding error reason.For example, the user cannot input a negative value for the number of parking days.You need to consider as many misinput cases as possible. Please submit program code and the screenshot of the program output in the answer

I'm sorry, but as an AI language model, I am not able to submit program code or screenshots of program output. However, I can provide you with guidance on how to approach this problem.

To develop a vehicle rental system, you can use a programming language like Python and create a console-based interface using the built-in input and print functions. Here is a general outline of how you can implement the system:

1. Create a list of vehicle models with their specific information (e.g., brand, model, seating capacity, fuel type, etc.), daily rent, and discount information (e.g., 10% off for renting more than 7 days).

2. Display the list of vehicle models and their information to the user using the print function.

3. Prompt the user to input the model of the vehicle they want to rent, as well as the number of days they want to rent it for, using the input function.

4. Validate the input to ensure that the user has entered a valid model and a positive number of days. If the input is invalid, display an error message and prompt the user to input again.

5. Calculate the rent based on the daily rent and any applicable discounts, and display the total rent to the user using the print function.

6. End the program.

Here is some example code to get you started:

# Define the list of vehicle models and their information
vehicles = [
    {
        'model': 'Sedan',
        'info': 'Brand: Honda | Model: Civic | Seating Capacity: 5 | Fuel Type: Gasoline',
        'daily_rent': 50,
        'discount': 0.1
    },
    {
        'model': 'SUV',
        'info': 'Brand: Toyota | Model: RAV4 | Seating Capacity: 7 | Fuel Type: Gasoline',
        'daily_rent': 70,
        'discount': 0.15
    },
    {
        'model': 'Coach',
        'info': 'Brand: Mercedes | Model: Tourismo | Seating Capacity: 50 | Fuel Type: Diesel',
        'daily_rent': 300,
        'discount': 0.2
    }
]

# Display the list of vehicle models and their information
print('Available Vehicles:')
for vehicle in vehicles:
    print(vehicle['model'])
    print(vehicle['info'])
    print('Daily Rent:', vehicle['daily_rent'])
    print('Discount:', vehicle['discount'])
    print()

# Prompt the user to input the model and number of days
model = input('Enter the model of the vehicle you want to rent: ')
days = input('Enter the number of days you want to rent it for: ')

# Validate the input
valid_input = False
while not valid_input:
    try:
        days = int(days)
        if days <= 0:
            print('Error: Number of days must be positive')
        else:
            for vehicle in vehicles:
                if vehicle['model'] == model:
                    rent = vehicle['daily_rent'] * days * (1 - vehicle['discount'])
                    print('Total Rent:', rent)
                    valid_input = True
                    break
            else:
                print('Error: Invalid vehicle model')
                break
    except ValueError:
        print('Error: Number of days must be an integer')
        break

This is just a basic example, and you may need to customize it further to meet your specific requirements and handle more edge cases.

合同租金计算方法 需求：根据下面的条件生成每个月的月租金 递增周期：1年 租金递增率：6% 租赁开始时间 2021-03-01 租赁结束时间 2022-03-01 免租开始时间： 免租结束时间： 开始月租金：600 递增周期的时间是从租赁开始时间计算。(不是从免租结束时间计算) 说明租金计算逻辑。

根据需求，可以采用如下的租金计算逻辑：

1. 首先确定租赁周期，即租赁开始时间到租赁结束时间之间的月数。

2. 然后根据开始月租金和递增周期，计算出每个递增周期结束时的月租金。具体计算方法为：每个递增周期结束时的月租金 = 上一个递增周期结束时的月租金 * (1 + 租金递增率)。

3. 接着按照每个递增周期结束时的月租金，依次计算出每个月的月租金。具体计算方法为：每个月的月租金 = 每个递增周期结束时的月租金 * (租赁周期中经过的月数 / 递增周期的月数)。

4. 如果有免租期，则需要在计算出来的月租金中减去免租期内的月租金。

具体实现时，可以按照以下步骤进行：

1. 使用 Python 中的 datetime 模块计算租赁周期中经过的月数。

from datetime import datetime

start_date = datetime.strptime('2021-03-01', '%Y-%m-%d')
end_date = datetime.strptime('2022-03-01', '%Y-%m-%d')
lease_months = (end_date.year - start_date.year) * 12 + (end_date.month - start_date.month)

2. 计算每个递增周期结束时的月租金。

base_rent = 600  # 开始月租金
increment_rate = 0.06  # 租金递增率
increment_period = 12  # 递增周期

rents = [base_rent]
for i in range(increment_period, lease_months + increment_period, increment_period):
    next_rent = rents[-1] * (1 + increment_rate)
    rents.append(next_rent)

3. 计算每个月的月租金。

monthly_rents = []
for i in range(lease_months):
    rent = rents[i // increment_period] * (i % increment_period + 1) / increment_period
    monthly_rents.append(rent)

4. 如果有免租期，则需要在计算出来的月租金中减去免租期内的月租金。

free_start_date = datetime.strptime('2021-04-01', '%Y-%m-%d')  # 免租开始时间
free_end_date = datetime.strptime('2021-06-30', '%Y-%m-%d')  # 免租结束时间

for i in range(lease_months):
    rent_date = start_date.replace(day=1) + timedelta(days=i * 30)
    if free_start_date <= rent_date <= free_end_date:
        monthly_rents[i] = 0

最终得到的 monthly_rents 列表中存储了每个月的月租金。