AWS环境变量的替代方法是使用AWS SDK提供的配置文件或凭证文件来存储和管理AWS凭证信息。以下是一个使用AWS SDK的Python代码示例：

import boto3
from botocore.exceptions import NoCredentialsError

# 创建一个AWS配置文件
def create_aws_config_file(access_key, secret_key, region):
    config = f"[default]\naws_access_key_id = {access_key}\naws_secret_access_key = {secret_key}\nregion = {region}\n"
    with open("~/.aws/credentials", "w") as file:
        file.write(config)

# 使用配置文件来读取AWS凭证信息
def read_aws_credentials_from_config_file():
    session = boto3.Session(profile_name="default")
    credentials = session.get_credentials()
    aws_access_key_id = credentials.access_key
    aws_secret_access_key = credentials.secret_key
    aws_session_token = credentials.token
    return aws_access_key_id, aws_secret_access_key, aws_session_token

# 使用凭证文件来读取AWS凭证信息
def read_aws_credentials_from_credentials_file():
    session = boto3.Session()
    credentials = session.get_credentials()
    aws_access_key_id = credentials.access_key
    aws_secret_access_key = credentials.secret_key
    aws_session_token = credentials.token
    return aws_access_key_id, aws_secret_access_key, aws_session_token

# 使用AWS SDK调用AWS服务的示例
def example_aws_sdk_usage():
    try:
        s3 = boto3.client('s3')
        response = s3.list_buckets()
        print(response)
    except NoCredentialsError:
        print("AWS凭证未配置或配置错误")

# 使用配置文件进行AWS SDK的初始化
def initialize_sdk_with_config_file():
    session = boto3.Session(profile_name="default")
    s3 = session.client('s3')
    return s3

# 使用凭证文件进行AWS SDK的初始化
def initialize_sdk_with_credentials_file():
    session = boto3.Session()
    s3 = session.client('s3')
    return s3

# 创建AWS配置文件
create_aws_config_file("YOUR_ACCESS_KEY", "YOUR_SECRET_KEY", "us-west-2")

# 使用配置文件读取AWS凭证信息
access_key, secret_key, session_token = read_aws_credentials_from_config_file()
print(f"AWS Access Key ID: {access_key}")
print(f"AWS Secret Access Key: {secret_key}")
print(f"AWS Session Token: {session_token}")

# 使用凭证文件读取AWS凭证信息
access_key, secret_key, session_token = read_aws_credentials_from_credentials_file()
print(f"AWS Access Key ID: {access_key}")
print(f"AWS Secret Access Key: {secret_key}")
print(f"AWS Session Token: {session_token}")

# 使用AWS SDK调用AWS服务的示例
example_aws_sdk_usage()

# 使用配置文件进行AWS SDK的初始化
s3_client = initialize_sdk_with_config_file()
print(s3_client.list_buckets())

# 使用凭证文件进行AWS SDK的初始化
s3_client = initialize_sdk_with_credentials_file()
print(s3_client.list_buckets())

上述代码中，首先使用create_aws_config_file函数创建一个AWS配置文件（credentials），将AWS访问密钥、密钥和区域信息写入文件。然后，read_aws_credentials_from_config_file和read_aws_credentials_from_credentials_file函数分别使用配置文件和凭证文件来读取AWS凭证信息。example_aws_sdk_usage函数展示了使用AWS SDK调用AWS服务的示例，如果凭证未配置或配置错误，会捕获NoCredentialsError并打印错误信息。initialize_sdk_with_config_file和initialize_sdk_with_credentials_file函数分别使用配置文件和凭证文件来初始化AWS SDK，返回一个AWS服务的客户端对象，可以使用该对象调用AWS服务的方法。

请确保安装并正确配置AWS SDK并替换示例代码中的访问密钥、密钥和区域信息。