要实现"AAD服务到具有证书JWT的服务"，可以使用以下代码示例来解决问题：

首先，创建一个包含AAD服务的代码示例：

import requests

# AAD服务配置
tenant_id = "your_tenant_id"
client_id = "your_client_id"
client_secret = "your_client_secret"
resource = "https://your_resource_url"

# 获取AAD访问令牌
def get_aad_token():
    url = f"https://login.microsoftonline.com/{tenant_id}/oauth2/token"
    data = {
        "grant_type": "client_credentials",
        "client_id": client_id,
        "client_secret": client_secret,
        "resource": resource
    }
    response = requests.post(url, data=data)
    response_json = response.json()
    if "access_token" in response_json:
        return response_json["access_token"]
    else:
        raise Exception("Failed to get AAD token")

# 使用AAD访问令牌调用API
def call_api_with_aad_token(aad_token):
    headers = {
        "Authorization": f"Bearer {aad_token}"
    }
    response = requests.get("https://your_api_url", headers=headers)
    return response.json()

# 获取AAD访问令牌并调用API
aad_token = get_aad_token()
response_data = call_api_with_aad_token(aad_token)
print(response_data)

然后，创建一个包含证书JWT的服务的代码示例：

import requests
import jwt
from datetime import datetime, timedelta

# 证书配置
private_key = open("private_key.pem").read()
public_key = open("public_key.pem").read()

# 生成JWT
def generate_jwt():
    now = datetime.utcnow()
    payload = {
        "iss": "your_issuer",
        "sub": "your_subject",
        "aud": "your_audience",
        "exp": now + timedelta(minutes=30),
        "nbf": now,
        "iat": now
    }
    return jwt.encode(payload, private_key, algorithm="RS256")

# 使用JWT调用API
def call_api_with_jwt(jwt_token):
    headers = {
        "Authorization": f"Bearer {jwt_token}"
    }
    response = requests.get("https://your_api_url", headers=headers)
    return response.json()

# 生成JWT并调用API
jwt_token = generate_jwt()
response_data = call_api_with_jwt(jwt_token)
print(response_data)

最后，将两个示例结合起来，即可实现"AAD服务到具有证书JWT的服务"的功能：

import requests
import jwt
from datetime import datetime, timedelta

# AAD服务配置
aad_tenant_id = "your_aad_tenant_id"
aad_client_id = "your_aad_client_id"
aad_client_secret = "your_aad_client_secret"
aad_resource = "https://your_aad_resource_url"

# 证书配置
private_key = open("private_key.pem").read()
public_key = open("public_key.pem").read()

# 获取AAD访问令牌
def get_aad_token():
    url = f"https://login.microsoftonline.com/{aad_tenant_id}/oauth2/token"
    data = {
        "grant_type": "client_credentials",
        "client_id": aad_client_id,
        "client_secret": aad_client_secret,
        "resource": aad_resource
    }
    response = requests.post(url, data=data)
    response_json = response.json()
    if "access_token" in response_json:
        return response_json["access_token"]
    else:
        raise Exception("Failed to get AAD token")

# 生成JWT
def generate_jwt():
    now = datetime.utcnow()
    payload = {
        "iss": "your_issuer",
        "sub": "your_subject",
        "aud": "your_audience",
        "exp": now + timedelta(minutes=30),
        "nbf": now,
        "iat": now
    }
    return jwt.encode(payload, private_key, algorithm="RS256")

# 使用AAD访问令牌调用API
def call_api_with_aad_token(aad_token):
    headers = {
        "Authorization": f"Bearer {aad_token}"
    }
    response = requests.get("https://your_api_url", headers=headers)
    return response.json()

# 使用JWT调用API
def call_api_with_jwt(jwt_token):
    headers = {
        "Authorization": f"Bearer {jwt_token}"
    }
    response = requests.get("https://your_api_url", headers=headers)