来一份数据服务器缓存加锁C++源码示例

以下是一个简单的数据服务器缓存加锁的C++源码示例：

#include <iostream>
#include <unordered_map>
#include <mutex>

class DataServerCache {
private:
    std::unordered_map<std::string, std::string> cache;
    std::mutex mutex;

public:
    std::string getData(const std::string& key) {
        std::lock_guard<std::mutex> lock(mutex);
        if (cache.find(key) != cache.end()) {
            return cache[key];
        }
        // Simulate fetching data from the actual data server
        std::string data = fetchDataFromServer(key);
        cache[key] = data;
        return data;
    }

    void updateData(const std::string& key, const std::string& data) {
        std::lock_guard<std::mutex> lock(mutex);
        cache[key] = data;
        // Simulate updating data on the actual data server
        updateDataOnServer(key, data);
    }

    void deleteData(const std::string& key) {
        std::lock_guard<std::mutex> lock(mutex);
        cache.erase(key);
        // Simulate deleting data from the actual data server
        deleteDataFromServer(key);
    }

private:
    std::string fetchDataFromServer(const std::string& key) {
        // Fetch data from the actual data server
        std::cout << "Fetching data from server for key: " << key << std::endl;
        // Simulating a delay in fetching data
        std::this_thread::sleep_for(std::chrono::seconds(2));
        return "Data for key: " + key;
    }

    void updateDataOnServer(const std::string& key, const std::string& data) {
        // Update data on the actual data server
        std::cout << "Updating data on server for key: " << key << std::endl;
        // Simulating a delay in updating data
        std::this_thread::sleep_for(std::chrono::seconds(2));
    }

    void deleteDataFromServer(const std::string& key) {
        // Delete data from the actual data server
        std::cout << "Deleting data from server for key: " << key << std::endl;
        // Simulating a delay in deleting data
        std::this_thread::sleep_for(std::chrono::seconds(2));
    }
};

int main() {
    DataServerCache cache;
    
    // Example usage
    std::string data = cache.getData("key1");
    std::cout << "Data: " << data << std::endl;

    cache.updateData("key2", "new data");
    std::cout << "Data updated." << std::endl;

    cache.deleteData("key1");
    std::cout << "Data deleted." << std::endl;

    return 0;
}

在这个示例中，DataServerCache类实现了一个简单的数据服务器缓存，并使用std::mutex来确保对缓存的并发访问是线程安全的。getData方法用于从缓存中获取数据，如果缓存中不存在，则从实际数据服务器获取数据，并将其存储在缓存中。updateData方法用于更新缓存和实际数据服务器中的数据。deleteData方法用于从缓存和实际数据服务器中删除数据