在Java中，可以使用java.net.HttpURLConnection或者第三方庫Apache HttpClient來模擬Cookie操作。這里我將分別介紹這兩種方法。

方法1：使用java.net.HttpURLConnection

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class CookieExample {
    public static void main(String[] args) throws Exception {
        String url = "https://example.com";
        String cookie = "key=value";

        URL obj = new URL(url);
        HttpURLConnection connection = (HttpURLConnection) obj.openConnection();

        // 設置Cookie
        connection.setRequestProperty("Cookie", cookie);

        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);

        BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        System.out.println(response.toString());
    }
}

方法2：使用Apache HttpClient

首先，需要添加Apache HttpClient的依賴。如果你使用Maven，可以在pom.xml文件中添加以下依賴：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

然后，可以使用以下代碼模擬Cookie操作：

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class CookieExample {
    public static void main(String[] args) {
        String url = "https://example.com";
        String cookie = "key=value";

        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet(url);

        // 設置Cookie
        httpGet.setHeader("Cookie", cookie);

        try {
            HttpResponse response = httpClient.execute(httpGet);
            String result = EntityUtils.toString(response.getEntity());
            System.out.println(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

這兩種方法都可以用來模擬Cookie操作。使用哪種方法取決于你的需求和項目結構。