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java 如何获取cookie

2026-04-09 07:12:18Java

获取 Cookie 的方法

在 Java 中获取 Cookie 通常涉及 HTTP 请求和响应的处理。以下是几种常见的方法：

使用 HttpURLConnection

通过 HttpURLConnection 发送 HTTP 请求并获取响应中的 Cookie：

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
import java.util.Map;

public class CookieExample {
    public static void main(String[] args) throws Exception {
        URL url = new URL("https://example.com");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

        // 发送请求
        connection.setRequestMethod("GET");
        connection.connect();

        // 获取响应头中的 Cookie
        Map<String, List<String>> headers = connection.getHeaderFields();
        List<String> cookies = headers.get("Set-Cookie");

        if (cookies != null) {
            for (String cookie : cookies) {
                System.out.println("Cookie: " + cookie);
            }
        }
    }
}

使用 HttpClient（Java 11+）

Java 11 引入了新的 HttpClient，可以更方便地处理 HTTP 请求和 Cookie：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.Optional;

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://example.com"))
                .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

        // 获取响应头中的 Cookie
        Optional<String> cookie = response.headers().firstValue("Set-Cookie");
        cookie.ifPresent(c -> System.out.println("Cookie: " + c));
    }
}

使用第三方库（如 Apache HttpClient）

Apache HttpClient 是一个功能强大的 HTTP 客户端库，可以更灵活地处理 Cookie：

import org.apache.http.client.CookieStore;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

public class ApacheHttpClientExample {
    public static void main(String[] args) throws Exception {
        CookieStore cookieStore = new BasicCookieStore();
        CloseableHttpClient client = HttpClients.custom()
                .setDefaultCookieStore(cookieStore)
                .build();

        HttpGet request = new HttpGet("https://example.com");
        CloseableHttpResponse response = client.execute(request);

        // 获取 CookieStore 中的 Cookie
        cookieStore.getCookies().forEach(cookie -> {
            System.out.println("Cookie: " + cookie.getName() + "=" + cookie.getValue());
        });

        response.close();
        client.close();
    }
}

从 Servlet 中获取 Cookie

在 Java Web 应用中，可以通过 HttpServletRequest 获取客户端发送的 Cookie：

java 如何获取cookie

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CookieServlet extends HttpServlet {
    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
        Cookie[] cookies = request.getCookies();
        if (cookies != null) {
            for (Cookie cookie : cookies) {
                System.out.println("Cookie: " + cookie.getName() + "=" + cookie.getValue());
            }
        }
    }
}