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java如何获取网页

2026-03-03 17:21:59Java

获取网页内容的方法

使用Java获取网页内容可以通过多种方式实现，以下是几种常见的方法：

使用`java.net.HttpURLConnection`

HttpURLConnection是Java标准库提供的HTTP客户端工具，适合简单的HTTP请求。

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

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

        int responseCode = connection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();
            System.out.println(response.toString());
        } else {
            System.out.println("GET request failed. Response Code: " + responseCode);
        }
    }
}

使用`java.net.http.HttpClient`（Java 11+）

Java 11引入了新的HttpClient，支持HTTP/2和异步请求。

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

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

使用第三方库（Apache HttpClient）

Apache HttpClient提供了更丰富的功能，适合复杂场景。

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class ApacheHttpClientExample {
    public static void main(String[] args) throws Exception {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpGet request = new HttpGet("https://example.com");

        CloseableHttpResponse response = client.execute(request);
        try {
            String result = EntityUtils.toString(response.getEntity());
            System.out.println(result);
        } finally {
            response.close();
        }
    }
}

使用Jsoup解析HTML

如果需要解析HTML内容，可以使用Jsoup库。

java如何获取网页

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

public class JsoupExample {
    public static void main(String[] args) throws Exception {
        Document doc = Jsoup.connect("https://example.com").get();
        String title = doc.title();
        System.out.println("Title: " + title);
    }
}