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如何java读网页

2026-03-23 00:12:34Java

使用 Java 读取网页内容

使用 `java.net.URL` 和 `java.io.BufferedReader`

通过 URL 类和 BufferedReader 可以快速读取网页内容。以下是示例代码：

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

public class ReadWebPage {
    public static void main(String[] args) throws Exception {
        URL url = new URL("https://example.com");
        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
    }
}

使用 `HttpURLConnection` 处理 HTTP 请求

HttpURLConnection 提供了更多控制选项，例如设置请求方法、超时和头部信息：

如何java读网页

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

public class ReadWebPageWithConnection {
    public static void main(String[] args) throws Exception {
        URL url = new URL("https://example.com");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setConnectTimeout(5000);
        conn.setReadTimeout(5000);

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
    }
}

使用第三方库（如 Apache HttpClient）

Apache HttpClient 提供了更高级的功能和更简洁的 API：

如何java读网页

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 ReadWebPageWithHttpClient {
    public static void main(String[] args) throws Exception {
        CloseableHttpClient client = HttpClients.createDefault();
        HttpGet request = new HttpGet("https://example.com");
        CloseableHttpResponse response = client.execute(request);
        String content = EntityUtils.toString(response.getEntity());
        System.out.println(content);
        response.close();
        client.close();
    }
}

使用 Jsoup 解析 HTML

如果需要解析 HTML 内容，可以使用 Jsoup 库：

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

public class ParseWebPageWithJsoup {
    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);
    }
}

处理异常和超时

在实际应用中，需要处理网络异常和超时：

try {
    URL url = new URL("https://example.com");
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setConnectTimeout(5000);
    conn.setReadTimeout(5000);
    // 其他操作
} catch (Exception e) {
    e.printStackTrace();
}