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java如何连网络

2026-03-26 08:56:51Java

Java 连接网络的方法

Java 提供了多种方式连接网络，主要依赖于 java.net 包中的类。以下是几种常见的实现方法。

使用 URL 和 URLConnection

URL 类用于表示统一资源定位符，URLConnection 用于建立与指定 URL 的连接。

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

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

使用 HttpURLConnection

HttpURLConnection 是 URLConnection 的子类，专门用于 HTTP 协议。

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

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

使用 Socket 编程

Socket 类用于建立客户端与服务器之间的连接。

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class SocketExample {
    public static void main(String[] args) throws Exception {
        Socket socket = new Socket("example.com", 80);
        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        out.println("GET / HTTP/1.1");
        out.println("Host: example.com");
        out.println();
        String line;
        while ((line = in.readLine()) != null) {
            System.out.println(line);
        }
        socket.close();
    }
}

使用第三方库（如 Apache HttpClient）

Apache HttpClient 是一个功能更丰富的 HTTP 客户端库。

java如何连网络

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

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet("https://example.com");
        HttpResponse response = client.execute(request);
        String result = EntityUtils.toString(response.getEntity());
        System.out.println(result);
    }
}