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Java网络编程入门：轻松掌握HTTP、Socket等关键技术，打造高效网络应用

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在数字化时代，网络编程是软件开发中不可或缺的一部分。Java作为一种跨平台、面向对象的编程语言，在网络编程领域有着广泛的应用。本文将带你入门Java网络编程，重点讲解HTTP、Socket等关键技术，帮助你打造高效的网络应用。

HTTP协议基础

HTTP（超文本传输协议）是互联网上应用最为广泛的网络协议之一。在Java中，我们可以使用java.net.HttpURLConnection类来发送HTTP请求。

发送GET请求

以下是一个简单的GET请求示例：

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

public class HttpGetExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://www.example.com");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            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());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

发送POST请求

与GET请求类似，发送POST请求也需要使用HttpURLConnection类。以下是一个发送POST请求的示例：

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpPostExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://www.example.com");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

            String urlParameters = "param1=value1&param2=value2";

            connection.setDoOutput(true);
            OutputStream os = connection.getOutputStream();
            DataOutputStream wr = new DataOutputStream(os);
            wr.writeBytes(urlParameters);
            wr.flush();
            wr.close();

            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());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Socket编程

Socket编程是Java网络编程的核心技术之一。它允许程序在网络中建立连接、发送和接收数据。

创建Socket连接

以下是一个简单的Socket客户端示例：

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

public class SocketClientExample {
    public static void main(String[] args) {
        try {
            Socket socket = new Socket("localhost", 1234);
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            out.println("Hello, server!");
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println("Server: " + inputLine);
            }

            out.close();
            in.close();
            socket.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

创建Socket服务器

以下是一个简单的Socket服务器示例：

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

public class SocketServerExample {
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(1234);
            System.out.println("Server is listening on port 1234");

            while (true) {
                Socket socket = serverSocket.accept();
                System.out.println("Client connected");

                BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

                String inputLine;
                while ((inputLine = in.readLine()) != null) {
                    System.out.println("Client: " + inputLine);
                    out.println("Server: " + inputLine);
                }

                in.close();
                out.close();
                socket.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

总结

本文介绍了Java网络编程入门，重点讲解了HTTP和Socket编程。通过学习这些关键技术，你可以轻松打造高效的网络应用。希望本文对你有所帮助！

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