在Java中进行网络编程：HTTP请求、Socket通信案例

原创水深无声 2024-11-23 05:39 21阅读 0赞

在网络编程中，Java通常通过Java内置的HttpURLConnection或者第三方库如Spring Boot的RestTemplate来处理HTTP请求。

下面是一个使用HttpURLConnection发送GET请求的例子：

```java
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) {
        String urlStr = "http://example.com"; // 替换为你要访问的URL

try {
            URL url = new URL(urlStr);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

// 设置请求方式
            httpURLConnection.setRequestMethod("GET");

// 如果需要的话，可以设置超时时间
            int timeoutSeconds = 10;
            httpURLConnection.setConnectTimeout(timeoutSeconds);
            httpURLConnection.setReadTimeout(timeoutSeconds);

// 获取响应码
            int responseCode = httpURLConnection.getResponseCode();

System.out.println("Response Code: " + responseCode);

// 如果请求成功，读取响应内容
            if (responseCode == 200) {
                BufferedReader br = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream())));

StringBuilder sb = new StringBuilder();
                String line;
                while ((line = br.readLine()) != null) {
                    sb.append(line).append("\n");
                }

System.out.println("Response Content: " + sb.toString());

} else if (responseCode >= 400 && responseCode < 500) {
                // 请求状态错误，如404或500
                System.err.println("Error Response Code: " + responseCode);
            }

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

对于Socket通信，通常会创建ServerSocket监听连接，然后建立Socket与客户端进行双向通信。

以下是一个简单的Socket服务器和客户端的例子：

```java
// 服务器端
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    private static final int PORT = 1234; // 设置端口

public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(PORT);

System.out.println("Server started on port: " + PORT);

while (true) {
            Socket clientSocket = serverSocket.accept();

System.out.println("New connection established from: " + clientSocket.getRemoteSocketAddress()));

// 与客户端进行通信
            handleClient(clientSocket);
        }
    }

private static void handleClient(Socket clientSocket) throws IOException {
        BufferedReader inFromClient = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())));

String inputLine;
        while ((inputLine = inFromClient.readLine()) != null)) {
            System.out.println("Received from client: " + inputLine));

// 你可以在这里处理客户端的输入
            handleInput(inputLine);
        }

inFromClient.close();
        clientSocket.close();
    }

private static void handleInput(String inputLine) {
        // 这里只是一个示例，你可以根据实际需求进行处理
        System.out.println("Processing received input: " + inputLine));

// 假设你想要将输入字符串转换为整数并打印
        int integerValue = Integer.parseInt(inputLine);
        System.out.println("Integer value from input: " + integerValue);
    }
}
```

这两个例子展示了Java进行网络编程的基本步骤。