Java网络编程：HTTP请求响应问题剖析及实例

原创本是古典何须时尚 2024-11-26 01:15 6阅读 0赞

在Java中，我们可以使用各种库来处理HTTP请求和响应。这里我们主要看两种情况：使用Apache HttpClient库以及使用Java内置的URL和URLConnection。

1. 使用Apache HttpClient

```java
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.entity.StringEntity;

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        // 创建HTTP请求
        String url = "http://example.com/api/data";
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpEntity entity = new StringEntity("GET " + url);
        entity.setContentType("application/json");

// 执行HTTP请求并获取响应
        CloseableHttpResponse response = httpClient.execute(HttpRequestBuilder.newHttpRequestBuilder()
                .setURI(new URI(url)))
                .setMethod("GET")
                .build(), entity);

// 检查是否成功并处理响应数据
        if (response.getStatusLine().getStatusCode() == 200) {
            HttpEntity entityResponse = response.getEntity();
            String content = EntityUtils.toString(entityResponse);
            System.out.println(content); // 打印返回的数据
        }

// 关闭资源
        response.close();
        httpClient.close();
    }
}
```

2. 使用Java内置的URL和URLConnection

```java
import java.net.HttpURLConnection;
import java.net.URL;

public class URLConnectionExample {
    public static void main(String[] args) throws Exception {
        // 创建HTTP请求的URL
        String url = "http://example.com/api/data";
        URL obj = new URL(url);

// 使用URLConnection发送GET请求
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        con.setRequestMethod("GET");
        con.setRequestProperty("Accept", "application/json");

int responseCode = con.getResponseCode();

if (responseCode == 200) {
            byte[] content = new byte[(int) con.getContentLength()]];
            con.getInputStream().read(content);
            String result = new String(content, "UTF-8"));
            System.out.println(result); // 打印返回的数据
        }

// 关闭连接
        con.disconnect();
    }
}
```

这两种方式都可以用来发送HTTP GET请求，并接收响应数据。根据实际需求，可以选择适合的方式来实现Java的网络编程。