API调用错误示例：Java如何正确使用HTTP客户端

原创 àì夳堔傛蜴生んèń 2024-10-14 06:51 103阅读 0赞

在Java中，我们可以使用各种HTTP客户端库来发送API请求。这里以`java.net.HttpURLConnection`和流行的Apache HttpClient库为例。

1. 使用HttpURLConnection：

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

public class HttpURLConnectionExample {
    public static void main(String[] args) throws Exception {
        // 创建URL对象
        URL url = new URL("https://api.example.com/endpoint");

// 使用HttpURLConnection发送GET请求
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        connection.setConnectTimeout(1000); // 设置连接超时

int responseCode = connection.getResponseCode();

if (responseCode == 200) { // 如果响应码为200（成功），则读取响应内容
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())));

String inputLine;
            StringBuffer content = new StringBuffer();

while ((inputLine = in.readLine()) != null) {
                content.append(inputLine);
            }

System.out.println("API Response Content: " + content.toString());
        } else {
            System.out.println("Failed to retrieve API data. Response Code: " + responseCode);
        }

connection.disconnect();
    }
}
```

2. 使用Apache HttpClient库：

```java
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.util.EntityUtils;

public class ApacheHttpClientExample {
    public static void main(String[] args) throws Exception {
        // 创建CloseableHttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

// 使用Apache HttpClient发送GET请求
        HttpGet httpGet = new HttpGet("https://api.example.com/endpoint");
        HttpResponse response = httpClient.execute(httpGet);

int responseCode = response.getStatusLine().getStatusCode();
        if (responseCode == 200) {
            String content = EntityUtils.toString(response.getEntity()));
            System.out.println("API Response Content: " + content);
        } else {
            System.out.println("Failed to retrieve API data. Response Code: " + responseCode));
        }

// 关闭HttpClient连接
        httpClient.close();
    }
}
```

请确保你已经添加了相应的依赖项。例如，如果你使用的是Apache HttpClient，你需要在项目的pom.xml文件中添加对应的依赖。