HTTP客户端开发：Java发送GET和POST请求的代码实例

原创迷南。 2024-10-21 21:21 25阅读 0赞

在Java中，我们可以使用Apache HttpClient或者OkHttp库来发送GET和POST请求。这里以这两个库为例，提供一个简单的代码实例：

**1. 使用Apache HttpClient**

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

public class ApacheClientExample {
    public static void main(String[] args) throws Exception {
        // 创建HTTP客户端
        CloseableHttpClient httpClient = HttpClients.createDefault();

// 发送GET请求
        HttpGet httpGet = new HttpGet("http://example.com");
        CloseableHttpResponse response = httpClient.execute(httpGet);
        if (response != null) {
            try {
                // 获取响应实体，通常用于获取HTTP状态码和响应内容
                HttpEntity entity = response.getEntity();
                int statusLineCode = response.getStatusLine().getStatusCode();
                System.out.println("Response Status Code: " + statusLineCode);
                if (entity != null && entity.getContentLength() > 0) {
                    // 如果有内容，将实体内容读取到字符串中
                    String content = EntityUtils.toString(entity);
                    System.out.println("Response Content: " + content);
                }
            } finally {
                // 关闭响应和客户端连接
                response.close();
                httpClient.close();
            }
        }
    }
}
```

**2. 使用OkHttp**

```java
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class OkHttpExample {
    public static void main(String[] args) throws Exception {
        // 创建OkHttpClient实例
        OkHttpClient client = new OkHttpClient();

// 发送GET请求
        Request request = new Request.Builder()
                .url("http://example.com") // 请求URL
                .build();
        Response response = client.newCall(request).execute();
        if (response != null) {
            try {
                // 获取响应实体，通常用于获取HTTP状态码和响应内容
                String content = response.body().string();
                int statusLineCode = response.status();
                System.out.println("Response Status Code: " + statusLineCode);
                System.out.println("Response Content: " + content);
            } finally {
                // 关闭响应
                response.close();
            }
        }
    }
}
```

这些示例代码中，GET请求的发送使用了`HttpGet`或`Request.Builder.get()`方法。POST请求的发送通常需要创建一个`Request.Builder.post()`方法构建的请求对象，并通过OkHttpClient或者HttpClient进行发送。