java使用org.apache.http.client.HttpClient上传文件

以下是一个使用org.apache.http.client.HttpClient上传文件的Java示例：

import java.io.File;
import java.io.IOException;
import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

public class FileUploader {

    public static void main(String[] args) {
        String url = "http://example.com/upload";
        String filePath = "/path/to/file.jpg";

        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httpPost = new HttpPost(url);

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addBinaryBody("file", new File(filePath));

        HttpEntity multipart = builder.build();
        httpPost.setEntity(multipart);

        try {
            httpClient.execute(httpPost);
            HttpEntity responseEntity = httpResponse.getEntity();
            String responseString = EntityUtils.toString(responseEntity, "UTF-8");
            System.out.println(responseString);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

在此示例中，我们使用HttpClient创建一个HttpPost请求对象，并使用MultipartEntityBuilder创建一个multipart/form-data实体，以便我们可以将文件作为二进制数据添加到请求中。最后，我们使用execute方法将请求发送到服务器，并从响应中提取响应字符串。