httpclient 文件上传工具类

以下是一个示例的 HttpClient 文件上传工具类，可以帮助你上传文件：

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

import org.apache.commons.io.FileUtils;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpClientFileUploader {
    
    public static void uploadFile(String url, File file) throws IOException {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addBinaryBody("file", file, ContentType.MULTIPART_FORM_DATA, file.getName());
        HttpEntity multipart = builder.build();
        
        httpPost.setEntity(multipart);
        
        CloseableHttpResponse response = httpClient.execute(httpPost);
        try {
            HttpEntity responseEntity = response.getEntity();
            if (responseEntity != null) {
                String responseString = EntityUtils.toString(responseEntity, StandardCharsets.UTF_8);
                System.out.println(responseString);
            }
        } finally {
            response.close();
        }
    }

    public static void main(String[] args) throws IOException {
        File file = new File("path/to/file.txt");
        String url = "http://example.com/upload";
        uploadFile(url, file);
    }

}

此示例使用 Apache HttpClient 库。请确保将其添加到项目依赖项中。