httpclient 上传文件

你可以使用 HttpClient 来上传文件。下面是一个使用 HttpClient 上传文件的示例代码：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.HttpClientBuilder;

import java.io.File;
import java.io.IOException;

public class FileUploader {
    public static void main(String[] args) {
        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost httpPost = new HttpPost("http://example.com/upload");

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);

        // 添加文件参数
        File file = new File("path/to/file.txt");
        builder.addBinaryBody("file", file, ContentType.DEFAULT_BINARY, file.getName());

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

        try {
            HttpResponse response = httpClient.execute(httpPost);
            // 处理上传结果
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

你需要将 `http://example.com/upload` 替换为你要上传文件的目标 URL，将 `"path/to/file.txt"` 替换为你要上传的文件路径。在这个示例中，我们使用了 HttpClient 4.x 版本的库进行文件上传。