java httppost上传文件

好的，以下是Java使用HttpPost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.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class HttpPostUploadFileExample {

    public static void main(String[] args) {

        HttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost("http://example.com/upload");

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addPart("file", new FileBody(new File("/path/to/file")));

        httpPost.setEntity(builder.build());

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

    }

}

其中，`http://example.com/upload` 是上传文件的接口地址，`/path/to/file` 是要上传的文件路径。在这个示例中，使用了 Apache HttpClient 和 Apache HttpCore 库，需要导入相应的依赖。