java实现httpclient请求，并且请求中会传输MP4文件，也会传递其他参数，要求设置头部Content-Type: application/mp4

可以使用Apache HttpClient库来实现HTTP请求，以下是一个示例代码：

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

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.EntityBuilder;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.message.BasicNameValuePair;

public class HttpClientExample {
    public static void main(String[] args) throws ClientProtocolException, IOException {
        String url = "http://example.com/upload"; // 上传接口地址
        String filePath = "/path/to/file.mp4"; // MP4文件路径

        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);

        // 设置请求头部
        httpPost.setHeader("Content-Type", "application/mp4");

        // 设置请求参数
        List<NameValuePair> params = new ArrayList<>();
        params.add(new BasicNameValuePair("name", "value"));
        httpPost.setEntity(new UrlEncodedFormEntity(params));

        // 设置上传文件
        File file = new File(filePath);
        InputStream inputStream = new FileInputStream(file);
        HttpEntity fileEntity = EntityBuilder.create()
                .setContentType(ContentType.APPLICATION_OCTET_STREAM)
                .setBinary(inputStream)
                .build();

        // 组装请求实体，包括文件和参数
        HttpEntity reqEntity = MultipartEntityBuilder.create()
                .addBinaryBody("file", fileEntity, ContentType.APPLICATION_OCTET_STREAM, file.getName())
                .addTextBody("name", "value")
                .build();

        httpPost.setEntity(reqEntity);

        // 执行请求
        HttpResponse httpResponse = client.execute(httpPost);
        HttpEntity responseEntity = httpResponse.getEntity();

        // 处理响应数据
        System.out.println(responseEntity.getContent());
    }
}

在这个示例中，我们使用`HttpPost`实例来构建一个POST请求，设置了请求头部`Content-Type: application/mp4`，并添加了一个MP4文件和其他参数到请求实体中。在执行请求后，我们可以从响应实体中获取响应数据。需要注意的是，这里使用了MultipartEntityBuilder来组装请求实体，因为请求中包含了文件和其他参数，而Multipart实体可以同时包含多个不同类型的HTTP实体。