如何在android Volley Multi-part中将空文件与其他头部一起发送

import com.android.volley.AuthFailureError;
import com.android.volley.NetworkResponse;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyLog;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class MultiPartRequest extends Request<String> {
    private final String boundary = "*****";
    private final String lineEnd = "\r\n";
    private final String twoHyphens = "--";

    private Map<String, String> headers;
    private Map<String, File> files;

    public MultiPartRequest(int method, String url, Map<String, String> headers, Map<String, File> files,
                            Response.Listener<String> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.headers = headers;
        this.files = files;
        setShouldCache(false);
    }

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        return headers != null ? headers : super.getHeaders();
    }

    @Override
    public String getBodyContentType() {
        return "multipart/form-data;boundary=" + boundary;
    }

    @Override
    public byte[] getBody() throws AuthFailureError {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            if (files != null && !files.isEmpty()) {
                for (Map.Entry<String, File> entry : files.entrySet()) {
                    String fieldName = entry.getKey();
                    File file = entry.getValue();

                    bos.write((twoHyphens + boundary + lineEnd).getBytes());
                    bos.write(("Content-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"" + file.getName() + "\"" + lineEnd).getBytes());
                    bos.write(("Content-Type: " + getMimeType(file.getAbsolutePath()) + lineEnd).getBytes());
                    bos.write(lineEnd.getBytes());

                    // Read the file's bytes and write them to the output stream
                    byte[] fileBytes = FileUtils.readFileToByteArray(file);
                    bos.write(fileBytes);
                    bos.write(lineEnd.getBytes());
                }
            }

            bos.write((twoHyphens + boundary + twoHyphens + lineEnd).getBytes());
            return bos.toByteArray();
        } catch (IOException e) {
            VolleyLog.e("IOException writing to ByteArrayOutputStream");
            return null;
        } finally {
            try {
                bos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private String getMimeType(String filePath) {
        // Implement your logic to get the MIME type of the file based on its extension
        return "image/jpeg";
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse response) {
        // Implement your logic to parse the network response
        return null;
    }

    @Override
    protected void deliverResponse(String response) {
        // Implement your logic to deliver the response
    }
}

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.Volley;

import java.io.File;
import java.util.HashMap;
import java.util.Map;

public class MainActivity extends AppCompatActivity {
    private RequestQueue requestQueue;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        requestQueue = Volley.newRequestQueue(this);

        // 设置其他请求头部信息
        Map<String, String> headers = new HashMap<>();
        headers.put("Authorization", "Bearer your_token");

        // 设置要上传的文件
        Map<String, File> files = new HashMap<>();
        files.put("file", new File("path_to_your_file"));

        // 创建自定义的MultiPartRequest对象
        MultiPartRequest multiPartRequest = new MultiPartRequest(Request.Method.POST, "your_url",
                headers, files, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                // 处理请求成功的响应
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                // 处理请求失败的响应
            }
        });

        // 将请求添加到请求队列中
        requestQueue.add(multiPartRequest);
    }
}