最近在對接某第三方視訊服務商的介面，使用java在後臺呼叫他們的介面。在對接設定封面時遇到一個問題，他們需要對個引數，且有一個引數的型別為file。苦尋半天，果。遂記錄如下。

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @author Administrator
 *
 */
public
 
 class WeihouUtil {
    public static void main(String[] args){
        setActiveImage("1", "v10624388", "xinchengzhihuics", "451976930", "C:\\Users\\Administrator\\Desktop\\1_yuruixin_china.jpg");
    }

    /**
     * @param auth_type
     * @param account
     * @param password
     * @param webinar_id
     * @param
 
 image
     * @return
     */
    public static String setActiveImage(String auth_type,String account,String password,String webinar_id,String image ){
        String resStr = null;
        try{
            String boundary = "Boundary-b1ed-4060-99b9-fca7ff59c113"; //Could be any string
            String Enter = "\r\n"
 
;

            File file = new File(image);
            FileInputStream fis = new FileInputStream(file);

            URL url = new URL("http://e.vhall.com/api/vhallapi/v2/webinar/activeimage");
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestMethod("POST");
            conn.setUseCaches(false);
            conn.setInstanceFollowRedirects(true);
            conn.setRequestProperty("Content-Type","multipart/form-data;boundary=" + boundary); 

            conn.connect();

            DataOutputStream dos = new DataOutputStream(conn.getOutputStream());

          //part 1
            String part1 =  "--" + boundary + Enter
                    + "Content-Type: application/octet-stream" + Enter
                    + "Content-Disposition: form-data; filename=\""+file.getName()+"\"; name=\"image\"" + Enter + Enter;
          //part 2
            String part2 = Enter
                    + "--" + boundary + Enter
                    + "Content-Type: text/plain" + Enter
                    + "Content-Disposition: form-data; name=\"webinar_id\"" + Enter + Enter
                    + webinar_id + Enter
                    + "--" + boundary + "--";
            //part 3
            String part3 = Enter
                    + "--" + boundary + Enter
                    + "Content-Type: text/plain" + Enter
                    + "Content-Disposition: form-data; name=\"auth_type\"" + Enter + Enter
                    + auth_type + Enter
                    + "--" + boundary + "--";
            //part 4
            String part4 = Enter
                    + "--" + boundary + Enter
                    + "Content-Type: text/plain" + Enter
                    + "Content-Disposition: form-data; name=\"account\"" + Enter + Enter
                    + account + Enter
                    + "--" + boundary + "--";
            //part 5
            String part5 = Enter
                    + "--" + boundary + Enter
                    + "Content-Type: text/plain" + Enter
                    + "Content-Disposition: form-data; name=\"password\"" + Enter + Enter
                    + password + Enter
                    + "--" + boundary + "--";

            byte[] xmlBytes = new byte[fis.available()];
            fis.read(xmlBytes);

            dos.writeBytes(part1);
            dos.write(xmlBytes);
            dos.writeBytes(part2);
            dos.writeBytes(part3);
            dos.writeBytes(part4);
            dos.writeBytes(part5);

            dos.flush();
            dos.close();
            fis.close();

            System.out.println("status code: "+conn.getResponseCode());
            InputStream in = conn.getInputStream();
            int ch;
            StringBuilder sb2 = new StringBuilder();
            while ((ch = in.read()) != -1)
            {
                sb2.append((char) ch);
            }
            resStr = sb2.toString();
            System.out.println(resStr);
            conn.disconnect();

        }catch(Exception e){
            e.printStackTrace();
        }
        return resStr;
    }
}