java之微信开发回复图片消息

微信开发文档见：详见
具体实现见：详见

public class WxController {

    public static final Logger LOGGER= LoggerFactory.getLogger(WxController.class);

    //type传image
    public static String upload(String accessToken,String filePath,String type) throws IOException {

        //判断文件是否存在
        File file=new File(filePath);
        if (!file.exists() || !file.isFile()){
            throw new IOException("文件不存在");
        }

        //新建请求url
        String url="https://api.weixin.qq.com/cgi-bin/media/upload?access_token="+accessToken+"&type="+type;

        URL u=new URL(url);
        HttpURLConnection connection= (HttpURLConnection) u.openConnection();

        connection.setRequestMethod("POST");
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setUseCaches(false);

        //设置头信息

        connection.setRequestProperty("Connection","Keep-Alive");
        connection.setRequestProperty("Charset","UTF-8");

        //设置边界

        String bound="-------"+ System.currentTimeMillis();

        connection.setRequestProperty("Content-Type","multipart/form-data; boundary="+bound);

        StringBuilder stringBuilder=new StringBuilder();

        stringBuilder.append("--").append(bound).append("\r\n").
                append("Content-Disposition:form-data;name=\"file\";filename=\""+file.getName()+"\"\r\n").
                append("Content-Type:application/octet-stream\r\n\r\n");
        byte[] head=stringBuilder.toString().getBytes("utf-8");

        //获得输出流

        OutputStream outputStream=new DataOutputStream(connection.getOutputStream());
        outputStream.write(head);

        //文件正文
        DataInputStream in=new DataInputStream(new FileInputStream(file));
        int bytes=0;
        byte[] buffer=new byte[1024];
        while((bytes=in.read(buffer))!=-1){
            outputStream.write(buffer,0,bytes);
        }
        in.close();

        //文件结尾
        byte[] foot=("\r\n--"+bound+"--\r\n").getBytes("utf-8");
        outputStream.write(foot);
        outputStream.flush();
        outputStream.close();

        StringBuffer stringBuffer=new StringBuffer();
        BufferedReader bufferedReader=null;
        String result=null;
        try {
            //获取url响应
            bufferedReader=new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line=null;
            while ((line=bufferedReader.readLine())!=null){
                    stringBuffer.append(line);
            }
            if (result==null){
                result=stringBuffer.toString();
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            if (bufferedReader!=null){
                bufferedReader.close();
            }
        }

        //转化结果
        JSONObject jsonObject= JSON.parseObject(result);
        LOGGER.info(jsonObject.toJSONString());

        String typeName="media_id";
        if (!"image".equals(type)){
            typeName=type+"_media_id";
        }
        String media_id= (String) jsonObject.get(typeName);
        LOGGER.info(media_id);
        return media_id;
    }

    public static void main(String[] args) throws IOException {

        //获取accesstoken

        //调用上传方法获得media_id
        String path="D:\\pang.png";
        String media_id=upload("access",path,"image");
    }

}