httpclient上传文件方法的封装

/**
     * 设置二进制流实体，params 里面参数值为 file
     * 
     * @param httpPost
     *            httpPsot 请求
     * @param params
     *            请求参数
     * @param file
     *            文件
     */
    public void setMultipartEntityEntity(HttpPost httpPost, JSONObject params, File file) {
        String fileName = getFileName(file);
        InputStream inputStream = null;
        try {
            inputStream = new FileInputStream(file);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        Iterator<String> keys = params.keys();// 遍历 params 参数和值
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();// 新建builder对象
        while (keys.hasNext()) {
            String key = keys.next();
            String value = params.getString(key);
            if (value.equals("file")) {
                builder.addBinaryBody(key, inputStream, ContentType.create("multipart/form-data"), fileName);// 设置流参数
            } else {
                StringBody body = new StringBody(value, ContentType.create("text/plain", Consts.UTF_8));// 设置普通参数
                builder.addPart(key, body);
            }
        }
        HttpEntity entity = builder.build();// 生成entity
        httpPost.setEntity(entity);// 设置 entity
    }