application/x-www-form-urlencoded; charset=UTF-8

// json对象
{ a : 3, b : 2 }
// 将json对象处理为
"a=3&b=2"

application/json

// json对象
{a: 3,c: 2}

/**
  * 将application/json转换为application/x-www-form-urlencoded
  * @param data
  */
 handlerPostParams(data) {
  const params = [];
  for (const key in data) {
   if (data[key] && !isNull(data[key])) {
    if (data[key] instanceof Array) {
     for (let i = 0; i < data[key].length; i++) {
      if (data[key][i] && !isNull(data[key][i])) {
       const value = data[key][i];
       const name = key + '[' + i + ']';
       const innerObj = {};
       innerObj[name] = value;
       params.push(this.handlerPostParams(innerObj));
      }
     }
    } else if (data[key] instanceof Object) {
     for (const k in data[key]) {
      if (data[key][k] && !isNull(data[key][k])) {
       const value = data[key][k];
       const name = key + '[' + k + ']';
       const innerObj = {};
       innerObj[name] = value;
       params.push(this.handlerPostParams(innerObj));
      }
     }
    } else {
     const param = encodeURIComponent(key) + '=' + encodeURIComponent(data[key]);
     params.push(param);
    }
   }
  }
  return params.join('&');
 }