发帖请求时排球错误

Question

我正在向服务器发帖子，我得到了这个例外。请帮我

这是我的登录代码 （我发送JSON）

RequestQueue queue = Volley.newRequestQueue(this);

    StringRequest stringRequest = new StringRequest(Request.Method.POST, loginLink, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            progressDialog.dismiss();
            Toast.makeText(LoginActivity.this, "response\n" + response, Toast.LENGTH_LONG).show();
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            progressDialog.dismiss();
            Toast.makeText(LoginActivity.this, "exception\n" + error.getMessage(), Toast.LENGTH_SHORT).show();
        }
    }) 

  {
        @Override
        public byte[] getBody() throws AuthFailureError {
            return loginData.getBytes();
        }

        @Override
        public String getBodyContentType() {
            return "application/json";
        }
    };
    /*return "application/json; charset=utf-8";*/
    queue.add(stringRequest);