Sending Request from Angular to Java Servlet

Question

I have an angular app and a java servlet backend. what I need to do is send httpRequest from angular to backend. I am using httpClient to do that.
MyService.ts

import { Injectable, EventEmitter } from '@angular/core';
import { HttpClient } from '@angular/common/http';
@Injectable()
export class MyServices {

  constructor(private httpClient: HttpClient) {}
  public getTables(num: number) {
    return this.httpClient.post("url/to/backend",JSON.stringify({number: num}));
  }
}

and in my servlet I receive the request but when I use requset.getParameter to get the number value it returns null. I'm sure when I read the request body it returns:

"{"number":3}"

when I use request.getParametersName it returns null again. does anyone know what I am doing wrong? and am I using the right tool for sending an httpRequest?

@mast3rd3mon I tried to do it without stringifying the body but it made no difference. — Bahman Rouhani
– Bahman Rouhani, Commented Jan 24, 2018 at 13:00
Could you solve it? I'm having the exact same problem, with the exact same situation. Reading the body through getReader() shows the JSON, but with getParameter() I don't seem to be able to get them. Thanks. — Angel D.
– Angel D., Commented Jan 17, 2019 at 19:36

mast3rd3mon · Accepted Answer · 2018-01-24 13:03:07Z

1

Try swapping the code to return this.httpClient.post("url/to/backend",{'number': num}); as you shouldnt stringify the body if the web handler expects a json body

answered Jan 24, 2018 at 13:03

mast3rd3mon

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7 Comments

mast3rd3mon Over a year ago

have you tried logging out the whole body? instead of just what the value is?

Bahman Rouhani Over a year ago

I tried that. I can log out the whole body with getReader(). as I said in the original question it logs "{"number":3"}" . I can use that but I don't think it's very good practice.

Bahman Rouhani Over a year ago

I haven't tried that. do you mean parsing it back using Gson?

mast3rd3mon Over a year ago

well you said the logged value has quotes around it which suggests its a string, not json

mast3rd3mon Over a year ago

my best guess is either the app isnt rebuilding properly when you remove the stringify or the java server code forces it to be a string

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ASWIN S · Accepted Answer · 2020-02-29 17:36:51Z

1

Not an expert in this, but when you are sending a request in post method the data is in body. In your servlet you are checking it in request parameter. I think you have to check in request body. I use spring framework than servlet, so can't provide exact code.

answered Feb 29, 2020 at 17:36

ASWIN S

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