Rest Assured 400 Bad Request

I writing an automation code in rest assured but it return 400 Bad Request and I don't know how to debug it. Hope someone can help.

In postman, i must specify the username and password using raw approach. It will fail on form-data. How to specify raw data in rest-assured?

Curl:

curl --location --request POST 'http://127.0.0.1:8010/api/v1/account/webapi/account/users/secure/webEncryptLogin?checkHash=false%0A' \
--header 'device_token: wap' \
--header 'Content-Type: application/json' \
--data-raw '{
  "username": "peter1",
  "password": "SomeSecretPassword"
}'

Rest Assured Java Code:

given().
                    contentType("application/json").
                    queryParam("checkHash", "false").
                    header("device_token", "wap").
                    params("username", "peter1", "password","SomeSecretPassword").
            when().
                    post("http://127.0.0.1:8010/api/v1/account/webapi/account/users/secure/webEncryptLogin").
            then().
                    log().ifError().
                    assertThat().
                    statusCode(200);

Questions:

1. Anything wrong with the code?
2. How to specify raw data with rest assured?
3. How to extract access token into string?

Change params to body() method