Tomcat web service authentication

In order to set authentication to Tomcat web service by username and password, these 2 steps are required: 

1 - Add these codes to web.xml of web service:
<security-constraint>
    <web-resource-collection>
      <web-resource-name>TestWS</web-resource-name>
      <url-pattern>/services/TestWS</url-pattern>
    </web-resource-collection>
    <auth-constraint>
      <role-name>testrole</role-name>
    </auth-constraint>
  </security-constraint>

2- Add these codes to tomcat-user.xml of Tomcat:
<tomcat-users>
   <user username="testuser" password="testpwd" roles="testrole"/>
</tomcat-users>