Category Archives: Programming

How to use Spring Security in web application – Part VIII

In this post, we will show how to use Spring Boot Security to login, authorization based on user role, log out, and error handling.

We will be discussing the following use case

  1. A user accesses a home page for an application.
  2. A user enters credentials
  3. If correct credentials, we create a session and verifies the user role. User with USER role sees the user profile page. User with ADMIN role sees the list of users page.
  4. Incorrect credentials, the user will see the login screen once again to enter credentials.
  5. A user clicks on logout, the session is deleted and the user is redirected to the login page.
  6. If a user (of any role) tries to login after logout, the user should be redirected to the appropriate page
  7. In a scenario where a user is neither USER nor ADMIN, he is redirected to the error page
  8. Handling of CSRF token

To completely understand this post, make sure you have gone through my other posts on the Spring Boot series.

  1. Spring Boot REST CRUD API
  2. Swagger Documentation
  3. User Interface using AngularJS

 

Database changes

Since this post involves authorization for users, we have to do some database changes. We will add a couple of tables and respective model classes in our REST API modification.

  • Table role
  • Table user_role

create table role (id int(11) auto_increment primary key not null, role varchar(255) )

create table user_role (user_id int(11) primary key not null, role_id int(11) primary key not null))

user_role the table helps to maintain a many-to-many relationship between the user and role table. We will have only two roles for demo purposes, USER and ADMIN.

Another change we have done in table user is that we have added a field called password_hash to store password set by user/administrator for a user to login. We will be storing a hash password value of the original password that the user will set.

Dependencies

Since we will be using Spring-security for authentication and authorization purposes, we will add the dependency for spring security as follows:

<dependency>   

<groupId>org.springframework.boot</groupId>   

<artifactId>spring-boot-starter-security</artifactId>

</dependency>

Controllers and Web Layer

Other than those changes mentioned, we will demonstrate this post in top-down fashion rather than bottom-up fashion.

So for the web layer, we will define a new controller LoginController and modify our existing MainController.

package com.betterjavacode.benefits.controller;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.betterjavacode.benefits.entities.User;
import com.betterjavacode.benefits.interfaces.UserManager;

/**
*
* @author Yogesh Mali
*
*/
@Controller
public class LoginController {

public static final Logger LOGGER = LogManager.getLogger(LoginController.class);

@Autowired
UserManager userManager;

/**
*
* @param model
* @return
*/
@RequestMapping(value = "/user", method = RequestMethod.GET)
public String userpage(Model model) 
{
  LOGGER.info(" Enter >> userpage() ");
  Authentication auth = SecurityContextHolder.getContext().getAuthentication();
  String name = auth.getName();
  User user = userManager.findUserByEmail(name);
  model.addAttribute("name", user.getFirstname());
  model.addAttribute("userid", user.getId());
  LOGGER.info(" Exit << userpage() ");
  return "user";
}

/**
*
* @return
*/
@RequestMapping(value = { "/login" })
public String login() {
  return "login";
}

/**
*
* @return
*/
@RequestMapping(value = "/403", method = RequestMethod.GET)
public String Error403() {
  return "403";
}
}

As shown in this controller, we have defined a user page, a login page, and an error page (403). A user with the role of either USER or ADMIN or both can access a user page which shows that logged in user’s profile.

Every user irrespective of roles will see the login page for authentication. If there are any errors during authentication or authorization, the user will see an error page displaying access denied page (403).

Source code for login page is as below:

<!DOCTYPE html><!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org">
<head> <title>Benefits Application</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" /> <link rel="stylesheet" type="text/css" th:href="@{/css/login.css}" />  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script></head>
<body>
<div class="container"> <form th:action="@{/login}" method="POST" class="form-signin">
<h3 class="form-signin-heading" th:text="Welcome"></h3>
<input type="text" id="email" name="username"  th:placeholder="Email" class="form-control" style="width:350px"/>
<input type="password"  th:placeholder="Password" id="password" name="password" class="form-control" style="width:350px"/>
<div align="center" th:if="${param.error}">
<p style="font-size: 20; color: #FF1C19;">Email or Password invalid, please verify</p>

</div>
<button class="btn btn-lg btn-primary btn-block" name="Submit" value="Login" type="Submit" th:text="Login" style="width:350px"></button> </form></div>
</body></html>

This login page shows a simple form to input username (email) and password and process that authentication using spring-security database authentication method.

@RequestMapping(value = "/home", method = RequestMethod.GET)
public String homepage(Model model) 
{
  LOGGER.info(" Enter >> homepage() ");
  Authentication auth = SecurityContextHolder.getContext().getAuthentication();
  String name = auth.getName();
  User user = userManager.findUserByEmail(name);
  model.addAttribute("name", user.getFirstname());
  LOGGER.info(" Exit << homepage() ");
  return "index";
}

Changes in MainController are about an authenticated user and passing that user’s first name to model to display in HTML page. UserManager in the service layer has been enhanced to return a user based on username (which is email). We have also added an email to be unique as a constraint in the database.

User page for a user with role USER is nothing but a user profile information that he can edit and update any time.

<html ng-app="benefitApp"><html ng-app="benefitApp"><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Benefit Application</title><script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="/css/bootstrap.css" /><script src="https://code.angularjs.org/1.6.1/angular.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular-route.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular-resource.js"></script><script type="text/javascript" src="./js/app.js"></script></head><body ng-controller="UserCtrl">Hello
<p th:text="${name}"></p>

<div>
<ul class="menu">
<li><a th:href="@{'userProfile/' + ${userid}}">Profile</a></li>
</ul>
<div ng-view="ng-view"></div>
</div>
<div class="input-group">
<div class="controls">    <a ng-click="logout()" class="btn btn-small">Logout</a></div>
</div>
</body></html>

Authentication

Now we have the application ready with all the required backend details for adding the authentication part. Remember we are using spring-security for authentication and authorization of an application.

package com.betterjavacode.benefits;

import javax.sql.DataSource;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.security.SecurityProperties;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.builders.WebSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;

@Configuration
@ComponentScan("com.betterjavacode.benefits.services")
@EnableWebSecurity
@Order(SecurityProperties.ACCESS_OVERRIDE_ORDER)
public class SecurityConfig extends WebSecurityConfigurerAdapter {

public static final Logger LOGGER = LogManager.getLogger(SecurityConfig.class);

@Autowired
private SimpleAuthenticationSuccessHandler loginSuccess;

@Autowired
private LogoutSuccess logoutSuccess;

@Autowired
private BCryptPasswordEncoder bCryptPasswordEncoder;

@Autowired
private DataSource dataSource;

@Value("${spring.queries.users-query}")
private String usersQuery;

@Value("${spring.queries.roles-query}")
private String rolesQuery;

@Autowired
protected void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
LOGGER.info(" Enter >> configureGlobal() ");
auth.jdbcAuthentication()
.usersByUsernameQuery("select email,password_hash,enabled from user where email=?")
.authoritiesByUsernameQuery("select u.email,r.role from user u inner join user_role ur on(u.id=ur.user_id) inner join role r on(r.id=ur.role_id) where u.email=?")
.dataSource(dataSource)
.passwordEncoder(bCryptPasswordEncoder);
LOGGER.info(" Exit << configureGlobal() ");
}

/**
* Handle Login - Authentication and Redirection
*/
@Override
protected void configure(HttpSecurity http) throws Exception {
http.csrf()
.disable()
.authorizeRequests()
.antMatchers("/home")
.hasAuthority("ADMIN")
.antMatchers("/user")
.hasAnyAuthority("USER", "ADMIN")
.and()
.formLogin()
.loginPage("/login")
.successHandler(loginSuccess)
.permitAll()
.and()
.logout()
.logoutSuccessHandler(logoutSuccess)
.deleteCookies("JSESSIONID")
.invalidateHttpSession(false)
.permitAll()
.and()
.exceptionHandling()
.accessDeniedPage("/403");

}

/**
* Exclude resources from user-access
*/
@Override
public void configure(WebSecurity web) throws Exception {
web.ignoring()
.antMatchers("/resources/**", "/static/**", "/css/**", "/js/**", "/images/**");
}
}

What’s happening in this code?

  • When a user with role ADMIN or USER calls either /home or /user pages respectively, the user will need to log in.
  • Once the user inputs credentials, validation of credentials happens against the JDBC database authentication mechanism provided by spring-security.
  • If a user of the role USER tries to access the ADMIN home page, the user sees an error 403 page. Authentication Success Handler handles the redirection strategy.
  • If the user clicks the LOGOUT button on the page he is on, the session gets deleted and the user logs out of the application. The user will see the login page. All the cookies will be deleted. Logout Success Handler handles the redirection.

 

Changes in AngularJS User Interface Controller

As shown in user.html page, once the user with role USER is logged in, he sees URL for his profile information. If a user clicks this URL, the user sees his or her profile information. This page has a controller called UserCtrl which basically handles the logout on this initial page. User Profile is shown on userprofile.html page which has singleusercontroller. This angular js controller handles updating user profile information or logout. The github repository contains the rest of the code.

Handling CSRF Token

There are two ways we can handle Cross-Site Request Forgery token in the Spring application. The first way is by disabling this token generation. This is not a recommended approach as this put your application to possible CSRF security attacks for hackers. If you are just doing this for demo purposes, you can disable this in SecurityConfig.java by calling http.csrf().disable().

As Spring points out, a request coming through browsers should contain CSRF Protection.

We will be using spring security to handle CSRF token on the server-side rather than on the client-side.  So every request that comes to the server, we will add a CSRF token and then verified. Angular JS verifies the cookie for the CSRF token before a user can post any request.

Add a CSRF Filter Class

We will add a filter that will handle setting of CSRF token in a cookie. Angular JS expects a cookie name to be as XSRF-TOKEN. This class will look like below:

public class CSRFHeaderFilter extends OncePerRequestFilter {

@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException 
{
  CsrfToken csrf = (CsrfToken) request.getAttribute(CsrfToken.class.getName());
  if (csrf != null) 
  {
    Cookie cookie = WebUtils.getCookie(request, "XSRF-TOKEN");
    String token = csrf.getToken();
    if (cookie == null || token != null && !token.equals(cookie.getValue())) 
    {
      cookie = new Cookie("XSRF-TOKEN", token);
      cookie.setPath("/");
      response.addCookie(cookie);
    }
  }
  filterChain.doFilter(request, response);
}

}

Now we will enable csrf token in SecurityConfig as shown below

.and()
.csrf()
.csrfTokenRepository(csrfTokenRepository())
.and()
.addFilterAfter(new CSRFHeaderFilter(), CsrfFilter.class);

What is csrfTokenRepository?

We tell spring-security to expect CSRF token in the format that Angular wants to send it back , a header called X-XSRF-TOKEN instead of default X-CSRF-TOKEN. With these changes, we don’t have to do anything on client side.

private CsrfTokenRepository csrfTokenRepository() 
{
  HttpSessionCsrfTokenRepository repository = new HttpSessionCsrfTokenRepository();
  repository.setHeaderName("X-XSRF-TOKEN");
  return repository;
}

Demo

In this post, we showed how to use spring security for authentication and authorization. Now we will show how to run the application. Once the application is built and run from eclipse, access the page https://localhost:8443/home , we will see below screen:

Using Spring Security in web application - login screenIt will be the same screen if you access https://localhost:8443/user. Now if we enter credentials of an admin user, we will see below screen:

Using Spring Security in web application - admin screen

User screen will be as below:

Using Spring Security - User Screen

If you click logout, it will log the user out and show login screen again. In this way, we showed how we can use spring security for authentication and authorization. Code for this is available at Github repository.

References

  1. Spring Boot Security
  2. Login Page Angular JS and Spring Security

 

Microservices – A Primer

In this post, I cover a primer about microservices.

What is Microservices? A Primer about Microservices

Wikipedia definition says

Microservices is a variant of the service-oriented architecture (SOA) architectural style that structures an application as a collection of loosely coupled services.

Firstly, there is no official definition of Microservices by industry standards. It’s a recent phenomenon in the software industry to architect the new software which should be lightweight, easier to deploy, and scale, easier to refactor individually, and could work independently.

However, to understand in detail, you can definitely read Martin Fowler’s Microservices or Chris Richardson’s Microservices.

Secondly, microservices are small services that can run independently but can also easily communicate with other services.

Microservice Architecture vs Monolithic Architecture

In a traditional monolithic architecture style, there is a single application with a single code base. An application contains a number of modules that are interrelated and can have external dependencies. It’s a multi-tier enterprise application and has been used to build software for long.

Above all, the microservice architecture style was born out of a need to build an application that could easily be supported for mobile applications. The older style was not easy to support for mobile and new generation way to the handling of data. Any large enterprise application can be easily built using the microservices architecture style. A famous example is NETFLIX.

How to identify the Microservice Architecture Pattern?

A simple ground rule of the microservice architecture pattern is to build a standalone service that can be run without depending on any other service. In other words, a large application can have more than one service talking to each other, communicating with their own databases, but still performing the business logic. Databases are used to ensure loose coupling of services.

For instance, a large enterprise e-commerce application can consist of the following services

  1. Backend service REST API to manage data
    1. Account Service
    2. Shipment Service
    3. Inventory Service
  2. Runtime service to handle runtime and backend data to process business logic
  3. Logging service
  4. Error Handling service
  5. Session service

Additionally, UI for the e-commerce application can be built independently to use backend services to show/edit data.

By standards, there are few rules to identify microservices patterns

  1. Decomposition by business capability
  2. Database per service pattern
  3. API gateway pattern
  4. Client-side discovery and Server-side discovery

Pros and Cons of Microservices

Pros

  1. Deployability – Easier to deploy and one can deploy them independently, without affecting other services.
  2. Reliability – A fault in the service can only bring down that service. Depending on the handling of the fault in the application, the rest of the application can still continue to work.
  3. Scalability – Similarly, the scaling of each microservice will depend on requirements using clusters and grids.
  4. Availability – Dispatching the patch or newer version of service requires less downtime compared to regular monolithic applications.
  5. Management – Easier to manage
  6. Design and Development – Each service helps the developer to manage the service easily without worrying about other services.

Cons

  1. Performance – All services involved in the application have to communicate with each other over the network and that could hamper the performance.
  2. Testability – Automated tests are harder to manage and run.
  3. Memory usage – Possible duplicate data across services and a lot of duplication in the cache.

References

In conclusion, I covered a primer about microservices. If you want to read more about Microservices at following links:

  1. Microservices by Chris Richardson
  2. Microservices by Martin Fowler
  3. Stackoverflow post about microservices

Lastly, if you enjoyed this post, subscribe to my blog.

 

Design Pattern – Prototype Pattern – Part VI

In this post, I want to show how to use Prototype design pattern. If you want to read about previous posts related to design patterns, series of posts about design patterns are

  1. Introduction to design patterns
  2. Singleton Pattern
  3. Factory Pattern
  4. Abstract Factory Pattern
  5. Builder Pattern

The prototype design pattern will cover the creation design pattern that we have been writing about till now.

When to use?

Since this is a creational design pattern, this is used when decision is to reduce the creation cost of object in a standard way. There can be argument about how this is then different from abstract factory pattern. The key benefit of Prototype design pattern is that it optimizes the use case where multiple objects of same type will have mostly same data.

Major example is reading configuration data from a file/database over a network. Also if you want to hide the logic of creating new instance from the client.

How to use?

Firstly, in this pattern, there is an interface of Prototype that has method for clone and any concrete class implementing this interface, implements the method to clone the object.

 

public interface Car {

Car clone();

}

We have an interface Car which we will implement in our concrete classes.

package com.bettterjavacode.designpatterns.prototypeexample;

public class Toyota implements Car 
{

    private final String CARNAME = "Toyota";

    public Car clone() 
    {
       return new Toyota();
    }

    @Override
    public String toString() 
    {
      return CARNAME;
    }

}

 

We will have a factory class that will get us a prototype based on type of object we have passed. This will look like below:

package com.bettterjavacode.designpatterns.prototypeexample;

import java.util.HashMap;
import java.util.Map;

public class CarFactory
{

   private static final Map<String, Car> prototypes = new HashMap<String, Car>();

   static 
   {
     prototypes.put("toyota", new Toyota());
     prototypes.put("lexus", new Lexus());
     prototypes.put("bmw", new BMW());
   }

   public static Car getPrototype(String type) 
   {
      return prototypes.get(type).clone();
   }
}

 

Therefore, our demo class will pass the type of car as an argument to print the carname. That will look like below:

package com.betterjavacode.designpatterns;

import com.bettterjavacode.designpatterns.prototypeexample.Car;
import com.bettterjavacode.designpatterns.prototypeexample.CarFactory;

public class PrototypeDemo 
{
   public static void main(String[] args) 
   {
      if (args.length > 0) 
      {
         for (String type : args) 
         {
            Car prototype = CarFactory.getPrototype(type);
            if (prototype != null) 
            {
               System.out.println(prototype);
            }
         }
      } 
      else 
      {
         System.out.println(" Run again with arguments");
      }
   }
}

Conclusion

In conclusion, we showed how to use prototype design pattern. The code for this is available here

References

  1. Design Patterns – Prototype
  2. Prototype Pattern

Design Patterns – Builder Pattern – Part V

Continuing the series of posts about design patterns, we will talk about builder pattern in this post. Builder pattern is of type creational design pattern. One of the major uses of Builder pattern is when there are too many constructor parameters to handle.

In my previous post, I showed how to use factory pattern.

When to use Builder Pattern?

Builder pattern enforces a step-by-step approach to create a complex object. The object can not be used till it’s a finished product. It helps to encapsulate complex creation logic. One of the examples from real time is file creation with a format. If you are creating a file in certain format (example xml, csv), you can use builder pattern to create a simple logical approach to creating the file.

How to use Builder Pattern?

Lately working on a project to build an EDI file to transfer between customer, I have to create a file of format 834. So 834 file format varies according to different health insurance carrier. This file format contains headers, records and trailers. Headers indicate different paradigm about the file and the customer and who is sending it. To show example of this pattern, I will use one of the headers of this file format and how it can be created using builder pattern.

One of the headers is called the Transactional Group Header. This header looks like below in a real file

ST*834*5432853*005010X220A1~

First field “ST” indicates that it is a transactional group. All the records for one customer can lie between ST and SE. 834 is a transaction code for file format. Since this is 834 file format, code is 834. 5432853 is a unique transaction control number, this can be anything between 4 digits in length to a maximum 9 digits in length. 005010X220A1 is an implementation reference number.

Our implementation of the class with have fields for each of these fields from a header, a private constructor and a static builder class. This is shown below:

public class TransactionalHeader implements Serializable {
private static final long serialVersionUID = 7517644545656169045L;

private String st;

private String transactioncode;

private String transactioncontrolnumber;

private String implementationreference;

public static class Builder {

private String st;

private String transactioncode;

private String transactioncontrolnumber;

private String implementationreference;

public Builder st(String st) {

this.st = st; return this;

}

public Builder transactioncode(String transactioncode) {

this.transactioncode = transactioncode; return this;

}

public Builder transactioncontrolnumber(String transactioncontrolnumber) {                            this.transactioncontrolnumber = transactioncontrolnumber; return this;

}

public Builder implementationreference(String implementationreference) {                                this.implementationreference = implementationreference; return this;

}

public TransactionalHeader build() {

return new TransactionalHeader(this);

}

}

private TransactionalHeader(Builder builder) {

this.st = builder.st;

this.transactioncode = builder.transactioncode;

this.transactioncontrolnumber = builder.transactioncontrolnumber;

this.implementationreference = builder.implementationreference;

}

public String toString() {

String result = "";

StringBuffer sb = new StringBuffer();

sb.append(st);

sb.append(FileUtil.FIELD_SPLITTER);

sb.append(transactioncode);

sb.append(FileUtil.FIELD_SPLITTER);

sb.append(transactioncontrolnumber);

sb.append(FileUtil.FIELD_SPLITTER);

sb.append(implementationreference);

sb.append("~");

result = sb.toString();

return result;

}

}

 

This was our builder class. Let’s create a demo class that will use this builder class to build an object that will give us a transactional header in the file. This will look like below:

public String getTransactionalHeader() {

String result = "";

TransactionalHeader th = new TransactionalHeader.Builder()

.st("ST")

.transactioncode(TRANSACTION_IDENTIFIER_CODE)

.transactioncontrolnumber(FileUtil.getTransactionControlNumber())

.implementationreference("005010X220A1").build();

result = th.toString();

return result;

}

 

Conclusion

In this way, we can use builder design patterns to construct complex objects. One of the easy ways to identify when to use this design pattern is when you have more than 4 or more parameters in your constructor.

The code for this post is available to download here.

 

How To: AngularJS User Interface to CRUD Spring Boot REST API

In this post, we will add an user interface using AngularJS to the REST api we created here.

Controller for home page

First we will create a controller in Spring Boot rest API to call our home page. All the requests that will come to web server, will go through this controller and the controller will return a home page for the request based on path.

MainController.java will look like below:

package com.betterjavacode.benefits.controller;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class MainController 
{

     public static final Logger LOGGER = LogManager.getLogger(MainController.class);

     @RequestMapping(value = "/home", method = RequestMethod.GET)
     public String homepage() 
     {
         LOGGER.info(" Enter >> homepage() ");
         return "index";
     }
}

Any request coming to https://localhost:8443/home will return a page from index.html.

Create a Home Page

Now, we will create an index.html page. We will also be using angular JS framework as part of this home page so that we can build a single page application. If you are not aware of Angular JS or new to this framework, you can read about it AngularJS. One thing to remember while creating this page is a directory structure. Lot of issues that arise to create html pages are because of directory structure. Directory structure will look like below:

directorystructure

The home page index.html page is under main/resources/templates/ directory and it looks like below

<html ng-app="benefitApp">

<head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /><title>Benefit Application</title>

<script>document.write('<base href="' + document.location + '" />');</script>

<link rel="stylesheet" href="/css/bootstrap.css" />

<script src="https://code.angularjs.org/1.6.1/angular.js"></script>

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular-route.js"></script>

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular-resource.js"></script>

<script type="text/javascript" src="./js/app.js"></script>

</head>

<body ng-controller="MainCtrl">

Hello {{name}}!
<div>
<ul class="menu">
<li><a href="listUser">user-list</a></li>
<li><a href="listCompany">company-list</a></li>
</ul>
<div ng-view="ng-view"></div>
</div>
</body></html>

Home page shows that this is an angular app with name benefitApp. This also declares a controller MainCtrl with an angular view. Important to see we are importing angular.js, angular-route.js and angular-resource.js modules. Click on user-list or company-list, will show list of users and list of companies respectively.

Create a controller

Now to handle the controller (MainCtrl), we added in index.html, we will add app.js which will declare the controller. This javascript file also contains config data to handle all the routing of pages. That’s why we will be importing “ngRoute” and “ngResource” angular modules.

var app = angular.module('benefitApp', ['ngRoute','ngResource']);

var app = angular.module('benefitApp', ['ngRoute','ngResource']);
app.controller('MainCtrl', function($scope, $routeParams) {

$scope.name = 'World';

$scope.$routeParams = $routeParams;

})

 

Through out the interaction on web pages, we will be using different controllers for editing user or company information and creating user or company. The same file app.js will also handle routing of these pages which is shown below

app.config(function($routeProvider,$locationProvider) {

$locationProvider.html5Mode(true);

$routeProvider.when('/listUser',

{templateUrl: 'views/listUser.html', controller: 'userController'});

$routeProvider.when('/listCompany',

{templateUrl: 'views/listCompany.html', controller: 'companyController'});

$routeProvider .when('/editUser/:userId',

{ templateUrl : 'views/editUser.html' }) ;

$routeProvider .when('/editCompany/:companyId',

{ templateUrl : 'views/editCompany.html' }) ;

$routeProvider.when('/createUser',

{templateUrl:'views/createUser.html'});

$routeProvider.when('/createCompany',

{templateUrl:'views/createCompany.html'});

});

Rest of the code showing all controllers’ logic has been skipped for post purposes. It is available on github repository.

UserController or CompanyController are calling rest apis which we have built using Spring boot.

Demo

Now build the code and run our embedded tomcat webserver. Fire up the url https://localhost:8443/home – it will look like below:

Home Page created with AngularJS for CRUD REST API

Click on user-list and it will show list of users inside the same page as below:

List of User Page created with AngularJS

Click on edit button and we will see a form to update user information:

edituserpage

Download –

In this post, we showed how to create a simple CRUD user interface using angular JS for Spring Boot REST API. The code for this is available in repository