RESTful Web Services with Spring and Spring Boot

Building RESTful web services with Spring Boot is fun. In this course, we will discover why Spring, Spring MVC and Spring Boot is becoming the best framework combination to develop RESTful web services.

You will learn

• What is a RESTful Web Service?
• How to implement RESTful Web Services with Spring and Spring Boot?
• What are the best practices in designing RESTful Web Services?
• How to design Resources and GET, POST and DELETE operations?
• How to implement Validation for RESTful Web Services?
• How to implement Exception Handling for RESTful Web Services?
• What is HATEOAS? How to implement HATEOAS for a Resource?
• What are the different approach in versioning RESTful Services?
• How to use Postman to execute RESTful Service Requests?
• How to implement basic authentication with Spring Security?
• How to implement filtering for RESTful Services?
• How to monitor RESTful Services with Spring Boot Actuator?
• How to document RESTful Web Services with Swagger?
• How to connect RESTful Services to a backend with JPA?

Steps

Basics of RESTful Services

• Step 01 - Initializing a RESTful Services Project with Spring Boot
• Step 02 - Understanding the RESTful Services we would create in this course
• Step 03 - Creating a Hello World Service
• Step 04 - Enhancing the Hello World Service to return a Bean
• Step 05 - Quick Review of Spring Boot Auto Configuration and Dispatcher Servlet - What's happening in the background?
• Step 06 - Enhancing the Hello World Service with a Path Variable
• Step 07 - Creating User Bean and User Service
• Step 08 - Implementing GET Methods for User Resource
• Step 09 - Implementing POST Method to create User Resource
• Step 10 - Enhancing POST Method to return correct HTTP Status Code and Location URI
• Step 11 - Implementing Exception Handling - 404 Resource Not Found
• Step 12 - Implementing Generic Exception Handling for all Resources
• Step 13 - Exercise : User Post Resource and Exception Handling
• Step 14 - Implementing DELETE Method to delete a User Resource
• Step 15 - Implementing Validations for RESTful Services
• Step 16 - Implementing HATEOAS for RESTful Services

Advanced RESTful Service Features

• Step 17 - Overview of Advanced RESTful Service Features
• Step 18 - Internationalization for RESTful Services
• Step 19 - Content Negotiation - Implementing Support for XML
• Step 20 - Configuring Auto Generation of Swagger Documentation
• Step 21 - Introduction to Swagger Documentation Format
• Step 22 - Enhancing Swagger Documentation with Custom Annotations
• Step 23 - Monitoring APIs with Spring Boot Actuator
• Step 24 - Implementing Static Filtering for RESTful Service
• Step 25 - Implementing Dynamic Filtering for RESTful Service
• Step 26 - Versioning RESTful Services - Basic Approach with URIs
• Step 27 - Versioning RESTful Services - Header and Content Negotiation Approaches
• Step 28 - Implementing Basic Authentication with Spring Security

Connecting RESTful Service to JPA

• Step 29 - Overview of Connecting RESTful Service to JPA
• Step 30 - Creating User Entity and some test data
• Step 31 - Updating GET methods on User Resource to use JPA
• Step 32 - Updating POST and DELETE methods on User Resource to use JPA
• Step 33 - Creating Post Entity and Many to One Relationship with User Entity
• Step 34 - Implementing a GET service to retrieve all Posts of a User
• Step 35 - Implementing a POST service to create a Post for a User

What You Will Need?

We will help you install

• Java 8
• Eclipse
• Maven
• Embedded Tomcat
• Postman REST Services Client

Useful Links

• POSTMAN - http://www.getpostman.com

Links from course examples

• Basic Resources
  • http://localhost:8080/hello-world
  • http://localhost:8080/hello-world-bean
  • http://localhost:8080/hello-world/path-variable/Ranga
  • http://localhost:8080/users/
  • http://localhost:8080/users/1
• JPA Resources
  • http://localhost:8080/jpa/users/
  • http://localhost:8080/jpa/users/1
  • http://localhost:8080/jpa/users/10001/posts
• Filtering
  • http://localhost:8080/filtering
  • http://localhost:8080/filtering-list
• Actuator
  • http://localhost:8080/actuator
• Versioning
  • http://localhost:8080/v1/person
  • http://localhost:8080/v2/person
  • http://localhost:8080/person/param
    • params=[version=1]
  • http://localhost:8080/person/param
    • params=[version=2]
  • http://localhost:8080/person/header
    • headers=[X-API-VERSION=1]
  • http://localhost:8080/person/header
    • headers=[X-API-VERSION=2]
  • http://localhost:8080/person/produces
    • produces=[application/vnd.company.app-v1+json]
  • http://localhost:8080/person/produces
    • produces=[application/vnd.company.app-v2+json]
• Swagger
  • http://localhost:8080/swagger-ui.html
  • http://localhost:8080/v2/api-docs
• H2-Console
  • http://localhost:8080/h2-console

Table Structure

create table user (
id integer not null, 
birth_date timestamp, 
name varchar(255), 
primary key (id)
);

create table post (
id integer not null, 
description varchar(255), 
user_id integer, 
primary key (id)
);

alter table post 
add constraint post_to_user_foreign_key
foreign key (user_id) references user;

Example Requests

GET http://localhost:8080/users

[
    {
        "id": 1,
        "name": "Adam",
        "birthDate": "2017-07-19T04:40:20.796+0000"
    },
    {
        "id": 2,
        "name": "Eve",
        "birthDate": "2017-07-19T04:40:20.796+0000"
    },
    {
        "id": 3,
        "name": "Jack",
        "birthDate": "2017-07-19T04:40:20.796+0000"
    }
]

GET http://localhost:8080/users/1

{
    "id": 1,
    "name": "Adam",
    "birthDate": "2017-07-19T04:40:20.796+0000"
}

POST http://localhost:8080/users

{
    "name": "Ranga",
    "birthDate": "2000-07-19T04:29:24.054+0000"
}

GET http://localhost:8080/users/1000

• Get request to a non existing resource.
• The response shows default error message structure auto configured by Spring Boot.

{
    "timestamp": "2017-07-19T05:28:37.534+0000",
    "status": 404,
    "error": "Not Found",
    "message": "id-500",
    "path": "/users/500"
}

GET http://localhost:8080/users/1000

• Get request to a non existing resource.
• The response shows a Customized Message Structure

{
    "timestamp": "2017-07-19T05:31:01.961+0000",
    "message": "id-500",
    "details": "Any details you would want to add"
}

POST http://localhost:8080/users with Validation Errors

Request

{
    "name": "R",
    "birthDate": "2000-07-19T04:29:24.054+0000"
}

Response - 400 Bad Request

{
    "timestamp": "2017-07-19T09:00:27.912+0000",
    "message": "Validation Failed",
    "details": "org.springframework.validation.BeanPropertyBindingResult: 1 errors\nField error in object 'user' on field 'name': rejected value [R]; codes [Size.user.name,Size.name,Size.java.lang.String,Size]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [user.name,name]; arguments []; default message [name],2147483647,2]; default message [Name should have atleast 2 characters]"
}

GET http://localhost:8080/users/1 with HATEOAS

{
    "id": 1,
    "name": "Adam",
    "birthDate": "2017-07-19T09:26:18.337+0000",
    "_links": {
        "all-users": {
            "href": "http://localhost:8080/users"
        }
    }
}

XML Representation of Resources

GET http://localhost:8080/users

• Accept application/xml

<List>
    <item>
        <id>2</id>
        <name>Eve</name>
        <birthDate>2017-07-19T10:25:20.450+0000</birthDate>
    </item>
    <item>
        <id>3</id>
        <name>Jack</name>
        <birthDate>2017-07-19T10:25:20.450+0000</birthDate>
    </item>
    <item>
        <id>4</id>
        <name>Ranga</name>
        <birthDate>2017-07-19T10:25:20.450+0000</birthDate>
    </item>
</List>

POST http://localhost:8080/users

• Accept : application/xml
• Content-Type : application/xml

Request

<item>
        <name>Ranga</name>
        <birthDate>2017-07-19T10:25:20.450+0000</birthDate>
</item>

Response

• Status - 201 Created

Versioning

• Media type versioning (a.k.a “content negotiation” or “accept header”)
  • GitHub
• (Custom) headers versioning
  • Microsoft
• URI Versioning
  • Twitter
• Request Parameter versioning
  • Amazon
• Factors
• URI Pollution
• Misuse of HTTP Headers
• Caching
• Can we execute the request on the browser?
• API Documentation
• No Perfect Solution

More

• https://www.mnot.net/blog/2011/10/25/web_api_versioning_smackdown
• http://urthen.github.io/2013/05/09/ways-to-version-your-api/
• http://stackoverflow.com/questions/389169/best-practices-for-api-versioning
• http://www.lexicalscope.com/blog/2012/03/12/how-are-rest-apis-versioned/
• https://www.3scale.net/2016/06/api-versioning-methods-a-brief-reference/

Resources and URI Mappings

• Retrieve all Users - GET /users

• Create a User - POST /users

• Retrieve one User - GET /users/{id} -> /users/1

• Delete a User - DELETE /users/{id} -> /users/1

• Retrieve all posts for a User - GET /users/{id}/posts

• Create a posts for a User - POST /users/{id}/posts

• Retrieve details of a post - GET /users/{id}/posts/{post_id}

Complete Code Example

/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.in28minutes.rest.webservices</groupId>
	<artifactId>restful-web-services</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>restful-web-services</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.0.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<!--<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-security</artifactId>
		</dependency>-->

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-actuator</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.data</groupId>
			<artifactId>spring-data-rest-hal-browser</artifactId>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-hateoas</artifactId>
		</dependency>

		<dependency>
			<groupId>com.fasterxml.jackson.dataformat</groupId>
			<artifactId>jackson-dataformat-xml</artifactId>
		</dependency>
		
		<dependency>
			<groupId>io.springfox</groupId>
			<artifactId>springfox-swagger2</artifactId>
			<version>2.4.0</version>
		</dependency>

		<dependency>
			<groupId>io.springfox</groupId>
			<artifactId>springfox-swagger-ui</artifactId>
			<version>2.4.0</version>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
		</dependency>

		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
			<scope>runtime</scope>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>spring-snapshots</id>
			<name>Spring Snapshots</name>
			<url>https://repo.spring.io/snapshot</url>
			<snapshots>
				<enabled>true</enabled>
			</snapshots>
		</repository>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
			<snapshots>
				<enabled>false</enabled>
			</snapshots>
		</repository>
	</repositories>

	<pluginRepositories>
		<pluginRepository>
			<id>spring-snapshots</id>
			<name>Spring Snapshots</name>
			<url>https://repo.spring.io/snapshot</url>
			<snapshots>
				<enabled>true</enabled>
			</snapshots>
		</pluginRepository>
		<pluginRepository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
			<snapshots>
				<enabled>false</enabled>
			</snapshots>
		</pluginRepository>
	</pluginRepositories>


</project>

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/exception/CustomizedResponseEntityExceptionHandler.java

package com.in28minutes.rest.webservices.restfulwebservices.exception;

import java.util.Date;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;

import com.in28minutes.rest.webservices.restfulwebservices.user.UserNotFoundException;

@ControllerAdvice
@RestController
public class CustomizedResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {

	@ExceptionHandler(Exception.class)
	public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
		ExceptionResponse exceptionResponse = new ExceptionResponse(new Date(), ex.getMessage(),
				request.getDescription(false));
		return new ResponseEntity(exceptionResponse, HttpStatus.INTERNAL_SERVER_ERROR);
	}

	@ExceptionHandler(UserNotFoundException.class)
	public final ResponseEntity<Object> handleUserNotFoundException(UserNotFoundException ex, WebRequest request) {
		ExceptionResponse exceptionResponse = new ExceptionResponse(new Date(), ex.getMessage(),
				request.getDescription(false));
		return new ResponseEntity(exceptionResponse, HttpStatus.NOT_FOUND);
	}
	
	@Override
	protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {
		ExceptionResponse exceptionResponse = new ExceptionResponse(new Date(), "Validation Failed",
				ex.getBindingResult().toString());
		return new ResponseEntity(exceptionResponse, HttpStatus.BAD_REQUEST);
	}	
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/exception/ExceptionResponse.java

package com.in28minutes.rest.webservices.restfulwebservices.exception;

import java.util.Date;

public class ExceptionResponse {
	private Date timestamp;
	private String message;
	private String details;

	public ExceptionResponse(Date timestamp, String message, String details) {
		super();
		this.timestamp = timestamp;
		this.message = message;
		this.details = details;
	}

	public Date getTimestamp() {
		return timestamp;
	}

	public String getMessage() {
		return message;
	}

	public String getDetails() {
		return details;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/filtering/FilteringController.java

package com.in28minutes.rest.webservices.restfulwebservices.filtering;

import java.util.Arrays;
import java.util.List;

import org.springframework.http.converter.json.MappingJacksonValue;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import com.fasterxml.jackson.databind.ser.FilterProvider;
import com.fasterxml.jackson.databind.ser.impl.SimpleBeanPropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;

@RestController
public class FilteringController {

	// field1,field2
	@GetMapping("/filtering")
	public MappingJacksonValue retrieveSomeBean() {
		SomeBean someBean = new SomeBean("value1", "value2", "value3");

		SimpleBeanPropertyFilter filter = SimpleBeanPropertyFilter.filterOutAllExcept("field1", "field2");

		FilterProvider filters = new SimpleFilterProvider().addFilter("SomeBeanFilter", filter);

		MappingJacksonValue mapping = new MappingJacksonValue(someBean);

		mapping.setFilters(filters);

		return mapping;
	}

	// field2, field3
	@GetMapping("/filtering-list")
	public MappingJacksonValue retrieveListOfSomeBeans() {
		List<SomeBean> list = Arrays.asList(new SomeBean("value1", "value2", "value3"),
				new SomeBean("value12", "value22", "value32"));

		SimpleBeanPropertyFilter filter = SimpleBeanPropertyFilter.filterOutAllExcept("field2", "field3");

		FilterProvider filters = new SimpleFilterProvider().addFilter("SomeBeanFilter", filter);

		MappingJacksonValue mapping = new MappingJacksonValue(list);

		mapping.setFilters(filters);

		return mapping;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/filtering/SomeBean.java

package com.in28minutes.rest.webservices.restfulwebservices.filtering;

import com.fasterxml.jackson.annotation.JsonFilter;

@JsonFilter("SomeBeanFilter")
public class SomeBean {
	
	private String field1;
	
	private String field2;
	
	private String field3;

	public SomeBean(String field1, String field2, String field3) {
		super();
		this.field1 = field1;
		this.field2 = field2;
		this.field3 = field3;
	}

	public String getField1() {
		return field1;
	}

	public void setField1(String field1) {
		this.field1 = field1;
	}

	public String getField2() {
		return field2;
	}

	public void setField2(String field2) {
		this.field2 = field2;
	}

	public String getField3() {
		return field3;
	}

	public void setField3(String field3) {
		this.field3 = field3;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/helloworld/HelloWorldBean.java

package com.in28minutes.rest.webservices.restfulwebservices.helloworld;

public class HelloWorldBean {

	private String message;

	public HelloWorldBean(String message) {
		this.message = message;
	}

	public String getMessage() {
		return message;
	}

	public void setMessage(String message) {
		this.message = message;
	}

	@Override
	public String toString() {
		return String.format("HelloWorldBean [message=%s]", message);
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/helloworld/HelloWorldController.java

package com.in28minutes.rest.webservices.restfulwebservices.helloworld;

import java.util.Locale;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.MessageSource;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RestController;

//Controller
@RestController
public class HelloWorldController {
	
	@Autowired
	private MessageSource messageSource; 

	@GetMapping(path = "/hello-world")
	public String helloWorld() {
		return "Hello World";
	}

	@GetMapping(path = "/hello-world-bean")
	public HelloWorldBean helloWorldBean() {
		return new HelloWorldBean("Hello World");
	}
	
	///hello-world/path-variable/in28minutes
	@GetMapping(path = "/hello-world/path-variable/{name}")
	public HelloWorldBean helloWorldPathVariable(@PathVariable String name) {
		return new HelloWorldBean(String.format("Hello World, %s", name));
	}

	@GetMapping(path = "/hello-world-internationalized")
	public String helloWorldInternationalized() {
		return messageSource.getMessage("good.morning.message", null, 
									LocaleContextHolder.getLocale());
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/RestfulWebServicesApplication.java

package com.in28minutes.rest.webservices.restfulwebservices;

import java.util.Locale;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver;

@SpringBootApplication
public class RestfulWebServicesApplication {

	public static void main(String[] args) {
		SpringApplication.run(RestfulWebServicesApplication.class, args);
	}
	
	@Bean
	public LocaleResolver localeResolver() {
		AcceptHeaderLocaleResolver localeResolver = new AcceptHeaderLocaleResolver();
		localeResolver.setDefaultLocale(Locale.US);
		return localeResolver;
	}
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/SwaggerConfig.java

package com.in28minutes.rest.webservices.restfulwebservices;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@Configuration
@EnableSwagger2
public class SwaggerConfig {

	public static final Contact DEFAULT_CONTACT = new Contact(
			"Ranga Karanam", "http://www.in28minutes.com", "[email protected]");
	
	public static final ApiInfo DEFAULT_API_INFO = new ApiInfo(
			"Awesome API Title", "Awesome API Description", "1.0",
			"urn:tos", DEFAULT_CONTACT, 
			"Apache 2.0", "http://www.apache.org/licenses/LICENSE-2.0");

	private static final Set<String> DEFAULT_PRODUCES_AND_CONSUMES = 
			new HashSet<String>(Arrays.asList("application/json",
					"application/xml"));

	@Bean
	public Docket api() {
		return new Docket(DocumentationType.SWAGGER_2)
				.apiInfo(DEFAULT_API_INFO)
				.produces(DEFAULT_PRODUCES_AND_CONSUMES)
				.consumes(DEFAULT_PRODUCES_AND_CONSUMES);
	}
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/Post.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

import com.fasterxml.jackson.annotation.JsonIgnore;

@Entity
public class Post {
	
	@Id
	@GeneratedValue
	private Integer id;
	private String description;
	
	@ManyToOne(fetch=FetchType.LAZY)
	@JsonIgnore
	private User user;
	
	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getDescription() {
		return description;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	public User getUser() {
		return user;
	}

	public void setUser(User user) {
		this.user = user;
	}

	@Override
	public String toString() {
		return String.format("Post [id=%s, description=%s]", id, description);
	}
	
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/PostRepository.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface PostRepository extends JpaRepository<Post, Integer>{

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/User.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import java.util.Date;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.validation.constraints.Past;
import javax.validation.constraints.Size;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;

@ApiModel(description="All details about the user.")
@Entity
public class User {

	@Id
	@GeneratedValue
	private Integer id;

	@Size(min=2, message="Name should have atleast 2 characters")
	@ApiModelProperty(notes="Name should have atleast 2 characters")
	private String name;

	@Past
	@ApiModelProperty(notes="Birth date should be in the past")
	private Date birthDate;
	
	@OneToMany(mappedBy="user")
	private List<Post> posts;

	protected User() {

	}

	public User(Integer id, String name, Date birthDate) {
		super();
		this.id = id;
		this.name = name;
		this.birthDate = birthDate;
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Date getBirthDate() {
		return birthDate;
	}

	public void setBirthDate(Date birthDate) {
		this.birthDate = birthDate;
	}

	public List<Post> getPosts() {
		return posts;
	}

	public void setPosts(List<Post> posts) {
		this.posts = posts;
	}

	@Override
	public String toString() {
		return String.format("User [id=%s, name=%s, birthDate=%s]", id, name, birthDate);
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/UserDaoService.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

import org.springframework.stereotype.Component;

@Component
public class UserDaoService {
	
	private static List<User> users = new ArrayList<>();

	private static int usersCount = 3;

	static {
		users.add(new User(1, "Adam", new Date()));
		users.add(new User(2, "Eve", new Date()));
		users.add(new User(3, "Jack", new Date()));
	}

	public List<User> findAll() {
		return users;
	}

	public User save(User user) {
		if (user.getId() == null) {
			user.setId(++usersCount);
		}
		users.add(user);
		return user;
	}

	public User findOne(int id) {
		for (User user : users) {
			if (user.getId() == id) {
				return user;
			}
		}
		return null;
	}

	public User deleteById(int id) {
		Iterator<User> iterator = users.iterator();
		while (iterator.hasNext()) {
			User user = iterator.next();
			if (user.getId() == id) {
				iterator.remove();
				return user;
			}
		}
		return null;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/UserJPAResource.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo;
import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodOn;

import java.net.URI;
import java.util.List;
import java.util.Optional;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.hateoas.Resource;
import org.springframework.hateoas.mvc.ControllerLinkBuilder;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

@RestController
public class UserJPAResource {

	@Autowired
	private UserRepository userRepository;
	
	@Autowired
	private PostRepository postRepository;

	@GetMapping("/jpa/users")
	public List<User> retrieveAllUsers() {
		return userRepository.findAll();
	}

	@GetMapping("/jpa/users/{id}")
	public Resource<User> retrieveUser(@PathVariable int id) {
		Optional<User> user = userRepository.findById(id);

		if (!user.isPresent())
			throw new UserNotFoundException("id-" + id);

		// "all-users", SERVER_PATH + "/users"
		// retrieveAllUsers
		Resource<User> resource = new Resource<User>(user.get());

		ControllerLinkBuilder linkTo = linkTo(methodOn(this.getClass()).retrieveAllUsers());

		resource.add(linkTo.withRel("all-users"));

		// HATEOAS

		return resource;
	}

	@DeleteMapping("/jpa/users/{id}")
	public void deleteUser(@PathVariable int id) {
		userRepository.deleteById(id);
	}

	//
	// input - details of user
	// output - CREATED & Return the created URI

	// HATEOAS

	@PostMapping("/jpa/users")
	public ResponseEntity<Object> createUser(@Valid @RequestBody User user) {
		User savedUser = userRepository.save(user);

		URI location = ServletUriComponentsBuilder.fromCurrentRequest().path("/{id}").buildAndExpand(savedUser.getId())
				.toUri();

		return ResponseEntity.created(location).build();

	}
	
	@GetMapping("/jpa/users/{id}/posts")
	public List<Post> retrieveAllUsers(@PathVariable int id) {
		Optional<User> userOptional = userRepository.findById(id);
		
		if(!userOptional.isPresent()) {
			throw new UserNotFoundException("id-" + id);
		}
		
		return userOptional.get().getPosts();
	}


	@PostMapping("/jpa/users/{id}/posts")
	public ResponseEntity<Object> createPost(@PathVariable int id, @RequestBody Post post) {
		
		Optional<User> userOptional = userRepository.findById(id);
		
		if(!userOptional.isPresent()) {
			throw new UserNotFoundException("id-" + id);
		}

		User user = userOptional.get();
		
		post.setUser(user);
		
		postRepository.save(post);
		
		URI location = ServletUriComponentsBuilder.fromCurrentRequest().path("/{id}").buildAndExpand(post.getId())
				.toUri();

		return ResponseEntity.created(location).build();

	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/UserNotFoundException.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(HttpStatus.NOT_FOUND)
public class UserNotFoundException extends RuntimeException {
	public UserNotFoundException(String message) {
		super(message);
	}
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/UserRepository.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends JpaRepository<User, Integer>{

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/user/UserResource.java

package com.in28minutes.rest.webservices.restfulwebservices.user;

import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo;
import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodOn;

import java.net.URI;
import java.util.List;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.hateoas.Resource;
import org.springframework.hateoas.mvc.ControllerLinkBuilder;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

@RestController
public class UserResource {

	@Autowired
	private UserDaoService service;

	@GetMapping("/users")
	public List<User> retrieveAllUsers() {
		return service.findAll();
	}

	@GetMapping("/users/{id}")
	public Resource<User> retrieveUser(@PathVariable int id) {
		User user = service.findOne(id);
		
		if(user==null)
			throw new UserNotFoundException("id-"+ id);
		
		
		//"all-users", SERVER_PATH + "/users"
		//retrieveAllUsers
		Resource<User> resource = new Resource<User>(user);
		
		ControllerLinkBuilder linkTo = 
				linkTo(methodOn(this.getClass()).retrieveAllUsers());
		
		resource.add(linkTo.withRel("all-users"));
		
		//HATEOAS
		
		return resource;
	}

	@DeleteMapping("/users/{id}")
	public void deleteUser(@PathVariable int id) {
		User user = service.deleteById(id);
		
		if(user==null)
			throw new UserNotFoundException("id-"+ id);		
	}

	//
	// input - details of user
	// output - CREATED & Return the created URI
	
	//HATEOAS
	
	@PostMapping("/users")
	public ResponseEntity<Object> createUser(@Valid @RequestBody User user) {
		User savedUser = service.save(user);
		// CREATED
		// /user/{id}     savedUser.getId()
		
		URI location = ServletUriComponentsBuilder
			.fromCurrentRequest()
			.path("/{id}")
			.buildAndExpand(savedUser.getId()).toUri();
		
		return ResponseEntity.created(location).build();
		
	}
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/versioning/Name.java

package com.in28minutes.rest.webservices.restfulwebservices.versioning;

public class Name {
	private String firstName;
	private String lastName;

	public Name() {
	}

	public Name(String firstName, String lastName) {
		super();
		this.firstName = firstName;
		this.lastName = lastName;
	}

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/versioning/PersonV1.java

package com.in28minutes.rest.webservices.restfulwebservices.versioning;

public class PersonV1 {
	private String name;

	public PersonV1() {
		super();
	}
	
	public PersonV1(String name) {
		super();
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	
}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/versioning/PersonV2.java

package com.in28minutes.rest.webservices.restfulwebservices.versioning;

public class PersonV2 {
	private Name name;

	public PersonV2() {
		super();
	}

	public PersonV2(Name name) {
		super();
		this.name = name;
	}

	public Name getName() {
		return name;
	}

	public void setName(Name name) {
		this.name = name;
	}

}

---

/src/main/java/com/in28minutes/rest/webservices/restfulwebservices/versioning/PersonVersioningController.java

package com.in28minutes.rest.webservices.restfulwebservices.versioning;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class PersonVersioningController {

	@GetMapping("v1/person")
	public PersonV1 personV1() {
		return new PersonV1("Bob Charlie");
	}

	@GetMapping("v2/person")
	public PersonV2 personV2() {
		return new PersonV2(new Name("Bob", "Charlie"));
	}

	@GetMapping(value = "/person/param", params = "version=1")
	public PersonV1 paramV1() {
		return new PersonV1("Bob Charlie");
	}

	@GetMapping(value = "/person/param", params = "version=2")
	public PersonV2 paramV2() {
		return new PersonV2(new Name("Bob", "Charlie"));
	}

	@GetMapping(value = "/person/header", headers = "X-API-VERSION=1")
	public PersonV1 headerV1() {
		return new PersonV1("Bob Charlie");
	}

	@GetMapping(value = "/person/header", headers = "X-API-VERSION=2")
	public PersonV2 headerV2() {
		return new PersonV2(new Name("Bob", "Charlie"));
	}

	@GetMapping(value = "/person/produces", produces = "application/vnd.company.app-v1+json")
	public PersonV1 producesV1() {
		return new PersonV1("Bob Charlie");
	}

	@GetMapping(value = "/person/produces", produces = "application/vnd.company.app-v2+json")
	public PersonV2 producesV2() {
		return new PersonV2(new Name("Bob", "Charlie"));
	}

}

---

/src/main/resources/application.properties

logging.level.org.springframework = info
#This is not really needed as this is the default after 2.0.0.RELEASE
spring.jackson.serialization.write-dates-as-timestamps=false
spring.messages.basename=messages
management.endpoints.web.exposure.include=*
spring.security.user.name=username
spring.security.user.password=password
spring.jpa.show-sql=true
spring.h2.console.enabled=true

---

/src/main/resources/data.sql

insert into user values(10001, sysdate(), 'AB');
insert into user values(10002, sysdate(), 'Jill');
insert into user values(10003, sysdate(), 'Jam');
insert into post values(11001, 'My First Post', 10001);
insert into post values(11002, 'My Second Post', 10001);

---

/src/main/resources/messages.properties

good.morning.message=Good Morning

---

/src/main/resources/messages_fr.properties

good.morning.message=Bonjour

---

/src/main/resources/messages_nl.properties

good.morning.message=Goede Morgen

---

/src/test/java/com/in28minutes/rest/webservices/restfulwebservices/RestfulWebServicesApplicationTests.java

package com.in28minutes.rest.webservices.restfulwebservices;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class RestfulWebServicesApplicationTests {

	@Test
	public void contextLoads() {
	}

}

---