Spring and Rest

REST capability is built in to Spring MVC

➤use domain objects as parameters/return values
➤mark with @RequestBody/@ResponseBody
➤Spring MVC automatically handles XML/JSON Conversion
Based on converters available in class path

Demonstrate REST Controllers in Spring MVC
 - Additional domain objects
 - Automatic HTTP Message Conversion

changes in model class
create classes-

1- Team
package com.domain;

import java.util.Set;

public class Team {
  String name;
  String location;
  String id;
  Set<Player> players;
  
public Team(String name, String location, String id, Set<Player> players) {
super();
this.name = name;
this.location = location;
this.id = id;
this.players = players;
}
public Set<Player> getPlayers() {
return players;
}
public void setPlayers(Set<Player> players) {
this.players = players;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
  

}

2- Player

package com.domain;

public class Player {

   public Player(String name, String position) {

super();

this.name = name;

this.position = position;

}

String name;

   String position;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getPosition() {

return position;

}

public void setPosition(String position) {

this.position = position;

}

   

}

Controller

                               InitialController

package com.demo;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

import javax.annotation.PostConstruct;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.ResponseBody;

import com.domain.Player;

import com.domain.Team;

@Controller

public class InitialController {

    

private Team team;

@PostConstruct

public void init() {

Set<Player> players = new HashSet<>();

players.add(new Player("player1","A"));

players.add(new Player("player2","B"));

players.add(new Player("player3","C"));

team= new Team("xyz","India","p",players);

}

@RequestMapping("/hi")

public @ResponseBody Team helloWorld(Map model) {

return team;

}

 

}

DemoApplication

package com.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.builder.SpringApplicationBuilder;

import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication

public class DemoApplication extends SpringBootServletInitializer{

public static void main(String[] args) {

SpringApplication.run(DemoApplication.class, args);

}

@Override

protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {

return application.sources(DemoApplication.class);

}

}

response-

http://localhost:8080/hi/

{

"name": "xyz",

"location": "India",

"id": "p",

"players": [{

"name": "player3",

"position": "C"

}, {

"name": "player1",

"position": "A"

}, {

"name": "player2",

"position": "B"

}

]

}

Description    ::::::::

➤Controller returned a domain object

 NOT a logical view name(page)

➤Spring MVC noticed @ResponseBody

- or @RestController

➤ invoked correct HttpMesageConverter

-Based on

•   Requested format
•   JARS on classpath

what if i want XML 

➤Annotate domain class with JAXB annotation

JAXB already part of java SE

➤when app starts

Spring creates HttpMessageConverter for JAXB

• based on classpath contents 

➤XML or JSON returned

based on requested format

@XmlRootElement
public class Team {
.....

}

http://localhost:8080/hi/

Adding JPA capabilities

https://javacmlearning.blogspot.com/2019/09/spring-boot-adding-jpa-capability.html