REST.txt

1.  REST client demo


Create a spring mvc application.

asual define config and controller is now replaced to REST controller

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2. already we created back end services with jar.

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3. REST clien we need to incorp.


create lib folder

web-inf/lib

Add h2 and backendservices jar

and build the path

or

Maven dependency to add the jar

   <dependency>
   <groupId>com.niit</groupId>
  <artifactId>ItemBackend</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  </dependency>
  	



------------------

4.

<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>5.0.5.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>5.0.5.RELEASE</version>
		</dependency>
		
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-databind</artifactId>
			<version>2.9.5</version>
		</dependency>
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-entitymanager</artifactId>
			<version>5.2.16.Final</version>
		</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1.0</version>
    <scope>provided</scope>
</dependency>

		<!-- https://mvnrepository.com/artifact/jstl/jstl -->
<dependency>
    <groupId>jstl</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
</dependency>
		
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-dbcp2</artifactId>
			<version>2.2.0</version>
		</dependency>

<dependency>
   <groupId>com.h2database</groupId>
   <artifactId>h2</artifactId>
   <version>1.4.196</version>
   <scope>test</scope>
</dependency>
  
  
  
  <dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>5.0.5.RELEASE</version>
		</dependency>
  	<dependency>
    <groupId>com.niit</groupId>
  <artifactId>ItemBackend</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  </dependency>
  	

		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>5.0.5.RELEASE</version>
		</dependency>
    
    <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.5</version>
    </dependency>

--------------------------------------------
5.


package com.niit.ItemRest.config;


import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages="com.niit")
public class AppConfig {
	
	@Bean(name="viewResolver")
	public ViewResolver getViewResolver() {
		InternalResourceViewResolver viewResolver=new InternalResourceViewResolver();
		viewResolver.setPrefix("/WEB-INF/views/");
		viewResolver.setSuffix(".jsp");
		
		
		return viewResolver;
		
	}


}

----------------------------------------------------------------

6.

package com.niit.ItemRest.config;


import javax.servlet.ServletRegistration;

import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;


public class WebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

	@Override
	protected Class<?>[] getRootConfigClasses() {
		// TODO Auto-generated method stub
	//	return null;
		return new Class[] {AppConfig.class};
	}

	@Override
	protected Class<?>[] getServletConfigClasses() {
		// TODO Auto-generated method stub
		return null;
	}

	public void addCorsMappings(CorsRegistry registry) {
        

		registry.addMapping("/**");
		    }

	@Override
	protected String[] getServletMappings() {
		// TODO Auto-generated method stub
		//return null;
		return new String[] {"/"};
	}

	
	@Override
	protected void customizeRegistration(ServletRegistration.Dynamic registration)
	{
		registration.setInitParameter("dispatchOptionsRequest","true");
		registration.setAsyncSupported(true);
	}
}
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7.  // REST is not focused on UI


put by default 


index.jsp
<html>
<body>
<h2>Hello World!</h2>
</body>
</html>


---------------------------------------------------
package com.niit.ItemRest.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import com.niit.ItemBackend.model.*;
import com.niit.ItemBackend.service.ItemService;


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

@RestController
@RequestMapping("/api/item")
@CrossOrigin(origins = "http://localhost:4200")
public class ItemController {


	@Autowired
	private ItemService itemService; // DI
	
	
	
	@GetMapping
	public List<Item> listAllItem() {
		
		  List<Item> item=itemService.findAllItems();//
		//, HttpStatus.CREATED);
		  return item;
	}
	
	@GetMapping("/{itemId}")
	public ResponseEntity<Item> getItem(@PathVariable("itemId") int itemId) {
		
		if(itemService.findItemById(itemId)!=null) {
			return new ResponseEntity<Item>(itemService.findItemById(itemId),                                  HttpStatus.OK);
		}
		else 
			return new ResponseEntity<Item>(HttpStatus.NOT_FOUND); 
	}
	
	
	
	@DeleteMapping("/{itemId}")
	public ResponseEntity<Void> deleteItem(@PathVariable("itemId") int itemId) {
		
		if(itemService.findItemById(itemId)!=null) {
			itemService.deleteItem(itemId);
			return new ResponseEntity<Void>(HttpStatus.OK);
		}
		else 
			return new ResponseEntity<Void>(HttpStatus.NOT_FOUND); 
	}
	
	@PostMapping
	public ResponseEntity<Void> addItem(@RequestBody Item item) {
		
		if(itemService.findItemByName(item.getDescription())!=null) {
			
			return new ResponseEntity<Void>(HttpStatus.CONFLICT);
		}
		else {
			itemService.addItem(item);
			return new ResponseEntity<Void>(HttpStatus.CREATED);
		}
	}
	
	@PutMapping
	public ResponseEntity<Void> updateItem(@RequestBody Item item) {
		
		if(itemService.findItemById(item.getItemId())!=null) {
			itemService.updateItem(item);
			return new ResponseEntity<Void>(HttpStatus.OK);
		}
		else {
			
			return new ResponseEntity<Void>(HttpStatus.NOT_FOUND);
		}
	}
	
	
	
}
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