Spring Boot Part-2

 

Note:
Understand the current blog(Spring Boot-2). Please walk through the previous blog-Spring Boot-1

Implement the update the delete operations in Spring Boot

Add a update method in service

 

Write the delete the service

a)   Write a delete method in the controller

Write delete method in the service class

 

 

Spring Data JPA: The Data Tire

Java Persistence API - specification of ORM. Object - Releational Mapping - SQL db (Relational DB) Entity class map to table. You don't need to query in the db.  Spring Data JPA - working with ORM tool. To connect to db. 

 

Create a new Project for SPRING JPA

New Spring Starter Project in STS
Name: course-api-data
Type: Maven Project

Java version: 1.8
Package: Jar
Language:Java
Group: io.javabrains
artifact:course-api-data
Description: Coursse API WITH data for Spring Boot Quick start
Package:io.javabrains

Click NextSelect the Dependencies

Web -> Web

SQL -> JPA (SPRING JPA),  Apache Derby (embedded db)

Click Next – Finish

 

Add a Boot class

 

 

 

Creating a Spring Data JPA Repository

 

a) Model needs to implement the JPA

@Entity - Define in Class level. This will create a table.

@Entity

public class Topic 

b) Define the primary key

@Id

private String id;

Service talks to Data Repository

Create TopicRepository interface. Framework will take care the CRUD operations by CrudRepository interface.
//getAllTopics()
//getTopic(String id)
//addTopic(Topic t)
//updateTopic(Topic t, String id)
//deleteTopic(String id)

 

public interface TopicRepository extends CrudRepository <Topic, String>{ 
}

 

 

 

 

 

 

 

Making CRUD Operations.

Change in the Service class

a) Declare the TopicRepoistory and add AutoWired

b) service method call the repoistory method

 

public List<Topic> getAllTopics(){

 List<Topic> topic = new ArrayList<>();
 topicRepoistory.findAll().forEach(topic::add);
 return topics;
}

public void addTopic(Topic topic){

 topicRepository.save(topic);
}

public Topic getTopic(String id){

 topicRepository.findOne(id);
}

public void updateTopic(String id, Topic topic){

 topicRepository.save(topic);  //used for update or insert
}

public Topic deleteTopic(String id){

 topicRepository.delete(id);
}

 

 

 

Created the Repository

 

Add the jpa and db dependencies in the pom.xml file

Marked the entity class as @Entity and primary column as @Id in the member variable.
Implemented the Repository interface which extends CrudRepoistory<Topic, String>
Add the service which talk to Data Repository

 

Adding Course APICopy the Topic package to new package called "course"

Rename Class Topic to course for Model, controller, repoistory, service
Link course and Topic by adding member topic in Course class

 

 

 

 

Adding Entity Relationship and extending repositoryCustom Method in Crud Repository
CrudRepository custom methods.
findBy<element>
findByName(String name)
findByDescription(String description)
findBy<Object><Member>(parameter id)
findByTopicId(String topic id);

 

 

Packaging and running a Spring Boot app

Built jar file and run
compile and generate the jar file
 mvn clean install

clean project , download necessary dependencies , compile and do the unit test and create a jar file and make that available in the project folder.

Project Name\target\project.xxxx.jar

java -jar target/project.jar

Spring Boot Actuator

Production ready feature to help you monitor and manage you application.

spring-boot-starter-actuator add dependency in the pom.xml

http://localhost:8080/health

 

 

Source from https://www.javabrains.io