[Java Web Application] JPA Shop

Reference by 실전! 스프링 부트와 JPA 활용 1 - 웹 애플리케이션 개발

Settings

• Create project
  • Spring boot starter
  • dependencies : web, thymeleaf, jpa, h2, lombok, validation, devtools

  

• Download lombok plugin

• build.gradle
  • Add spring-boot-devtools(for recompile)
  • Add P6Spy
• h2 database
  • Download
  • Go to h2/bin and excute h2-1.4.200.jar(os : window)
  • Connect DB

  

• Domain

  

  • Connect DB

  

  • @ManyToOne, @OneToMany
    Don’t use @ManyToMany. It cannot add colums in middle table.
    So create middle entity and mapping with @ManyToOne and @OneToMany.
• Download Bootstrap

View

• Thymeleaf Template Engine
  • Spring Boot thymeleaf View Name
    (resources:templates/) + {ViewName} + (.html)

    @Controller
    public class HelloController{

      @GetMapping("hello)
      public String hello(Model model){
        model.addAttribute("data", "hello!!");
        return "hello";
      }
    }
  

• Template location
  resource/templates/hello.html
• Skip null when use ?

Entity

• fetch = FetchType.LAZY
  • EAGER is hard to expect and follow which SQL will excute.
  • To check related entities in DB together, use fetch, join or Entity Graph Function.
  • Need to set fetch = FetchType.LAZY in @OneToOne, @ManyToOne.

Application Architecture

• Hierarchy Structure
  • controller, web: web level
  • service: business logic, transaction process
  • repository: use JPA directly, use entity manager
  • domain: gather entities

Member

Repository

• @Repository: Register as a spring bin
• @PersistenceContext: Insert EntityManager
• @PersistenceUnit: Insert EntityManagerFactory

Service

• @Transactional: Transaction, perpetuity context
  • readOnly=true: Use for read-only methods
• @Autowired: Use for many Generator Injection
  • If there is only one Generator, it can be skipped
• final: Use to check error unsetted ~Repository

Test

• @RunWith(SpringRunner.class): Combinate Spring and test
• @SpringBootTest: Excute Spring Boot first, then test
• @Transactional: Support repeatable test
  • Rollback after the test
• //Given, //When, //Then
• Setting for Test Case
  • Run in isolated environment and initialize data at end
  • Use Memory DB
  • Add Setting file for Test test/resources/application.yml

    spring:
    logging.level:
      org.hibernate.SQL: debug
  

Item

Entity

• addStock(): Increase stock quantity when modify wtock quantity or cancel order
• removeStock(): Decrease stock quantity. When stock is lack, generate error.

Repository

• save()
  • Execute persist() for new id
  • Excutee merge() for existed id

Order

Entity

• createdOrder(): Create Order Entity
• cancle(): Change order status to cancle

Repository

• findAll(OrderSearch orderSearch): Create queries dynamically in search condition to check order entities

Service

• order(): Create Order Entity
• cancleOrder(): Request cancel to Order
• findOrders(): Search Order Entity with OrderSearch condition

  Domain Model Pattern: Entity has business logic
  Transaction Script Pattern: Service has business logic

Test

• Generate NotEnoughStockException when order exceeds stock quantity

OrderItem

Entity

• createOrderItem(): Create OrderItem Entity and call item.removeStock(count) to decrease stock quantity as much as order
• cancle(): Call getItem().addStock(count) to increase stock quantity as much as cancled order
• getTotalPrice(): Return count * price

Controller

• Save Model object to send View
• Press Submit, then request url with POST method
  • After the change, redirect redirect:/~
  • Excute method
• Press Modify, then request url with GET method
  • Execute updateItemForm() method and call itemService.findOne(itemId)
  • send result to View
• Always use change detection when changing an entity.

UI

• Main

  

• Member

  

• Product

  

• Order

  

Demo Video

• Member
  
• Product
  
• Modify
  
• Order
  
• Cancle
  
• Search orders
  

Download