Spring boot and Spring Data JPA

1. Create an entity class bean

 PackageCom.example.bean;ImportJavax.persistence.*; @Table (name= "Grade") @Entity Public classGrade {@Id @GeneratedValue (strategy= Generationtype.auto)//ID and Generatedvalue must be used simultaneously    Private intID; PrivateString Gradenm; Private intTeacherid; @Override PublicString toString () {return"grade{" + "id=" + ID + ", gradenm=" + gradenm + "\" + ", teacherid=" + Tea Cherid + '} '; }     Public intgetId () {returnID; }     Public voidSetId (intID) { This. ID =ID; }     PublicString Getgradenm () {returnGradenm; }     Public voidsetgradenm (String gradenm) { This. Gradenm =Gradenm; }     Public intGetteacherid () {returnTeacherid; }     Public voidSetteacherid (intTeacherid) {         This. Teacherid =Teacherid; }}

2. Create Repository

1) crudrepository

 Packagecom.example.reposittory;ImportCom.example.bean.Grade;ImportOrg.springframework.data.jpa.repository.Query;Importorg.springframework.data.repository.CrudRepository;ImportOrg.springframework.data.repository.query.Param; Public InterfaceGradecrudrepositoryextendsCrudrepository<grade,integer> {     PublicGrade findbygradenm (String gradenm); @Query (Value= "from Grade b where gradenm=:nm")     PublicGrade Findmygrade (@Param ("NM") String gradenm); }

2) Repository

 Packagecom.example.reposittory;ImportCom.example.bean.Grade;ImportOrg.springframework.data.jpa.repository.Query;Importorg.springframework.data.repository.Repository;ImportOrg.springframework.data.repository.query.Param; Public InterfaceGraderepositoryextendsRepository<grade,integer> {     PublicGrade findbygradenm (String gradenm); @Query (Value= "from Grade b where gradenm=:nm")     PublicGrade Findmygrade (@Param ("NM") String gradenm);}

3) Pagingandsortingrepository

 Packagecom.example.reposittory;ImportCom.example.bean.Grade;ImportOrg.springframework.data.jpa.repository.Query;Importorg.springframework.data.repository.CrudRepository;Importorg.springframework.data.repository.PagingAndSortingRepository;ImportOrg.springframework.data.repository.query.Param; Public InterfaceGradepageandsortrepositoryextendsPagingandsortingrepository<grade,integer>{Grade findbygradenm (String gradenm); @Query (Value= "from Grade b where gradenm=:nm") Grade Findmygrade (@Param ("NM") String gradenm); }

3. Create service

 PackageCom.example.service;ImportCom.example.bean.Grade;Importcom.example.reposittory.GradeRepository;Importcom.example.reposittory.GradeCrudRepository;Importorg.springframework.data.domain.PageRequest;Importorg.springframework.data.repository.PagingAndSortingRepository;ImportOrg.springframework.stereotype.Service;ImportJavax.annotation.Resource;Importjavax.transaction.Transactional; @Service Public classGradeservice {@ResourcePrivategraderepository graderepository; @ResourcePrivategradecrudrepository GradeRepository2; @ResourcePrivatepagingandsortingrepository GradeRepository3;  PublicGrade findbygradenm (String gradenm) {Grade bygradenm=Graderepository.findbygradenm (GRADENM); returnBygradenm; }     PublicGrade Findmygrade (String gradenm) {Grade bygradenm=Graderepository.findmygrade (GRADENM); returnBygradenm; } @Transactional Public  voidSave (Grade Grade) {graderepository2.save (Grade); } @Transactional Public  voidDeleteintID)    {graderepository2.delete (ID); }     PublicIterable<grade>GetAll () {returnGraderepository3.findall (NewPagerequest (0,3)); }}

4. Create control

 PackageCom.example.controller;ImportCom.example.bean.Grade;ImportCom.example.service.GradeService;Importorg.springframework.web.bind.annotation.*;ImportJavax.annotation.Resource;Importjava.util.ArrayList;ImportJava.util.Iterator;Importjava.util.List; @RestController Public classGradecontroller {@ResourcePrivateGradeservice Gradeservice; @RequestMapping ("/findbygradenm")     PublicGrade findbygradenm (String gradenm) {Grade bygradenm=Gradeservice.findbygradenm (GRADENM); returnBygradenm; } @RequestMapping ("/findmygradenm")     PublicGrade Findmygrade (String gradenm) {Grade bygradenm=Gradeservice.findmygrade (GRADENM); returnBygradenm; } @RequestMapping ("/save")     PublicString Save (@RequestParam ("Gradenm") string gradenm, @RequestParam ("id")intID) {Grade Grade=NewGrade ();        Grade.setgradenm (GRADENM);        Grade.setteacherid (ID);        Gradeservice.save (grade); return"Success"; } @RequestMapping ("/delete")     PublicString Delete (intID) {gradeservice.delete (ID); return"Success"; } @RequestMapping (Value= "/getall", method =requestmethod.get) Public@ResponseBody list<grade>GetAll () {iterable<Grade> all =Gradeservice.getall (); Iterator<Grade> iterator =All.iterator (); List<Grade> grades =NewArraylist<>();  while(Iterator.hasnext ()) {Grade Grade=Iterator.next ();        Grades.add (grade); }        returngrades; }}

5. Spring Boot entry

 Package com.example; Import org.springframework.boot.SpringApplication; Import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication  Public class hctspringbootapplication {    publicstaticvoid  main (string[] args ) {        Springapplication.run (hctspringbootapplication. class , args);}    }

6. Testing

1) Check All

2) Save data

Spring boot and Spring Data JPA