how to create rest api using spring boot in eclipse

 how to create rest api using spring boot in eclipse

For Explanation Watch Video:

Directory:

application.properties::

#server port

server.port=3031

#datasource

spring.datasource.url=jdbc:mysql://localhost:3306/new

spring.datasource.username=root

spring.datasource.password=root

#jpa

spring.jpa.show-sql=true

spring.jpa.hibernate.ddl-auto=create

SpringBootRestApplication 

package com.app;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

public class SpringBootRestApplication {

public static void main(String[] args) {

SpringApplication.run(SpringBootRestApplication.class, args);

}

}

StudentController 

package com.app.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.web.bind.annotation.DeleteMapping;

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

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

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.RequestMapping;

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

import com.app.entity.Student;

import com.app.service.IStudentService;

@RestController

@RequestMapping("/student")

public class StudentController {

@Autowired

private IStudentService service;

//1.save student

@PostMapping("/save")

public ResponseEntity<String> saveStudent(@RequestBody Student std){

ResponseEntity<String> response = null;

//call the service 

Integer id = service.saveStudent(std);

String msg  = "Student with id '"+id+"' is saved";

response = new ResponseEntity<String>(msg,HttpStatus.OK);

return response;

}

//2.get all student

@GetMapping("/all")

public ResponseEntity<List<Student>> getAll(){

ResponseEntity<List<Student>> response = null;

//call the service

List<Student> list = service.getAllStudents();

response = new ResponseEntity<List<Student>>(list,HttpStatus.OK);

return response;

}

//3.get One student

@GetMapping("/get/{sid}")

public ResponseEntity<Student> getOneStudent(@PathVariable Integer sid){

ResponseEntity<Student> response = null;

//call the service

Student std = service.getStudentById(sid);

response = new ResponseEntity<Student>(std,HttpStatus.OK);

return response;

}

//4.update student

@PutMapping("/update")

public ResponseEntity<String> updateStudent(@RequestBody Student std){

ResponseEntity<String> response = null;

//call the service

service.updateStudent(std);

String msg = "Student Updated";

response = new ResponseEntity<String>(msg,HttpStatus.OK);

return response;

}

//5.delete student by id

@DeleteMapping("/delete/{sid}")

public ResponseEntity<String> deleteOneStudent(@PathVariable Integer sid){

ResponseEntity<String> response = null;

//call the service

service.deleteStudentById(sid);

String msg = "Student Deleted";

response = new ResponseEntity<String>(msg,HttpStatus.OK);

return response;

}

//6.partial update

@PatchMapping("/modify/{sid}/{add}")

public ResponseEntity<String> updateStudentAddress(

@PathVariable Integer sid

,@PathVariable String add){

ResponseEntity<String> response = null;

//call the service

service.updateStudentAdd(sid, add);

String msg = "Student address with id '"+sid+"' updated";

response = new ResponseEntity<String>(msg,HttpStatus.OK);

return response;

}

}

Student 

package com.app.entity;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;

import lombok.AllArgsConstructor;

import lombok.Data;

import lombok.NoArgsConstructor;

@Data

@AllArgsConstructor

@NoArgsConstructor

@Entity

@Table(name = "stutab")

public class Student {

@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

@Column(name = "sid")

private Integer studentId;

@Column(name = "sname")

private String studentName;

@Column(name = "sadd")

private String studentAddresss;

@Column(name = "avg")

private Double studentAvg;

}

StudentRepository 

package com.app.repo;

import org.springframework.data.jpa.repository.JpaRepository;

import org.springframework.data.jpa.repository.Modifying;

import org.springframework.data.jpa.repository.Query;

import com.app.entity.Student;

public interface StudentRepository extends JpaRepository<Student, Integer>{

@Modifying//non-select

@Query("UPDATE Student SET studentAddresss=:add WHERE studentId=:id")

Integer updateStudentAddById(Integer id,String add);

}

IStudentService 

package com.app.service;

import java.util.List;

import com.app.entity.Student;

public interface IStudentService {

//1.save student

Integer saveStudent(Student std);

//2.get all student

List<Student> getAllStudents();

//3.get student by id

Student getStudentById(Integer id);

//4.delete student by id

void deleteStudentById(Integer id);

//5.update

void updateStudent(Student std);

//6.partial update

Integer updateStudentAdd(Integer sid,String add);

}

StudentServiceImpl 

package com.app.service.impl;

import java.util.List;

import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.transaction.annotation.Transactional;

import com.app.entity.Student;

import com.app.repo.StudentRepository;

import com.app.service.IStudentService;

@Service

public class StudentServiceImpl implements IStudentService{

@Autowired

private StudentRepository repo;

@Override

public Integer saveStudent(Student std) {

std = repo.save(std);

return std.getStudentId();

}

@Override

public List<Student> getAllStudents() {

return repo.findAll();

}

@Override

public Student getStudentById(Integer id) {

Optional<Student> opt = repo.findById(id);

if(opt.isEmpty()) {

return null;

}

return opt.get();

}

@Override

public void deleteStudentById(Integer id) {

repo.deleteById(id);

}

@Override

public void updateStudent(Student std) {

repo.save(std);

}

@Transactional

public Integer updateStudentAdd(Integer sid, String add) {

// TODO Auto-generated method stub

return repo.updateStudentAddById(sid, add);

}

}