Setup Workspace Create new starter project Add spring web, Lombok, Spring data jpa, mysql driver Optional on error - to forcing the build https://stackoverflow.com/questions/6021899/eclipse-maven-multiple-annotations-found-at-this-line/18800625 Optional on JRE - select project=> option(right click)=> configure build path => Library => set jdk to one that you selected at project initialization Configure mysql db Open application.properties file and add datasource and hibernate dialect properties spring.datasource.url=jdbc:mysql://localhost:3306/ems?useSSL=false spring.datasource.username=root spring.datasource.password=root Hibernate properties spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect Create, create-drop spring.jpa.hibernate.ddl-auto=update Jdbc driver Jdbc url Jdbc username Jdbc paw Create package structure for your workspace Controller Exception Model Repository Service Service.impl Optional - Remember Controllers created outside the main package won’t work. So create all packages inside your main package e.g. (com.test.Main) Run query on MySQL Workbench create database ems; Refresh and check the db is created in ems or not Configure in spring boot project in application.properties and add /ems in datasource.url Configure mysql db Open application.properties file and add datasource and hibernate dialect properties spring.datasource.url=jdbc:mysql://localhost:3306/ems?useSSL=false spring.datasource.username=root spring.datasource.password=root@1234 #Hibernate properties spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect #Create, create-drop spring.jpa.hibernate.ddl-auto=update Jdbc driver Jdbc url Jdbc username Jdbc paw Now run your project and check everything work fine - Successfully setup
Create JPA Entity
Create a model named Employee.java @Data - lombok => Add lombok class notation with a class that will create a Getter Setter automatically. Or create source from constructors, getter and setters short key 1, lombok reduce boilerplate code like getter, setter, constructor, toString ... @Entity - javax.persistence - from persistence class that specify that class is an entity, jpa entity @Table - javax.persistence - this annotation have property name that will define the table name, if not then it will automatically take the class name Id Use @Id to create primary key Use @GenerateValue(strategy = GenerationType.IDENTITY) to mek it auto generated id of long type. Lets define Firstname - now add column details for other fieldss @Column(name= “first_name”, nullable = false) Do this for other type as well @Column(name= “email”) @Column(name= “last_name”) Hibernate will create these properties automatically. Let’s run and see if the table is created in MySql or not. Open workbench tap on home and tap on your sql workspace Done - we have successful created our employee jpa entity
package com.poc.springboot.Model;
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table;
@Entity @Table(name="employee") public class Employee{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
@Column(name="first_name", nullable = false)
private String firstName;
@Column(name="last_name")
private String lastName;
@Column(name="email")
private String email;
public Employee() {
super();
}
public Employee(long id, String firstName, String lastName, String email) {
super();
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
this.email = email;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
Create Repository Name the interface EmoployeeRepository extends JPARepository<Employee, Long> Theory - Reqpo is responsible to our CRUD operations This is a interface extends to our JPARepository Spring Data JPA internally provides @Repository annotation so we don’t need to add @repository annotation to Employee Repository interface @transactional is also defined in jap repo
Create Exception Create Exception class in Exception package name it ResourceNotFoundException that extends RuntimeException Resource not found exception extends RuntimeException Add annotation @ExceptionStatus(value = HttpStatus.NOT_FOUND) private static final long serialVersionUID = 1L; Add property private String resourceName,fieldName, Object fieldValue; Generate constructors for all the fields and add default message with format super(String.format(“%s not found with %s : ‘%s’”,resourceName, fieldName, fieldValue)); Generate getters Done
package com.poc.springboot.Exception;
import org.springframework.http.HttpStatus; import org.springframework.web.bind.annotation.ResponseStatus;
@ResponseStatus(value = HttpStatus.NOT_FOUND) public class ResourceNotFoundException extends RuntimeException{
private static final long serialVersionUID = 1L;
private String resourceName,fieldName;
private Object fieldValue;
public ResourceNotFoundException(String resourceName, String fieldName, Object fieldValue) {
super(String.format("%s not found with %s : '%s'", resourceName, fieldName, fieldValue));
this.resourceName = resourceName;
this.fieldName = fieldName;
this.fieldValue = fieldValue;
}
public String getResourceName() {
return resourceName;
}
public void setResourceName(String resourceName) {
this.resourceName = resourceName;
}
public String getFieldName() {
return fieldName;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}
public Object getFieldValue() {
return fieldValue;
}
public void setFieldValue(Object fieldValue) {
this.fieldValue = fieldValue;
}
}
Create Service Create new interface in Service package name EmployeeService - don’t forget to change package from com.poc.springboot.Service.impl to com.poc.springboot.Service Create new class in Service.impl package name EmployeeServiceImpl EmployeeServiceImpl Implement EmployeeService @Service annotation EmployeeServiceImpl Define a method in interface EmployeeService - Employee saveEmployee(Employee employee); Implement the method in class EmployeeServiceImpl Theory In Employee impl - There are two type of dependency injection
- Setter based dependency injection
- Constructor based dependency injection We will use constructor base constructor based dependency Spring 4.3 if a class configured as a spring bean has only one constructor, @autowired can be omitted and spring will use that constructor and inject all necessary dependency Add auto generated method stub in impl file Create private EmployeeRepository employeeRepository; Create its constructor Call save method from repository in override method and return Employee.
Create Controller
Create class EmployeeController in controller package Add @RestController annotation Theory RestController is a convenient annotation that combines @controller and @ResponseBody, which eliminates the need to annotation every request handling method of the controller class with the @Response/body annotation. Create property for service - private EmployeeService employeeService; Create constructor Create endpoint method that will hold request and response paths - saveEmployee Use return type as ResponseEntity - to add status and header automatically Add @postmaping and @RequestBody to this @postMapping public ResponseEntity saveEmployee(@RequestBody Employee employee) { return new object of ResponseEntity have two param service.save(employee), code as CREATED}
package com.poc.springboot.Controller;
import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RestController;
import com.poc.springboot.Model.Employee; import com.poc.springboot.Service.EmployeeService;
@RestController public class EmployeeController { private EmployeeService employeeService;
public EmployeeController(EmployeeService employeeService) {
super();
this.employeeService = employeeService;
}
@PostMapping("/save")
public ResponseEntity<Employee> saveEmployee(Employee employee){
return new ResponseEntity<Employee>(employeeService.saveEmployee(employee), HttpStatus.CREATED);
}
}
PostMan Testing url http://localhost:8080/api/mobile/employee/test
http://localhost:8080/api/mobile/employee/save
Create api post type body raw type and JSON Create body { "fristName":"akash", "lastName":"soni", "email":"[email protected]" }
Hit api And hit
{ "timestamp": "2021-11-28T07:46:58.485+00:00", "status": 404, "error": "Not Found", "path": "/api/mobile/employee/save" }
Further API creation Step Create Service
Create service impl
Goto controller add method and path
Done
Get employee by id example
Create Service Employee findById(long id);
Create service impl @Override public Employee findById(long id) { // TODO Auto-generated method stub /* Optional employee = employeeRepository.findById(id); if (employee.isPresent()){ return employee.get(); }else { throw new ResourceNotFoundException("Employee", "Id", employee); } * */
// or use lambda function
return employeeRepository.findById(id).orElseThrow( () -> new ResourceNotFoundException("Employee", "Id", id));
}
Goto controller add method and path @GetMapping("{id}") public ResponseEntity getEmployeeById(@PathVariable("id") long id){ return new ResponseEntity(employeeService.findById(id), HttpStatus.OK); }
Done Update Employee by id
Employee updateEmployeeById(Employee employee, long id);
@Override
public Employee updateEmployeeById(Employee employee, long id) {
// TODO Auto-generated method stub
Employee existingEmployee = employeeRepository.findById(id).orElseThrow( () -> new ResourceNotFoundException("Employee", "Id", id));
existingEmployee.setFirstName(employee.getFirstName());
existingEmployee.setLastName(employee.getLastName());
existingEmployee.setEmail(employee.getEmail());
employeeRepository.save(existingEmployee);
return existingEmployee;
}
@PutMapping("{id}")
public ResponseEntity<Employee> updateEmployeeById(@RequestBody Employee employee, @PathVariable("id") long id){
return new ResponseEntity<Employee>(employeeService.updateEmployeeById(employee,id), HttpStatus.OK);
}
Delete Employee by id Employee deleteEmployeeById(long id);
@Override
public Employee deleteEmployeeById(long id) {
// TODO Auto-generated method stub
Employee existingEmployee = employeeRepository.findById(id).orElseThrow( () -> new ResourceNotFoundException("Employee", "Id", id));
employeeRepository.delete(existingEmployee);
return existingEmployee;
}
@DeleteMapping("{id}")
public ResponseEntity<Employee> deleteEmployeeById(@PathVariable("id") long id){
return new ResponseEntity<Employee>(employeeService.deleteEmployeeById(id), HttpStatus.OK);
}