Jpa Repository instance is null in service layer

Jpa Repository instance is null in service layer - java

So i want to save the data with the help of JPA repository but when i autowired it is giving me null.
I don't know what else to do in here I have also tried with #EnableJPARepository annotation still no help. So here are the classes i am using. I want to save the data that is published by kafka so is it best to create a seperate function or can i put save to db function in consume json?
Repository
package com.prateek.addaKafka.addaKafka.kafkaConsumer;
import org.springframework.data.repository.CrudRepository;
public interface KafkaRepository extends CrudRepository<KafkaEntity,Long> {
}
KafkaEntityClass
package com.prateek.addaKafka.addaKafka.kafkaConsumer;
import javax.persistence.*;
#Entity
#Table(name = "messages")
public class KafkaEntity {
#Id
#GeneratedValue
private Long id;
#Column(nullable = false)
private String userName;
#Column(nullable = false)
private String userMessage;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserMessage() {
return userMessage;
}
public void setUserMessage(String userMessage) {
this.userMessage = userMessage;
}
}
ServiceClass
package com.prateek.addaKafka.addaKafka.kafkaConsumer;
import com.prateek.addaKafka.addaKafka.model.UserPublishModel;
import org.modelmapper.ModelMapper;
import org.modelmapper.convention.MatchingStrategies;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;
#Service
public class KafkaListenerService {
#Autowired
KafkaRepository kafkaRepository;
#KafkaListener(topics = "NewTopic",groupId = "group_json",
containerFactory = "userKafkaListenerFactory")
public UserPublishModel consumeJson(UserPublishModel userPublishModel) {
return userPublishModel;
}
public void saveToDB(UserPublishModel userPublishModel){
ModelMapper modelMapper=new ModelMapper();
modelMapper.getConfiguration().setMatchingStrategy(MatchingStrategies.STRICT);
KafkaEntity kafkaEntity=modelMapper.map(userPublishModel, KafkaEntity.class);
kafkaRepository.save(kafkaEntity);
}
}
MainClass
package com.prateek.addaKafka.addaKafka;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
#SpringBootApplication
public class AddaKafkaApplication {
public static void main(String[] args) {
SpringApplication.run(AddaKafkaApplication.class, args);
}
}

Related

ReactiveCosmosRepository delete functions not working

I'm building a Spring Boot app using CosmosDB as my database. All functions work (creating an item, updating one, get all, get by id,...), apart from delete functions. They don't do anything and since their output is void, it doesn't give me any logs either.
The DAO class:
package projects.trashcanapplication.trashcan.dao;
import com.azure.spring.data.cosmos.core.mapping.Container;
import com.azure.spring.data.cosmos.core.mapping.GeneratedValue;
import com.azure.spring.data.cosmos.core.mapping.PartitionKey;
import org.springframework.data.annotation.Id;
import projects.trashcanapplication.trashcan.models.Address;
import projects.trashcanapplication.trashcan.models.FillStatus;
#Container(containerName = "trashcanData")
public class TrashcanDao{
#GeneratedValue
private String attachments;
private FillStatus fillStatus;
#GeneratedValue
private String rid;
private Address address;
#Id
#PartitionKey
#GeneratedValue
private String id;
#GeneratedValue
private String self;
#GeneratedValue
private String etag;
#GeneratedValue
private int ts;
public TrashcanDao(Address address, FillStatus fillStatus) {
this.fillStatus = fillStatus;
this.address = address;
}
public String getAttachments(){
return attachments;
}
public FillStatus getFillStatus(){
return fillStatus;
}
public String getRid(){
return rid;
}
public Address getAddress(){
return address;
}
public String getId(){
return id;
}
public String getSelf(){
return self;
}
public String getEtag(){
return etag;
}
public int getTs(){
return ts;
}
}
The repository
package projects.trashcanapplication.trashcan.repositories;
import com.azure.spring.data.cosmos.repository.ReactiveCosmosRepository;
import projects.trashcanapplication.trashcan.dao.TrashcanDao;
public interface TrashcanRepository extends ReactiveCosmosRepository<TrashcanDao, String> {
}
The service calling the repository
package projects.trashcanapplication.trashcan.services;
import com.azure.cosmos.models.PartitionKey;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import projects.trashcanapplication.trashcan.dao.TrashcanDao;
import projects.trashcanapplication.trashcan.models.Trashcan;
import projects.trashcanapplication.trashcan.repositories.TrashcanRepository;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
#Slf4j
#Service
#AllArgsConstructor
public class TrashcanServiceImpl implements TrashcanService {
private final TrashcanRepository trashcanRepository;
private final TrashcanMapper trashcanMapper;
public Flux<Trashcan> getAllTrashcans() {
return trashcanRepository.findAll().map(trashcanMapper::fromDaoToTrashcan);
}
public Mono<Trashcan> getTrashcanById(String id) {
return trashcanRepository.findById(id).map(trashcanMapper::fromDaoToTrashcan);
}
public String createTrashcan(Trashcan trashcan) {
TrashcanDao saveTrashcan = trashcanMapper.fromTrashcanToDao(trashcan);
trashcanRepository.save(saveTrashcan).subscribe();
return saveTrashcan.getId();
}
public void deleteTrashcan(String id) {
trashcanRepository.deleteById(id, new PartitionKey(id));
log.info(String.format("Deleted trashcan %s", id));
}
}
I have a dataloader temporarily set up to populate my DB with an item upon running the app. The deleteAll() function doesn't work here either.
package projects.trashcanapplication.trashcan.services;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import projects.trashcanapplication.trashcan.dao.TrashcanDao;
import projects.trashcanapplication.trashcan.models.Address;
import projects.trashcanapplication.trashcan.models.FillStatus;
import projects.trashcanapplication.trashcan.repositories.TrashcanRepository;
import javax.annotation.PostConstruct;
#Slf4j
#Component
#AllArgsConstructor
public class DataLoader {
private final TrashcanRepository trashcanRepository;
#PostConstruct
void loadData() {
Address address1 = new Address("Begijnendijk", "3130", "Liersesteenweg", "181");
trashcanRepository.deleteAll();
trashcanRepository.save(new TrashcanDao(address1, FillStatus.EMPTY))
.flatMap(trashcanRepository::save)
.thenMany(trashcanRepository.findAll())
.subscribe(trashcan -> log.info(trashcan.getId().toString()))
;
}
}

You're not subscribing anywhere, so the reactive stream isn't executed.
You could solve that by subscribing manually:
trashcanRepository.deleteAll().subscribe()
However, this is not a good practice, and certainly not in your DataLoader as you can't guarantee the order in which the save/delete-logic is executed (maybe the TrashcanDao is saved before you delete everything).
To solve this, you should create a proper reactive stream:
trashcanRepository
.deleteAll()
.then(trashcanRepository.save(new TrashcanDao(address1, FillStatus.EMPTY)))
.thenMany(trashcanRepository.findAll())
// Your previous subscribe() shouldn't compile since it should contain List<TrashcanDao>
.subscribe(trashcans -> log.info(trashcans.size()));

The injection point has the following annotations: #org.springframework.beans.factory.annotation.Autowired(required=true)

Hello there I am new to spring boot, i am getting this error since a while, unfortunately can't fix it. I am googling since then but still not find what i did wrong. I believe the error exists in the Service Class. I tried to remove the field injection ( #Autowired) and implemented as a constructor injection but that did not work as well Find below my code:
Entity:
package com.devops.maven.cars_api_maven.model;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import javax.persistence.*;
#JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
#Entity
#Table(name = "CARS")
#SequenceGenerator(name="seq", initialValue=4, allocationSize=100)
public class Car {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE, generator="seq")
private Long id;
String manufacturer;
String model;
int build;
public Car() {
}
public Car(Long id, String manufacturer, String model, int build) {
this.id = id;
this.manufacturer = manufacturer;
this.model = model;
this.build = build;
}
public Long getId() {
return id;
}
public String getManufacturer() {
return manufacturer;
}
public String getModel() {
return model;
}
public int getBuild() {
return build;
}
public void setId(Long id) {
this.id = id;
}
public void setManufacturer(String manufacturer) {
this.manufacturer = manufacturer;
}
public void setModel(String model) {
this.model = model;
}
public void setBuild(int build) {
this.build = build;
}
}
DAO
package com.devops.maven.cars_api_maven.repositories;
import com.devops.maven.cars_api_maven.model.Car;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
#Repository
public interface CarsRepository extends JpaRepository<Car, Long> {
}
Main
package com.devops.maven.cars_api_maven;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
#SpringBootApplication (
exclude = {DataSourceAutoConfiguration.class },
scanBasePackages={
"com.devops.maven", "com.devop.application"}
)
public class CarsApplication {
public static void main(String[] args) {
SpringApplication.run(CarsApplication.class, args);
}
}
Service Class
package com.devops.maven.cars_api_maven;
import com.devops.maven.cars_api_maven.model.Car;
import com.devops.maven.cars_api_maven.repositories.CarsRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.*;
import java.util.List;
#RestController
#RequestMapping("cars")
#Service
public class CarsController {
#Autowired
private CarsRepository repository;
#GetMapping
public List<Car> getCars() {
return repository.findAll();
}
#PostMapping
public Car addCar(#RequestBody Car car) {
return repository.save(car);
}
#SuppressWarnings("deprecation")
#GetMapping(value = "/{id}")
public Car getCarById(#PathVariable("id") long id) {
return repository.getOne(id);
}
#DeleteMapping(value = "/{id}")
public void removeCarById(#PathVariable("id") long id) {
repository.deleteById(id);
}
}
Error output:
*************************** APPLICATION FAILED TO START
Description:
Field repository in com.devops.maven.cars_api_maven.CarsController
required a bean of type
'com.devops.maven.cars_api_maven.repositories.CarsRepository' that
could not be found.
The injection point has the following annotations:
#org.springframework.beans.factory.annotation.Autowired(required=true)
Action:
Consider defining a bean of type
'com.devops.maven.cars_api_maven.repositories.CarsRepository' in your
configuration.

Please remove exclude = {DataSourceAutoConfiguration.class } from below class and run again. It will fix the issue.
package com.devops.maven.cars_api_maven;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
#SpringBootApplication (
exclude = {DataSourceAutoConfiguration.class },
scanBasePackages={
"com.devops.maven", "com.devop.application"}
)
public class CarsApplication {
public static void main(String[] args) {
SpringApplication.run(CarsApplication.class, args);
}
}

Postman is returning a 404 error on my Spring Boot API

I've built a spring boot rest api. However, when I try to test it in Postman, I am getting a 404 error. I have linked the code below. Please note that there might be a random #component annotation in some files. This was my tired brain trying anything it can.
Student.java
package StudentModel;
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 = "Student")
public class Student {
public enum status {
PAID,
UNPAID,
PARTIAL
}
#Column
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private long Id;
#Column(nullable = false)
private String FirstName;
#Column(nullable = false)
private String LastName;
#Column(nullable = false)
private long Phone;
#Column(nullable = false)
private String Email;
#Column(nullable = false)
private status PaymentStatus;
public long getId() {
return Id;
}
public void setId(long id) {
Id = id;
}
public String getFirstName() {
return FirstName;
}
public void setFirstName(String firstName) {
FirstName = firstName;
}
public String getLastName() {
return LastName;
}
public void setLastName(String lastName) {
LastName = lastName;
}
public long getPhone() {
return Phone;
}
public void setPhone(long phone) {
Phone = phone;
}
public String getEmail() {
return Email;
}
public void setEmail(String email) {
Email = email;
}
public status getPaymentStatus() {
return PaymentStatus;
}
public void setPaymentStatus(status paymentStatus) {
PaymentStatus = paymentStatus;
}
}
StudentController.java
package StudentController;
import java.util.List;
import java.util.Optional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
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 StudentModel.Student;
import StudentService.StudentService;
#Component
#RestController
#RequestMapping("/api/v1")
public class StudentController {
#Autowired
private StudentService studentService;
#PostMapping("/api/v1/addStudent")
public Student addStudent(#RequestBody Student student) {
return studentService.saveStudent(student);
}
#PostMapping("/api/v1/addStudents")
public List<Student> addStudents(#RequestBody List<Student> students) {
return studentService.saveStudents(students);
}
#GetMapping("/api/v1/students")
public List<Student> findAllStudents(){
return studentService.getStudents();
}
#GetMapping("/api/v1/students/{id}")
public Student findStudentById(#PathVariable long id) {
return studentService.getStudentById(id);
}
#GetMapping("/api/v1/students/{name}")
public Student findStudentByFirstName(#PathVariable String FirstName) {
return studentService.getStudentByFirstName(FirstName);
}
#PutMapping("/api/v1/update")
public Student updateStudent(#RequestBody Student student) {
return studentService.updateStudent(student);
}
#DeleteMapping("/api/v1/delete/{id}")
public String deleteStudent(#PathVariable long id) {
return studentService.deleteStudent(id);
}
}
StudentService.java
package StudentService;
import java.util.List;
import java.util.Optional;
import javax.transaction.Transactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;
import StudentModel.Student;
import StudentRepository.StudentRepository;
#Component
#Service
#Transactional
public class StudentService {
#Autowired
private StudentRepository studentRepository;
public Student saveStudent(Student student) {
return studentRepository.save(student);
}
public List<Student> saveStudents(List<Student> students) {
return studentRepository.saveAll(students);
}
public List<Student> getStudents() {
return studentRepository.findAll();
}
public Student getStudentById(long id){
return studentRepository.getById(id);
}
public Student getStudentByFirstName(String FirstName){
return studentRepository.findByFirstName(FirstName);
}
public Student getStudentByLastName(String LastName){
return studentRepository.findByLastName(LastName);
}
public Student getStudentByEmail(String Email){
return studentRepository.findByEmail(Email);
}
public Student getStudentByPhone(long Phone){
return studentRepository.findByPhone(Phone);
}
public String deleteStudent(long id) {
studentRepository.deleteById(id);
return "Student Deleted";
}
public Student updateStudent (Student student) {
Student existingStudent = studentRepository.getById(student.getId());
existingStudent.setFirstName(student.getFirstName());
existingStudent.setLastName(student.getLastName());
existingStudent.setEmail(student.getEmail());
existingStudent.setPhone(student.getPhone());
existingStudent.setPaymentStatus(student.getPaymentStatus());
return studentRepository.save(existingStudent);
}
}
StudentRepository.java
package StudentRepository;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Component;
import StudentModel.Student;
#Component
public interface StudentRepository extends JpaRepository <Student, Long>{
// Student saveStudent (Student student);
Student findByFirstName(String FirstName);
Student findByLastName(String LastName);
Student findByEmail(String Email);
Student findByPhone(long Phone);
// Student findById(long id);
}
StudentApplication.java
package com.BusyQA;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
#SpringBootApplication
#ComponentScan
public class BusyQaApplication extends SpringBootServletInitializer{
public static void main(String[] args) {
SpringApplication.run(BusyQaApplication.class, args);
}
}
Any help would be greatly appreciated. Thank you.

To make it work, you need some improvements:
For Controller (REST API requests):
remove #Component annotation;
remove /api/v1/ from request mappings;
add DTO to only transfer the required information;
fix the name of the variables, following the convention.
import java.util.ArrayList;
import java.util.List;
import com.example.demo.dto.StudentDTO;
import com.example.demo.entity.Student;
import com.example.demo.service.StudentService;
import org.springframework.web.bind.annotation.*;
#RestController
#RequestMapping("/api/v1")
public class StudentController {
private final StudentService studentService;
public StudentController(StudentService studentService) {
this.studentService = studentService;
}
#PostMapping("/addStudent")
public Student addStudent(#RequestBody StudentDTO studentDTO) {
Student student = new Student(studentDTO);
return studentService.saveStudent(student);
}
#PostMapping("/addStudents")
public List<Student> addStudents(#RequestBody List<Student> students) {
return studentService.saveStudents(students);
}
#GetMapping("/students")
public List<StudentDTO> findAllStudents() {
List<StudentDTO> studentDTOList = new ArrayList<>();
List<Student> studentList = studentService.getStudents();
for (Student student : studentList) {
StudentDTO studentDTO = new StudentDTO(student);
studentDTOList.add(studentDTO);
}
return studentDTOList;
}
#GetMapping("/students/id/{id}")
public Student findStudentById(#PathVariable long id) {
return studentService.getStudentById(id);
}
#GetMapping("/students/firstName/{firstName}")
public Student findStudentByFirstName(#PathVariable String firstName) {
return studentService.getStudentByFirstName(firstName);
}
#PutMapping("/update")
public Student updateStudent(#RequestBody StudentDTO studentDTO) {
Student student = new Student(studentDTO);
return studentService.updateStudent(student);
}
#DeleteMapping("/delete/{id}")
public String deleteStudent(#PathVariable long id) {
return studentService.deleteStudent(id);
}
}
For Service class (Business logic):
remove #Component annotation;
remove #Transactional annotation;
use findById() to retrieve an entity by its Id;
import java.util.List;
import java.util.Optional;
import com.example.demo.entity.Student;
import com.example.demo.repository.StudentRepository;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.persistence.EntityNotFoundException;
#Service
public class StudentService {
private final StudentRepository studentRepository;
public StudentService(StudentRepository studentRepository) {
this.studentRepository = studentRepository;
}
public Student saveStudent(Student student) {
return studentRepository.save(student);
}
public List<Student> saveStudents(List<Student> students) {
return studentRepository.saveAll(students);
}
public List<Student> getStudents() {
return studentRepository.findAll();
}
public Student getStudentById(long id) {
return studentRepository.findById(id).orElseThrow(EntityNotFoundException::new);
}
public Student getStudentByFirstName(String firstName) {
return studentRepository.findByFirstName(firstName);
}
public Student getStudentByLastName(String lastName) {
return studentRepository.findByLastName(lastName);
}
public Student getStudentByEmail(String email) {
return studentRepository.findByEmail(email);
}
public Student getStudentByPhone(long phone) {
return studentRepository.findByPhone(phone);
}
public String deleteStudent(long id) {
studentRepository.deleteById(id);
return "Student Deleted";
}
public Student updateStudent(Student student) {
Student existingStudent = studentRepository.getById(student.getId());
existingStudent.setFirstName(student.getFirstName());
existingStudent.setLastName(student.getLastName());
existingStudent.setEmail(student.getEmail());
existingStudent.setPhone(student.getPhone());
existingStudent.setPaymentStatus(student.getPaymentStatus());
return studentRepository.save(existingStudent);
}
}
The Model class:
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import com.example.demo.dto.StudentDTO;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.Builder;
#Data
#Builder
#AllArgsConstructor
#NoArgsConstructor
#Entity
public class Student {
public Student(StudentDTO studentDTO) {
this.id = studentDTO.getId();
this.firstName = studentDTO.getFirstName();
this.lastName = studentDTO.getLastName();
this.phone = studentDTO.getPhone();
this.email = studentDTO.getEmail();
this.paymentStatus = studentDTO.getPaymentStatus();
}
public enum Status {
PAID,
UNPAID,
PARTIAL
}
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column
private long id;
private String firstName;
private String lastName;
private long phone;
private String email;
private Status paymentStatus;
}
DTO class:
import com.example.demo.entity.Student;
import com.fasterxml.jackson.annotation.JsonInclude;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.io.Serializable;
import static com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL;
#Builder
#Data
#NoArgsConstructor
#AllArgsConstructor
#JsonInclude(NON_NULL)
public class StudentDTO implements Serializable {
public StudentDTO(Student student) {
this.id = student.getId();
this.firstName = student.getFirstName();
this.lastName = student.getLastName();
this.phone = student.getPhone();
this.email = student.getEmail();
this.paymentStatus = student.getPaymentStatus();
}
private long id;
private String firstName;
private String lastName;
private long phone;
private String email;
private Student.Status paymentStatus;
}
The Repository class:
import com.example.demo.entity.Student;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
#Repository
public interface StudentRepository extends JpaRepository<Student, Long> {
Student findByFirstName(String firstName);
Student findByLastName(String lastName);
Student findByEmail(String email);
Student findByPhone(long phone);
}
and the main class of a Spring Boot application:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
To test it, you can use endpoints by the same principle:
POST: localhost:8080/api/v1/addStudent
POST: localhost:8080/api/v1/addStudents
GET: localhost:8080/api/v1/students
GET: localhost:8080/api/v1/students/id/1
GET: localhost:8080/api/v1/students/firstName/testName
PUT: localhost:8080/api/v1/update
DELETE: localhost:8080/api/v1/delete/1

As Dilermando mentioned in the comments, your #RequestMapping("/api/v1") is setting its mapping, then you're extending onto that with #PostMapping("/api/v1/addStudent") making the address {url}/api/v1/api/v1/addStudent. You can resolve this by removing the /api/v1 from the Post/get mappings:
#RequestMapping("/api/v1")
public class StudentController {
#Autowired
private StudentService studentService;
#PostMapping("/addStudent")
public Student addStudent(#RequestBody Student student) {
return studentService.saveStudent(student);
}
...etc
}

There are 2 reason behind 404 not found
Problem 1
You main class is in com.BusyQA package and Controller class is in StudentController package so you have to scan controller class in main class.
Your StudentApplication.java class should become:
#SpringBootApplication
#ComponentScan(basePackageClasses = StudentController.class) // Scan the controller class in main class.
public class BusyQaApplication extends SpringBootServletInitializer{
public static void main(String[] args) {
SpringApplication.run(BusyQaApplication.class, args);
}
}
Problem 2
Remove pre path /api/v1 from all url mapping in controller. Now your mapping url should become
#RestController
#RequestMapping("/api/v1")
public class StudentController {
#Autowired
private StudentService studentService;
#PostMapping("/addStudent")
#PostMapping("/addStudents")
#GetMapping("/students")
#GetMapping("/students/{id}")
#GetMapping("/students/{name}")
#PutMapping("/update")
#DeleteMapping("/delete/{id}")
}
This is another mistake in your code:
Remove the #Component annotation from controller.
Remove the #Component annotation from Service class.
Remove the #Component annotation from Repository interface and add #Repository annotation.

Spring Boot "Failed to execute CommandLineRunner Error"

I tried to add One To Many Annotation to my spring boot project, but when I run my project I get "Failed to execute CommandLineRunner " error.
I wanted users in the user's table to have more than one city. So, I tried to add OneToMany Annotation.
You can see the error at the attachment.
User Class
package io.javabrains.springsecurity.jpa.models;
import com.spring.weather.*;
import java.util.*;
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.OneToMany;
import javax.persistence.Table;
#Entity
#Table(name="app_user")
public class User {
#Id
#GeneratedValue(strategy =GenerationType.AUTO)
private int id;
private String userName;
private String password;
private boolean active;
private String role;
private String city;
#OneToMany(targetEntity = UserCity.class,cascade = CascadeType.ALL)
#JoinTable(name="USER_CITY",joinColumns=#JoinColumn(name="m_user_id"),
inverseJoinColumns=#JoinColumn(name="cityId"))
private List<UserCity> usercity;
public User() {
super();
// TODO Auto-generated constructor stub
}
public List<UserCity> getUsercity() {
return usercity;
}
public void setUsercity(List<UserCity> usercity) {
this.usercity = usercity;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean isActive() {
return active;
}
public void setActive(boolean active) {
this.active = active;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
User City Class
package io.javabrains.springsecurity.jpa.models;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
#Entity
#Table(name="user_city")
public class UserCity {
#Id
#GeneratedValue(strategy =GenerationType.AUTO)
private int cityId;
private String cityName;
public UserCity() {
super();
// TODO Auto-generated constructor stub
}
public UserCity(int cityId, String cityName, User mUser) {
super();
this.cityId = cityId;
this.cityName = cityName;
this.mUser = mUser;
}
#ManyToOne
private User mUser;
public int getCityId() {
return cityId;
}
public void setCityId(int cityId) {
this.cityId = cityId;
}
public String getCityName() {
return cityName;
}
public void setCityName(String cityName) {
this.cityName = cityName;
}
public User getmUser() {
return mUser;
}
public void setmUser(User mUser) {
this.mUser = mUser;
}
}
User Repository
package io.javabrains.springsecurity.jpa;
import java.util.Optional;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import io.javabrains.springsecurity.jpa.models.User;
public interface UserRepository extends JpaRepository<User, Integer> {
Optional<User> findByUserName(String userName);
}
User City Repository
package io.javabrains.springsecurity.jpa;
import org.springframework.data.jpa.repository.JpaRepository;
import io.javabrains.springsecurity.jpa.models.User;
import io.javabrains.springsecurity.jpa.models.UserCity;
public interface CityRepository extends JpaRepository<UserCity,id>{
}
Spring Application Class
package io.javabrains.springsecurity.jpa;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import com.spring.weather.WeatherService;
import io.javabrains.springsecurity.jpa.models.User;
import io.javabrains.springsecurity.jpa.models.UserCity;
#SpringBootApplication
#EnableJpaRepositories(basePackageClasses = UserRepository.class)
public class SpringsecurityApplication implements CommandLineRunner{
#Bean
public WeatherService ws() {
return new WeatherService ();
}
#Autowired
UserRepository userRepository;
CityRepository cityRepository;
public static void main(String[] args) {
SpringApplication.run(SpringsecurityApplication.class, args);
}
#Override
public void run(String... args) throws Exception {
// TODO Auto-generated method stub
System.out.println("Application Running.");
User adminUser= new User();
UserCity ucity=new UserCity();
UserCity ucity2=new UserCity();
ucity.setCityName("amsterdam");
adminUser.setUserName("Admin");
adminUser.setPassword(new BCryptPasswordEncoder().encode("pass"));
adminUser.setRole("ROLE_ADMIN");
adminUser.setActive(true);
adminUser.setCity("bologna");
ucity.setmUser(adminUser);
userRepository.save(adminUser);
cityRepository.save(ucity);
User newUser= new User();
newUser.setUserName("User");
newUser.setPassword(new BCryptPasswordEncoder().encode("pass"));
newUser.setRole("ROLE_USER");
newUser.setActive(true);
newUser.setCity("maribor");
ucity2.setmUser(newUser);
userRepository.save(newUser);
cityRepository.save(ucity2);
}
}

The problem you are encountering, more specifically the NullPointerException at line 54 of your main application, is caused by the fact that the cityRepository is not
instantiated.
Looking through your configuration, I see that you only register the UserRepository with the #EnableJpaRepositories annotation.
Try adding also the CityRepository to the #EnableJpaRepositories, and also specify this bean as a candidate for autowiring( also add #Autowired to this bean, as you did for UserRepository)
For a good practice, following the MVC structure, it would be nice is all your spring repositories, the beans responsible for all CRUD operations with the database to be under the same package

findById() not working on spring boot and Jpa

My main class is :
package com.ashwin.jpafirst;
import com.ashwin.jpafirst.model.Person;
import com.ashwin.jpafirst.reposit.PersonJpaRepository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class JpafirstApplication implements CommandLineRunner {
private Logger logger= LoggerFactory.getLogger(this.getClass());
#Autowired
PersonJpaRepository personJpaRepository;
public static void main(String[] args)
{
SpringApplication.run(JpafirstApplication.class, args);
}
#Override
public void run(String... args) throws Exception {
// TODO Auto-generated method stub
logger.info("User id is ",personJpaRepository.findById(2));
}
}
Person.java
package com.ashwin.jpafirst.model;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
#Entity
#Table(name="person")
public class Person {
#Id
#GeneratedValue
private int id;
#Column(name="name")
private String name;
private String location;
private Date dateOfBirth;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public Date getDateOfBirth() {
return dateOfBirth;
}
public void setDateOfBirth(Date dateOfBirth) {
this.dateOfBirth = dateOfBirth;
}
public Person(int id, String name, String location, Date dateOfBirth) {
this.id = id;
this.name = name;
this.location = location;
this.dateOfBirth = dateOfBirth;
}
public Person() {
}
}
my application properties is:
## Spring DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.url = jdbc:mysql://localhost:3306/jpaintro
spring.datasource.username = root
spring.datasource.password =
## Hibernate Properties
# The SQL dialect makes Hibernate generate better SQL for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
# Hibernate ddl auto (create, create-drop, validate, update)
spring.jpa.hibernate.ddl-auto = update
PersonJpaRepository.java
package com.ashwin.jpafirst.reposit;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import com.ashwin.jpafirst.model.Person;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
#Repository
#Transactional
public class PersonJpaRepository {
//connects to Databse
#PersistenceContext
EntityManager entityManager;
public Person findById(int id) {
return entityManager.find(Person.class, id);
}
}
I have also data saved in database as:
But when I try to receive the Person object by Id using
logger.info("User id is ",personJpaRepository.findById(2));
I am just getting as :
As Person object needs to print there,but the code is successfully compiling but I am not getting the information regarding the person.My code has no error but it is not retrieving the data.Why is the Person object not printing in the console?

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Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Jpa Repository instance is null in service layer - java

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