How to use Spring Boot with MySQL database and JPA

Question

I want to setting Spring Boot with MySQL and JPA  For this I create  Person  package domain   import javax persistence      Entity  Table name    person   public class Person     Id  GeneratedValue private Long id    Column nullable   false  private String firstName      setters and getters     PersonRepository  package repository   import domain Person  import org springframework data domain Page  import org springframework data domain Pageable  import org springframework data repository CrudRepository    public interface PersonRepository extends CrudRepository lt Person  Long gt     Page lt Person gt  findAll Pageable pageable       PersonController  package controller   import domain Person  import org springframework beans factory annotation Autowired  import org springframework stereotype Controller  import org springframework web bind annotation RequestMapping  import org springframework web bind annotation ResponseBody  import repository PersonRepository    Controller public class PersonController     Autowired private PersonRepository personRepository    RequestMapping       ResponseBody public String test         Person person   new Person        person setFirstName  First        person setLastName  Test        personRepository save person       return  hello         Start class Example   import org springframework boot SpringApplication  import org springframework boot autoconfigure SpringBootApplication    SpringBootApplication public class Example    public static void main String   args  throws Exception       SpringApplication run Example class  args          And for database configuration  I create application properties  spring jpa hibernate ddl-auto create-drop spring jpa properties hibernate globally quoted identifiers true  spring datasource url jdbc mysql   localhost test spring boot spring datasource username root spring datasource password root spring datasource driverClassName com mysql jdbc Driver   So I have project structure     But as a result I have exceptions   org springframework beans factory BeanDefinitionStoreException  Failed to parse configuration class  Example   nested exception is java io FileNotFoundException  class path resource  org springframework security config annotation authentication configurers GlobalAuthenticationConfigurerAdapter class  cannot be opened because it does not exist   As a example I use   spring-boot-sample-data-jpa pom xml

User · Answer

Your code is in the default package  i e  you have source all files in src main java with no custom package  I strongly suggest u to create package n then place your source file in it  Ex-  src- gt       main- gt            java- gt                  com myfirst example                    Example java                 com myfirst example controller                    PersonController java                 com myfirst example repository                   PersonRepository java                 com myfirst example model                    Person java  I hope it will resolve your problem

User · Answer

When moving classes into specific packages like repository  controller  domain just the generic  SpringBootApplication is not enough    You will have to specify the base package for component scan   ComponentScan  base package     For JPA    EnableJpaRepositories basePackages    repository     is also needed  so spring data will know where to look into for repository interfaces

User · Answer

For Jpa based application  base package scan  EnableJpaRepositories basePackages    quot repository quot   You can try it once    Project Structure com   - stack       - app           - Application java       - controller           - EmployeeController java       - service           - EmployeeService java       - repository           - EmployeeRepository java       - model           - Employee java -pom xml dependencies       mysql  lombok  data-jpa  application properties  Data source   spring datasource url jdbc mysql   localhost 3306 employee useSSL false spring datasource username root spring datasource password root spring jpa generate-ddl true spring datasource driverClassName com mysql jdbc Driver   Jpa Hibernate   spring jpa show-sql true spring jpa properties hibernate dialect   org hibernate dialect MySQL5Dialect spring jpa hibernate ddl-auto   update  Employee java  Entity  Table  name    quot employee quot    Getter  Setter public class Employee         Id      GeneratedValue  strategy   GenerationType IDENTITY      private Long id        Column  name    quot first name quot       private String firstName       Column  name    quot last name quot       private String lastName       Column  name    quot email quot       private String email       Column  name    quot phone number quot       private String phoneNumber       Column  name    quot emp desg quot       private String desgination     EmployeeRepository java  Repository public interface EmployeeRepository extends JpaRepository lt Employee  Long gt       EmployeeController java  RestController public class EmployeeController         Autowired     private EmployeeService empService        GetMapping  value    quot  employees quot       public List lt Employee gt  getAllEmployee            return empService getAllEmployees                PostMapping  value    quot  employee quot       public ResponseEntity lt Employee gt  addEmp  RequestBody Employee emp  HttpServletRequest                                           request  throws URISyntaxException           HttpHeaders headers   new HttpHeaders            headers setLocation new URI request getRequestURI      quot   quot    emp getId              empService saveEmployee emp           return new ResponseEntity lt Employee gt  emp  headers  HttpStatus CREATED          EmployeeService java public interface EmployeeService       public List lt Employee gt  getAllEmployees        public Employee saveEmployee Employee emp       EmployeeServiceImpl java  Service  Transactional public class EmployeeServiceImpl implements EmployeeService         Autowired     private EmployeeRepository empRepository        Override     public List lt Employee gt  getAllEmployees             return empRepository findAll                Override     public Employee saveEmployee Employee emp            return empRepository save emp             EmployeeApplication java  SpringBootApplication  EnableJpaRepositories basePackages    quot repository quot   public class EmployeeApplication       public static void main String   args            SpringApplication run EmployeeApplication class  args

User · Answer

I created a project like you did  The structure looks like this    The Classes are just copy pasted from yours   I changed the application properties to this   spring datasource url jdbc mysql   localhost testproject spring datasource username root spring datasource password root spring datasource driverClassName com mysql jdbc Driver spring jpa hibernate ddl-auto update   But I think your problem is in your pom xml    lt  xml version  1 0  encoding  UTF-8   gt   lt project xmlns  http   maven apache org POM 4 0 0  xmlns xsi  http   www w3 org 2001 XMLSchema-instance  xsi schemaLocation  http   maven apache org POM 4 0 0 http   maven apache org xsd maven-4 0 0 xsd  gt   lt modelVersion gt 4 0 0 lt  modelVersion gt    lt parent gt       lt groupId gt org springframework boot lt  groupId gt       lt artifactId gt spring-boot-starter-parent lt  artifactId gt       lt version gt 1 4 1 RELEASE lt  version gt   lt  parent gt    lt artifactId gt spring-boot-sample-jpa lt  artifactId gt   lt name gt Spring Boot JPA Sample lt  name gt   lt description gt Spring Boot JPA Sample lt  description gt    lt dependencies gt       lt dependency gt           lt groupId gt mysql lt  groupId gt           lt artifactId gt mysql-connector-java lt  artifactId gt       lt  dependency gt       lt dependency gt           lt groupId gt org springframework boot lt  groupId gt           lt artifactId gt spring-boot-starter-web lt  artifactId gt       lt  dependency gt       lt dependency gt           lt groupId gt org springframework boot lt  groupId gt           lt artifactId gt spring-boot-starter-data-jpa lt  artifactId gt       lt  dependency gt   lt  dependencies gt   lt build gt       lt plugins gt           lt plugin gt               lt groupId gt org springframework boot lt  groupId gt               lt artifactId gt spring-boot-maven-plugin lt  artifactId gt           lt  plugin gt       lt  plugins gt   lt  build gt      Check these files for differences  Hope this helps  Update 1  I changed my username  The link to the example is now https   github com Yannic92 stackOverflowExamples tree master SpringBoot MySQL

User · Answer

You can move Application java to a folder under the java

User · Answer

In the spring boot reference it said      When a class doesn   t include a package declaration it is considered to be in the    default package     The use of the    default package    is generally discouraged  and should be avoided  It can cause particular problems for Spring Boot applications that use  ComponentScan   EntityScan or  SpringBootApplication annotations  since every class from every jar  will be read    com   - example       - myproject           - Application java                      - domain               - Customer java               - CustomerRepository java                      - service               - CustomerService java                      - web               - CustomerController java   In your cases  You must add scanBasePackages in the  SpringBootApplication annotation just like SpringBootApplication scanBasePackages   domain   contorller

[java] How to use Spring Boot with MySQL database and JPA?

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