spring boot + JPA + mysql, unable to retrieve result set - mysql

Question

i am new to spring boot, having basic knowledge of java. i am trying to build a micro-service to retrieve data from mySQL database. below are the code details.
i am able to retrieve data from the same table using standalone JDBC class. request to help.
- Entity class
package com.studentProject.entity;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.springframework.stereotype.Component;
#Entity
#Component
#Table(name="students", schema="test_schema")
public class StudentEntity implements Serializable{
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue
#Column(name="id")
private Integer id;
#Column(name="name")
private String name;
#Column(name="course")
private String course;
#Column(name="country")
private String country;
#Column(name="phone")
private String phone;
public StudentEntity(Integer id, String name, String course, String country, String phone) {
super();
this.id = id;
this.name = name;
this.course = course;
this.country = country;
this.phone = phone;
}
public StudentEntity() {
super();
// TODO Auto-generated constructor stub
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCourse() {
return course;
}
public void setCourse(String course) {
this.course = course;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
}
-Repository Class
package com.studentProject.repository;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.studentProject.entity.StudentEntity;
#Repository
public interface StudentRepository extends CrudRepository<StudentEntity, Integer> {
StudentEntity findByName(String name);
StudentEntity findByCourse(String course);
}
-Controller class
package com.studentProject.controller;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import com.studentProject.entity.StudentEntity;
import com.studentProject.repository.StudentRepository;
#RestController
public class StudentController {
#Autowired
private StudentRepository studentRepository;
#Autowired
List<StudentEntity> studentList;
public StudentController(StudentRepository studentRepository, StudentEntity studentEntity,
List<StudentEntity> studentList) {
super();
this.studentRepository = studentRepository;
this.studentList = studentList;
}
#GetMapping("/getStudentDetails")
public Iterable<StudentEntity> getAllStudents(){
return studentRepository.findAll();
}
#GetMapping("/getStudentDetails/getByName")
public StudentEntity findByName(#RequestParam(value="name") String name) {
return studentRepository.findByName(name);
}
#GetMapping("/getStudentDetails/getById/{id}")
public Optional<StudentEntity> findById(#PathVariable(value="id") Integer id) {
return studentRepository.findById(id);
}
#GetMapping("/getStudentDetails/welcome")
public String welcome() {
return "hi brother welcome";
}
}
-Properties File
server.port = 8080
spring.datasource.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/
spring.datasource.username = root
spring.datasource.password = root
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.data.jpa.repositories.enabled=true
spring.jpa.show-sql = true
spring.jpa.hibernate.ddl-auto = none
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect
--Pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.StudentProject</groupId>
<artifactId>StudentProject-1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>StudentProject-1</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
-main application
package com.studentProject;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class StudentProject1Application {
public static void main(String[] args) {
SpringApplication.run(StudentProject1Application.class, args);
}
}
-mysql table details
schema=test_schema and table=students
error details

Answer 1

From the error log
Caused by: java.sql.SQLException: No database selected
it is clear that spring is not able to find database so select database by following below.
change the spring.datasource.url value to below by adding database name.
spring.datasource.url = jdbc:mysql://localhost:3306/test_schema

Answer 2

Caused by: java.sql.SQLException: No database selected at
This tells that you must select the database name, so you must add it in your config. I saw you already got an answer!
spring.datasource.url = jdbc:mysql://localhost:3306/YOUR_DB_SCHEMA