This an application to test crud operations in springboot

src/main/java/com/ebrains/cruddemo/CruddemoApplication.java

@@ -0,0 +1,124 @@
+package com.ebrains.cruddemo;
+
+import com.ebrains.cruddemo.dao.StudentDAO;
+import com.ebrains.cruddemo.entity.Student;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+import java.util.List;
+
+@SpringBootApplication
+public class CruddemoApplication {
+
+	public static void main(String[] args) {
+
+		SpringApplication.run(CruddemoApplication.class, args);
+	}
+
+	@Bean
+	public CommandLineRunner commandLineRunner(StudentDAO studentDAO) {
+		return runner ->{
+			createMultipleStudent(studentDAO);
+			//queryForStudent(studentDAO);
+			//queryForStudentByLastName(studentDAO);
+			//updateStudent(studentDAO);
+			//deleteStudent(studentDAO);
+			//deleteAllStudent(studentDAO);
+		};
+	}
+
+	private void deleteAllStudent(StudentDAO studentDAO) {
+		int numOfRowDeleted = studentDAO.deleteAll();
+		System.out.println("Number of row deleted: " + numOfRowDeleted);
+	}
+
+
+	private void deleteStudent(StudentDAO studentDAO) {
+		Student student = studentDAO.findById(3);
+		System.out.println("Student to be deleted: "+student);
+		studentDAO.delete(3);
+	}
+
+	private void updateStudent(StudentDAO studentDAO) {
+		//retrieve the student base on id
+		Student student = studentDAO.findById(1);
+
+		//change the lastname
+		System.out.println("updating the student ...");
+		student.setLastName("Lobby");
+
+		//update the student
+		studentDAO.update(student);
+
+		//Display the updated student
+		System.out.println("student updated: "+student);
+	}
+
+	private void queryForStudentByLastName(StudentDAO studentDAO) {
+		//get the list of student
+		List<Student> students = studentDAO.findByLastName("Doe");
+		for (Student student : students) {
+			System.out.println(student);
+		}
+	}
+
+	private void queryForStudent(StudentDAO studentDAO) {
+		//get the list of student
+		List<Student> students = studentDAO.findAll();
+
+		//display the student
+		for (Student student : students) {
+			System.out.println(student);
+		}
+	}
+
+	private void createStudent(StudentDAO studentDAO) {
+		System.out.println("Creating student ....");
+		Student student = new Student("paul","okeke","paul@gmail.com");
+
+		//saving the student object
+		System.out.println("saving student ....");
+		studentDAO.save(student);
+
+		System.out.println("Student saved successfully.Generated Id: " + student.getId());
+	}
+
+	private void createMultipleStudent(StudentDAO studentDAO) {
+		System.out.println("Creating student ....");
+		Student student = new Student("John","smith","smith@gmail.com");
+		Student student1 = new Student("Mary","Doe","doe@gmail.com");
+		Student student2= new Student("Eric","onu","onu@gmail.com");
+
+		//saving the multiple student object
+		studentDAO.save(student);
+		studentDAO.save(student1);
+		studentDAO.save(student2);
+
+		System.out.println("Students saved successfully");
+	}
+
+	private void readStudent(StudentDAO studentDAO) {
+		//create a student object
+		System.out.println("Creating student ....");
+		Student student = new Student("Onowu","Igbo","igbo@gmail.com");
+
+		//save the save
+		studentDAO.save(student);
+		System.out.println("Student saved successfully");
+
+		//display id of the saved student
+		long theId= student.getId();
+		System.out.println("saved student successfully.Generated Id: " + theId);
+
+		//retrieved the student based on the id ie the primary key
+		System.out.println("retrieving student saved successfully");
+		//Student savedStudent= studentDAO.findById(theId);
+
+		//display the student
+		//System.out.println("student retrieved successfully:  " + savedStudent);
+	}
+
+
+}

src/main/java/com/ebrains/cruddemo/dao/StudentDAO.java

@@ -0,0 +1,22 @@
+package com.ebrains.cruddemo.dao;
+
+import com.ebrains.cruddemo.entity.Student;
+
+import java.util.List;
+
+public interface StudentDAO {
+    void save(Student student);
+
+    Student findById(Integer id);
+
+    List<Student> findAll();
+
+    List<Student> findByLastName(String lastName);
+
+    void update(Student student);
+
+    void delete(Integer id);
+
+    int deleteAll();
+
+}

src/main/java/com/ebrains/cruddemo/dao/StudentDAOImpl.java

@@ -0,0 +1,79 @@
+package com.ebrains.cruddemo.dao;
+
+import com.ebrains.cruddemo.entity.Student;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.TypedQuery;
+import org.springframework.stereotype.Repository;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+
+@Repository
+public class StudentDAOImpl implements StudentDAO {
+    //we define feilds for entity manager
+    private EntityManager entityManager;
+
+    //eject entity manager using constructor injection
+    public StudentDAOImpl(EntityManager entityManager) {
+        this.entityManager = entityManager;
+    }
+
+    //implement the save method
+    //this method saves the studnet to the database
+    @Transactional
+    @Override
+    public void save(Student student) {
+        entityManager.persist(student);
+    }
+
+    @Override
+    public Student findById(Integer id) {
+        //Student.class is the entity class
+        return entityManager.find(Student.class, id);
+    }
+
+    @Override
+    public List<Student> findAll() {
+        //create the query
+        TypedQuery<Student> query = entityManager.createQuery("from Student", Student.class);
+        //TypedQuery<Student> query = entityManager.createQuery("from Student order by lastName desc", Student.class);
+
+        //return the list of student
+        return query.getResultList();
+    }
+
+    @Override
+    public List<Student> findByLastName(String lastName) {
+        //create the query
+        TypedQuery<Student> query = entityManager.createQuery("from Student where lastName=:theData", Student.class);
+
+        //set query parameter
+        query.setParameter("theData", lastName);
+
+        //return the list of student with the last name
+        return query.getResultList();
+    }
+
+    @Override
+    @Transactional
+    public void update(Student student) {
+        entityManager.merge(student);
+    }
+
+    @Override
+    @Transactional
+    public void delete(Integer id) {
+        //retrieve the student
+        Student student = entityManager.find(Student.class, id);
+
+        //delete the student
+        entityManager.remove(student);
+    }
+
+    @Override
+    @Transactional
+    public int deleteAll() {
+        return entityManager.createQuery("delete from Student").executeUpdate();
+
+    }
+}

src/main/java/com/ebrains/cruddemo/entity/Student.java

@@ -0,0 +1,70 @@
+package com.ebrains.cruddemo.entity;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name="student")
+public class Student {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "id")
+    private Long id;
+    @Column(name = "first_name")
+    private String firstName;
+    @Column(name = "last_name")
+    private String lastName;
+    @Column(name = "email")
+    private String email;
+
+    public Student() {
+
+    }
+    public Student(String firstName, String lastName, String email) {
+        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;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "id=" + id +
+                ", firstName='" + firstName + '\'' +
+                ", lastName='" + lastName + '\'' +
+                ", email='" + email + '\'' +
+                '}';
+    }
+}

src/main/resources/application.properties

@@ -0,0 +1,17 @@
+spring.application.name=cruddemo
+spring.datasource.url=jdbc:mysql://localhost:3306/student_tracker
+spring.datasource.username=springstudent
+spring.datasource.password=springstudent
+
+spring.jpa.hibernate.ddl-auto=update
+
+#Turn off the springboot logo
+spring.main.banner-mode=off
+
+#reduces logging level
+logging.level.root=warn
+
+#Add logging configs to displays SQL statements
+logging.level.org.hibernate.SQL= debug
+logging.level.org.hibernate.orm.jdbc.bind=trace
+

src/test/java/com/ebrains/cruddemo/CruddemoApplicationTests.java

@@ -0,0 +1,13 @@
+package com.ebrains.cruddemo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class CruddemoApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}