- spring data JPA covered

- Data Layer Repositories covered
- Autowiring Repositories (Data Layer) to Service Layer Covered
- Mapping Entities To Tables and Column attributes covered
- Transient annotation covered
- persisting data to DB through data layer covered

src/main/java/com/example/springcrashcourse/student/Student.java

@@ -1,24 +1,51 @@
 package com.example.springcrashcourse.student;
 
 import java.time.LocalDate;
+import java.time.Period;
 
+import jakarta.persistence.Table;
+import jakarta.persistence.Transient;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.SequenceGenerator;
+
+@Entity
+@Table
 public class Student {
+    @Id
+    @SequenceGenerator(
+        name = "student_sequence",
+        sequenceName = "student_sequence",
+        allocationSize = 1
+    )
+    @GeneratedValue(
+        strategy = GenerationType.SEQUENCE,
+        generator = "student_sequence"
+    )
     private Long id;
     private String name;
     private String email;
     private LocalDate dob;
+    @Transient
     private Integer age;
 
     public Student() {
 
     }
 
-    public Student(Long id, String name, String email, LocalDate dob, Integer age) {
+    public Student(String name, String email, LocalDate dob) {
+        this.name = name;
+        this.email = email;
+        this.dob = dob;
+    }
+
+    public Student(Long id, String name, String email, LocalDate dob) {
         this.id = id;
         this.name = name;
         this.email = email;
         this.dob = dob;
-        this.age = age;
     }
 
     public Long getId() {
@@ -54,7 +81,7 @@ public class Student {
     }
 
     public Integer getAge() {
-        return this.age;
+        return Period.between(this.dob, LocalDate.now()).getYears();
     }
 
     public void setAge(Integer age) {

src/main/java/com/example/springcrashcourse/student/StudentConfig.java

@@ -0,0 +1,33 @@
+package com.example.springcrashcourse.student;
+
+import java.util.List;
+
+import java.time.LocalDate;
+import java.time.Month;
+
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class StudentConfig {
+    
+    @Bean
+    CommandLineRunner commandLineRunner(StudentRepository repository) {
+        return args -> {
+            Student mariam = new Student(
+                "Mariam",
+                "mariam.jamal@gmail.com", 
+                LocalDate.of(2000, Month.JANUARY, 5)
+            );
+
+            Student alex = new Student(
+                "Alex",
+                "alex.jamal@gmail.com",
+                LocalDate.of(2004, Month.JANUARY, 5)
+            );
+
+            repository.saveAll(List.of(mariam, alex));
+        };
+    };
+}

src/main/java/com/example/springcrashcourse/student/StudentRepository.java

@@ -0,0 +1,9 @@
+package com.example.springcrashcourse.student;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface StudentRepository extends JpaRepository<Student, Long> {
+    
+}

src/main/java/com/example/springcrashcourse/student/StudentService.java

@@ -4,19 +4,20 @@ import java.time.LocalDate;
 import java.time.Month;
 import java.util.List;
 
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 @Service
 public class StudentService {
+
+    private final StudentRepository studentRepository;
+
+    @Autowired
+    public StudentService(StudentRepository studentRepository) {
+        this.studentRepository = studentRepository;
+    }
+
     public List<Student> getStudents() {
-        return List.of(
+        return studentRepository.findAll();
-            new Student(
-                1L,
-                "Mariam",
-                "mariam.jamal@gmail.com",
-                LocalDate.of(2000, Month.JANUARY, 5),
-                21
-            )
-        );
     }
 }

src/main/resources/application.properties

@@ -1,8 +1,8 @@
 
 spring.datasource.url=jdbc:postgresql://localhost:5432/student
-spring.datasource.username=
+spring.datasource.username=postgres
-spring.datasource.password=
+spring.datasource.password=testing
 spring.jpa.hibernate.ddl-auto=create-drop
 spring.jpa.show-sql=true
-spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgresSQLDialect
+spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
 spring.jpa.properties.hibernate.format_sql=true