validation

student-service/student-service/src/main/resources/application.properties

 server.port = 8082
-spring.jpa.hibernate.ddl-auto=update
+spring.jpa.hibernate.ddl-auto=none
 spring.jpa.defer-datasource-initialization=true
 spring.sql.init.mode=always
 spring.datasource.url=jdbc:mysql://localhost:3306/school

teacher-service/teacher-service/pom.xml

@@ -41,6 +41,16 @@
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+        <dependency>
+            <groupId>javax.validation</groupId>
+            <artifactId>validation-api</artifactId>
+            <version>2.0.1.Final</version>
+        </dependency>
+		<dependency>
+			<groupId>org.hibernate.validator</groupId>
+			<artifactId>hibernate-validator</artifactId>
+			<version>6.2.3.Final</version>
+		</dependency>
 	</dependencies>
 
 	<build>

teacher-service/teacher-service/src/main/java/com/example/teacher/controller/TeacherController.java

 package com.example.teacher.controller;
 
 
+import com.example.teacher.custom_exception.TeacherNotFoundException;
 import com.example.teacher.model.Teacher;
 import com.example.teacher.service.TeacherService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
+import javax.validation.Valid;
 import java.util.List;
 import java.util.Optional;
 
@@ -20,14 +23,15 @@ public class TeacherController {
 
     // POST methods
     @PostMapping
-    public ResponseEntity<Teacher> createTeacher(@RequestBody Teacher teacher) {
-        Teacher myStudent = teacherService.createAndUpdateTeacher(teacher);
-        return new ResponseEntity<Teacher>(myStudent, HttpStatus.CREATED);
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    public ResponseEntity<Teacher> createTeacher(@Valid @RequestBody Teacher teacher) {
+        Teacher myTeacher = teacherService.createAndUpdateTeacher(teacher);
+        return new ResponseEntity<Teacher>(myTeacher, HttpStatus.CREATED);
     }
 
     // GET methods
     @GetMapping("/{id}")
-    public ResponseEntity<Optional<Teacher>> findTeacherById(@PathVariable int id) {
+    public ResponseEntity<Optional<Teacher>> findTeacherById(@PathVariable int id) throws TeacherNotFoundException {
         Optional<Teacher> myTeacher = teacherService.findTeacherById(id);
         if (myTeacher.isPresent()) {
             return new ResponseEntity<Optional<Teacher>>(myTeacher, HttpStatus.FOUND);

teacher-service/teacher-service/src/main/java/com/example/teacher/custom_exception/TeacherNotFoundException.java

+package com.example.teacher.custom_exception;
+
+public class TeacherNotFoundException extends Exception{
+    public TeacherNotFoundException(String message){
+        super(message);
+    }
+}

teacher-service/teacher-service/src/main/java/com/example/teacher/exception_advice/MyExceptionHandlerAdvice.java

+package com.example.teacher.exception_advice;
+
+import com.example.teacher.custom_exception.TeacherNotFoundException;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@RestControllerAdvice
+public class MyExceptionHandlerAdvice{
+
+    @ResponseStatus(HttpStatus.UNPROCESSABLE_ENTITY)
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public Map<String, String> handleArgumentNotValidException(MethodArgumentNotValidException ex) {
+        Map<String, String> errors = new HashMap<>();
+        ex.getBindingResult().getFieldErrors().forEach(x -> {
+            errors.put(x.getField(), x.getDefaultMessage());
+        });
+        return errors;
+    }
+
+    @ResponseStatus(HttpStatus.NOT_FOUND)
+    @ExceptionHandler(TeacherNotFoundException.class)
+    public String handleTeacherNotFoundException(TeacherNotFoundException ex) {
+        return ex.getMessage();
+    }
+
+}

teacher-service/teacher-service/src/main/java/com/example/teacher/model/Teacher.java

@@ -6,6 +6,7 @@ import lombok.Data;
 import lombok.NoArgsConstructor;
 
 import javax.persistence.*;
+import javax.validation.constraints.*;
 import java.util.Date;
 
 @Entity
@@ -16,8 +17,12 @@ public class Teacher {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private int id;
+    @NotBlank(message = "teacher name should not be blank or null")
     private String name;
+    @Min(value = 24, message = "age should not be less than 24")
+    @Max(value = 65, message = "age should not be greater than 65")
     private int age;
+    @NotBlank(message = "teacher subject should not be blank or null")
     private String subject;
     @JsonFormat(shape=JsonFormat.Shape.STRING, pattern="dd:MM:yyyy")
     @Temporal(TemporalType.DATE)

teacher-service/teacher-service/src/main/java/com/example/teacher/service/TeacherService.java

 package com.example.teacher.service;
 
+import com.example.teacher.custom_exception.TeacherNotFoundException;
 import com.example.teacher.model.Teacher;
 import com.example.teacher.repository.TeacherRepository;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -29,10 +30,11 @@ public class TeacherService {
                 .collect(Collectors.toList());
     }
 
-    public Optional<Teacher> findTeacherById(int id) {
-        return teacherRepository
+    public Optional<Teacher> findTeacherById(int id) throws TeacherNotFoundException {
+        return Optional.ofNullable(teacherRepository
                 .findById(id)
-                .filter(Teacher::isActive);
+                .filter(Teacher::isActive)
+                .orElseThrow(() -> new TeacherNotFoundException("teacher with id"+ id + " found")));
     }
 
     public Optional<Teacher> findTeacherByName(String name) {