Not able to see actual uploaded file(.pdf format) format on database and postman?

i am trying to do create a user entity along with a data/file (pdf format).Uploaded and save to database is fine but when i get the user into postman try to send get request method then in the data field show some terrible data and also i can not see my pdf file into my database.
#pom.xml

<properties>
	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
	<java.version>1.8</java.version>
</properties>

<dependencies>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-jpa</artifactId>
	</dependency>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
	</dependency>

	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
		<scope>runtime</scope>
	</dependency>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-test</artifactId>
		<scope>test</scope>
		<exclusions>
			<exclusion>
				<groupId>org.junit.vintage</groupId>
				<artifactId>junit-vintage-engine</artifactId>
			</exclusion>
		</exclusions>
	</dependency>
</dependencies>

#Model Class

@Entity(name = "employee")

public class Employee {

@Id
@GeneratedValue
private Integer id;

@Column(nullable = false, length = 30)
private String name;

@Column(nullable = false, length = 30)
private String university;

@Column(nullable = false, length = 30)
private String department;

@Column(nullable = false, length = 2)
private Integer year_of_experience;

@Lob
private byte[] data;

2. Contoller Class

   @GetMapping
   public List<Employee> getAllEmployee(){
   return employeeService.getAllEmployee();
   }

   @GetMapping("{id}")
   public Employee getEmployeeById(@PathVariable Integer id){
   return employeeService.getEmployeeById(id);
   }

   @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE,
   produces = MediaType.APPLICATION_JSON_VALUE)
   public void addEmployee(@RequestParam("file") MultipartFile file, @RequestParam("emp") String emp ) throws IOException {
   ObjectMapper objectMapper = new ObjectMapper();
   Employee employee = objectMapper.readValue(emp,Employee.class);
   employeeService.addEmployee(employee,file);
   }
   #ServiceImplemention Class

   @Override
   public void addEmployee(Employee employee, MultipartFile file) throws IOException {

   for (int i = 0; i < employee.getExperienceList().size(); i++) {
       Experience experience = employee.getExperienceList().get(i);
       experienceService.addExperience(experience);
   }
   

   byte[] temp = file.getBytes();
   InputStream inputStream = new ByteArrayInputStream(temp);
   employee.setData(temp);

   employeeRepostitory.save(employee);
   

   }

#Postman view to get employee.
post method set with "form-data" in header and select key as a file and next key is my user entiy key as a text.i also try with content type (applicaiton/json) but not working.How can i convert to this unexpected data to a pdf file or something stranded format to see.

"id": 62,
    "name": "raj",
    "university": "ewu",
    "department": "bba",
    "year_of_experience": 3,
    "data": "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

You should take a look at the community project Spring Content. This project gives you a Spring Data-like approach to content. It is for unstructured data (documents, images, videos, etc), what Spring Data is for structured data.

You could add it to your project with something like this:-

> pom.xml

   <!-- Java API -->
   <dependency>          
      <groupId>com.github.paulcwarren</groupId>
      <artifactId>spring-content-jpa-boot-starter</artifactId>
	  <version>1.0.0.M9</version>
   </dependency>
   <!-- REST API -->
   <dependency>
      <groupId>com.github.paulcwarren</groupId>
      <artifactId>spring-content-rest-boot-starter</artifactId>
	  <version>1.0.0.M9</version>
   </dependency>

> Configuration

@Configuration
@EnableJpaStores
// enable REST API
@Import("org.springframework.content.rest.config.RestConfiguration.class") 
public class ContentConfig {
}

> NB: technically this configuration is not needed when using the Spring Boot starters, but included for clarity

To associate content, add Spring Content annotations to your account entity.

> Enployee.java

@Entity
public class Employee {

   // replace @Lob field with:

   @ContentId
   private String contentId;
	
   @ContentLength
   private long contentLength = 0L;
	
   @MimeType
   private String mimeType = "application/pdf";

Create a "store":

> EmployeeContentStore.java

@StoreRestResource
public interface EmployeeContentStore extends ContentStore<Employee, String> {
}

This is all you need to create REST endpoints for handling your employee's content under the URI /employees. When your application starts, Spring Content will look at your dependencies (seeing Spring Content JPA and REST), look at your UserContentStore interface and inject an implementation of that interface for JPA. It will also inject an @Controller that forwards http requests to that implementation. This saves you having to implement any of this yourself. So, very similar in programming model and operation to Spring Data.

Then...

curl -X POST /employees/{employeeId} -H "Content-Type: application/pdf" -F "file=@/path/to/local/file.pdf"

will store the content of /path/to/local/file.pdf in the database and associate it with the employee entity whose id is employeeId.

curl /employees/{employeeId} -H "Accept: application/pdf"

will fetch it again and so on...supports full CRUD.

Since you are associating the content with your employee entity, when you get your json responses back from the Spring Data endpoints, they will provide the content-related metadata, but NOT the "terrible data" that you are seeing with your current approach.

There are a couple of getting started guides and videos here. The reference guide is here.

HTH