findOne(Example<S>) は引数 (Integer) にさせたい

Question

findOne(Example<S>) は引数 (Integer) にさせたい

Spring Bootで会員情報管理システムを作っています。
会員情報取得機能を実装中にCustomerService.Javaで以下のエラーメッセージが発生しました。

発生している問題・エラーメッセージ

型 QueryByExampleExecutor<Customer> のメソッド findOne(Example<S>) は引数 (Integer) に適用できません
型 CrudRepository<Customer,Integer> のメソッド delete(Customer) は引数 (Integer) に適用できません

Customer.java

package com.example.domain;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;

@Entity
@Table(name = "customers") 
@Data
@NoArgsConstructor 
@AllArgsConstructor
public class Customer {
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    @Column(nullable = false)
    private String firstName;
    @Column(nullable = false)
    private String lastName;
} 

CustomerService.java

package com.example.service;

import com.example.domain.Customer;
import com.example.repository.CustomerRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;


@Service
@Transactional
public class CustomerService {
    @Autowired
    CustomerRepository customerRepository;

    public List<Customer> findAll() {
        return customerRepository.findAllOrderByName();
    }

    public Customer findOne(Integer id) {
        return customerRepository.findOne(id);
    }

    public Customer create(Customer customer) {
        return customerRepository.save(customer);
    }

    public Customer update(Customer customer) {
        return customerRepository.save(customer);
    }

    public void delete(Integer id) {
        customerRepository.delete(id);
    }
}

CustomerRepository.java

package com.example.repository;

import com.example.domain.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

public interface CustomerRepository extends JpaRepository<Customer, Integer> {
	@Query("SELECT x FROM Customer x ORDER BY x.firstName, x.lastName")
	List<Customer> findAllOrderByName();

}

CustomerRestController.java

package com.example.api;
import com.example.domain.Customer;
import com.example.service.CustomerService;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("api/customers")
public class CustomerRestController {
	@Autowired
	CustomerService customerService;
	
	@GetMapping
	List<Customer> getCustomers() {
		List<Customer> customers = customerService.findAll();
		return customers;
	}
	@GetMapping(path = "{id}")
	Customer getCustomer(@PathVariable Integer id) {
	Customer customer = customerService.findOne(id);
	return customer;
	}
}

HajibootRestApplication.java

ソースコードpackage com.example.hajibootrest;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class HajibootRestApplication {

	public static void main(String[] args) {
		SpringApplication.run(HajibootRestApplication.class, args);
	}

}```


### 補足情報（FW/ツールのバージョンなど）

Spring Boot
Spring Tool Suite4

Answer 1

Spring Boot 1.xの時は、findOne(id)とdelete(id)でしたが
Spring Boot 2.xでは、findById(id)とdeleteById(id)にメソッド名が変更になっています。

//customerRepository.findOne(id);
customerRepository.findById(id);

//customerRepository.delete(id);
customerRepository.deleteById(id);

参考: Spring公式のissue

---

■追記

Optionalは、色々書き方がありますが、例えば以下のようなことができます。

public Customer findOne(Integer id) {
    return customerRepository.findById(id).orElseThrow(() -> 
            new EntityNotFoundException("Customer not found with id " + id));
}

Comments

[arin]

ありがとうございます。
customerRepository.findById(id);と記述したところ下記のエラーが出ました。
型の不一致: Optional<Customer> から Customer には変換できません
さら修正を下記のようにしたらこのようなエラーが出ました。
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: net.sf.log4jdbc.DriverSpy

### CustomerService.java

```Java
package com.example.service;

import com.example.domain.Customer;
import com.example.repository.CustomerRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;
import java.util.Optional;

@Service
@Transactional
public class CustomerService {
@Autowired
CustomerRepository customerRepository;

public List<Customer> findAll() {
return customerRepository.findAllOrderByName();
}

public Optional<Customer> findOne(Integer id) {
return customerRepository.findById(id);
}

public Customer create(Customer customer) {
return customerRepository.save(customer);
}

public Customer update(Customer customer) {
return customerRepository.save(customer);
}

public void delete(Integer id) {
customerRepository.deleteById(id);
}
}
```
### CustomerService.java

```Java
package com.example.api;
import com.example.domain.Customer;
import com.example.service.CustomerService;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.Optional;

@RestController
@RequestMapping("api/customers")
public class CustomerRestController {
@Autowired
CustomerService customerService;

@GetMapping
List<Customer> getCustomers() {
List<Customer> customers = customerService.findAll();
return customers;
}
@GetMapping(path = "{id}")
Optional<Customer> getCustomer(@PathVariable Integer id) {
Optional<Customer> customer = customerService.findOne(id);
return customer;
}
}
```

[IT001]

追記しました。OptionalはJava8以降の書き方なので、Javaの入門書も見てみると良いかもしれません。