SpringBoot2.0.3 集成Spring data jpa 完成增删改查的功能实现

SpringBoot框架的搭建就不在说了，文章很多，jpa支持OneToOne,OneToMany,ManyToOne,ManyToMany的配置，在开发上相当效率，另外Jpa在没有实体的情况下执行Sql查询，不需要映射，非常强大。

下面介绍一下jpa结合java1.8的一些函数编程思想。

1.首先编写一个BaseRepository

@NoRepositoryBean
public interface BaseRepository extends Repository {

	Optional findOne(ID id);
	
	 S save(S entity);

	Optional findById(ID primaryKey);

	Iterable findAll();

	long count();

	void delete(T entity);

	boolean existsById(ID primaryKey);
}

2，编写实体类

@Entity(name = "Student")   
public class Student implements Serializable{    
	private static final long serialVersionUID = 5537592547914489373L;	
	@Id  
    @GeneratedValue  
    private Integer id;
    private String name; 
    private Integer age;  
    private String sex;  
    private String phone; 
    private String address;

3,编写DAO层

public interface StudentRepository extends BaseRepository{

	List findByNameLike(String surname);

	List findAll(Specification specification);

	Optional findOne(Integer id);

	Optional findByName(String name);

	@Query("SELECT id,address,age,classNo,name,phoneNum,sex FROM Student ")
	Stream streamAllStudents();

	@Async
	CompletableFuture> readAllBy();
	
}

4，Service层

@Service
public class StudentService {

	@Autowired
	private StudentRepository studentRepository;

	public List findAll() {
		return studentRepository.findAll(null);
	}

	public Student getStudent(int id) {
		Optional findOne = studentRepository.findOne(id);
		Student student = findOne.get();
		return student;
	}

	@Transactional
	public List streamAllStudents() {
		List studentList;
		try (Stream customers = studentRepository.streamAllStudents()) {
			studentList = customers.collect(Collectors.toList());
		}
		return studentList;
	}

	public List readAllBy() throws InterruptedException, ExecutionException {
		CompletableFuture> future = studentRepository.readAllBy();
		CompletableFuture.supplyAsync(this::streamAllStudents);
		return future.get();
	}

}

5，WEB层

@RestController
@RequestMapping("/springboot_jpa")
public class StudentWeb {

	@Autowired
	private StudentService studentService;

	// 找出所有的学生
	@RequestMapping("/student/findAll")
	public List findAll() {
		return studentService.findAll();
	}

	@RequestMapping("/student/jdk8text")
	private Student getOne() {
		Student student = studentService.getStudent(1);
		return student;
	}

	/**
	 * 返回的是集合中的对象
	 * 
	 * @return
	 * @Description:
	 * @author Bern_Liu
	 * @version 创建时间：2018年6月22日 下午2:09:18
	 */
	@RequestMapping("/student/getListStudent")
	private List getListStudent() {
		List totalStudent = studentService.streamAllStudents();
		return totalStudent;
	}

	/**
	 * 返回的是JSON对象 name:xxx
	 * 
	 * @return
	 * @Description:
	 * @author Bern_Liu
	 * @version 创建时间：2018年6月22日 下午2:09:18
	 */
	@RequestMapping("/student/readAllBy")
	private List readAllBy() throws InterruptedException, ExecutionException {
		return studentService.readAllBy();
	}