Spring Data 項目的目的是為了簡化構建基於 Spring 框架應用的數據訪問計數，包括非關系數據庫、Map-Reduce 框架、雲數據服務等等，SpringData JPA是簡化創建 JPA 數據訪問層和跨存儲的持久層功能，通過一個接口的繼承即可實現簡單的CRUD。

　　數據庫的連接與項目的構建不說了，可以參考：springboot實戰SpringDataJPA。我采用的是eclipse構建的普通的springboot項目。

一、創建表與實體類映射

@Entity
@Table(name = "student")
public class Student implements Serializable {
	@Id
	// id自動生成
	@GeneratedValue
	@Column(name = "id")
	private Long id;
	@Column(name = "name")
	private String name;
	@Column(name = "clas")
	private String clas;

	@Column(name = "interest")
	private String interest;

    // 省略了getter(),setter()方法　

二、創建StudentMapper 繼承JpaRepository<Student, Long>，第一個參數是實體，第二個參數是主鍵的類型

public interface StudentMapper extends JpaRepository<Student, Long> {
	// int queryCount();
	// 自定義的方法實現findAll
	@Query(value = "select * from student where id < ?1", nativeQuery = true)
	public List<Student> findAll(Long id);
}

三、Controller內的代碼如下：

@Resource
	private FirstPageService firstPageService;

	@RequestMapping(value = "/", method = RequestMethod.GET)
	@Fooish(tags = { "this_is_method" })
	String home() {
		return firstPageService.getString();
	}

	@RequestMapping(value = "/add", method = RequestMethod.GET)
	String addStudent(Student student) {
		return firstPageService.addStudent(student);
	}

	@RequestMapping(value = "/delete", method = RequestMethod.GET)
	String deleteStudent(Long id) {
		return firstPageService.deleteStudent(id);
	}

	@RequestMapping(value = "/update", method = RequestMethod.GET)
	String updateStudent(Student student) {
		return firstPageService.updateStudent(student);
	}

	@RequestMapping(value = "/list", method = RequestMethod.GET)
	List<Student> listStudent() {
		return firstPageService.listStudent();
	}

	// 采用的是自定義的方法
	@RequestMapping(value = "/list2", method = RequestMethod.GET)
	List<Student> list2Student(Long id) {
		return firstPageService.nativeQuery(id);
	}

	// 分頁查詢
	@RequestMapping(value = "/pageRequest", method = RequestMethod.GET)
	List<Student> pageRequest() {

		return firstPageService.pageRequest();
	}

	// 分頁與排序查詢
	@RequestMapping(value = "/pageAndSortRequest", method = RequestMethod.GET)
	List<Student> pageAndSortRequest() {

		return firstPageService.pageAndSortRequest();
	}

四、服務層firstPageService代碼如下：

@Resource
	private StudentMapper studentMapper;

	public String getString() {

		// return name;
		// int a = studentMapper.queryCount();
		// return a + "";
		return "Hellow World!";
	}

	public String addStudent(Student stu) {
		studentMapper.save(stu);
		return "添加成功";
	}

	public String deleteStudent(Long id) {
		studentMapper.delete(id);
		return "刪除成功";
	}

	public String updateStudent(Student stu) {
		// 如果有就更新，沒有就添加
		studentMapper.save(stu);
		return "更新成功";
	}

	public List<Student> listStudent() {

		return studentMapper.findAll();
	}

	public List<Student> nativeQuery(Long id) {
		return studentMapper.findAll(id);
	}

　　　　// 分頁查詢
	public List<Student> pageRequest() {
		PageRequest pageRequest = new PageRequest(1, 3);
		Page<Student> stuPage = studentMapper.findAll(pageRequest);
		List<Student> stuList = stuPage.getContent();
		return stuList;
	}

　　　　// 分頁與排序
	public List<Student> pageAndSortRequest() {
		Sort sort1 = new Sort(Sort.Direction.DESC, "id");
		Sort sort2 = new Sort(Sort.Direction.ASC, "name");
		// 把兩個排序的條件取取與
		Sort sort = sort1.and(sort2);
		PageRequest pageRequest = new PageRequest(1, 2, sort);
		Page<Student> stuPage = studentMapper.findAll(pageRequest);
		List<Student> stuList = stuPage.getContent();
		return stuList;
	}

通過源碼的繼承與實現關系可以看出，JpaRepository接口繼承了PagingAndSortingRepository,QueryByExampleExecutor兩個接口，PagingAndSortingRepository接口繼承了CrudRepository。CrudRepository中包含了簡單的數據庫增，刪，改，查，這四個操作還是比較簡單的，下面主要介紹分頁與排序；

下面的是PagingAndSortingRepository的源碼：

public interface PagingAndSortingRepository extends CrudRepository {

	public abstract Iterable findAll(Sort sort);

	public abstract Page findAll(Pageable pageable);
}

這個接口提供了分頁與排序的基本方法，想要實現分頁查詢，要實現Pageable接口，而PageRequest是該接口的一個實現類，該類的構造方法：

    // 單純的分頁
　　　　public PageRequest(int page, int size) {
		this(page, size, null);
	}

	public transient PageRequest(int page, int size, Sort.Direction direction,
			String properties[]) {
		this(page, size, new Sort(direction, properties));
	}
　　　　　　// 分頁與排序，要實現Sort類
	public PageRequest(int page, int size, Sort sort) {
		super(page, size);
		this.sort = sort;
	}

五、按照id倒序，name順序,查詢第二頁，每頁顯示兩個的查詢結果：

SpringData JPA實現CRUD,分頁與多參數排序