这里就滤过Spring Data JPA我的项目部署，不分明的能够看一下开源我的项目AutoAdmin。
Entity(表实体类)
一个表对应一个实体类，这里以AutoAdmin的sys_user表为例：
import cn.songhaiqing.autoadmin.base.BaseEntity;import org.hibernate.annotations.Where;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.Table;@Entity@Table(name = "sys_user")@Where(clause = "deleted=0")public class SysUser extends BaseEntity { // 账号 @Column(name = "account") private String account; // 明码 @Column(name = "password") private String password; // 姓名 @Column(name = "name") private String name; // 明码加密盐 @Column(name = "salt") private String salt; public String getAccount() { return account; } public void setAccount(String account) { this.account = account; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSalt() { return salt; } public void setSalt(String salt) { this.salt = salt; }}备注
- @Table注解：写表名，如果表是刚好应用驼峰命名的话能够不写，倡议写上。
- @Where ：查问该表时会主动加个的条件，用来做软删除过滤是十分好的抉择，然而在@ManyToOne get该实体时如果数据已删除就会有问题，留神区别应用。
- @Column 字段申明，能够写在不同的地位，但集体习惯写在字段上一行。属性名能够和数据库表字段名不一样。
BaseEntity
实体类继承了BaseEntity，该类写一些通用的字段，像ID、创立工夫、更新工夫、删除标注等。
import javax.persistence.*;import java.util.Date;@MappedSuperclasspublic class BaseEntity { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @Column(name = "create_time", nullable = false,updatable = false) private Date createTime = new Date(); @Column(name = "update_time", nullable = false) private Date updateTime = new Date(); @Column(name = "deleted", nullable = false) private boolean deleted = false; public Date getCreateTime() { return createTime; } public Date getUpdateTime() { return updateTime; } public void setUpdateTime(Date updateTime) { this.updateTime = updateTime; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public void setCreateTime(Date createTime) { this.createTime = createTime; } public boolean isDeleted() { return deleted; } public void setDeleted(boolean deleted) { this.deleted = deleted; }}备注
* @Id @GeneratedValue(strategy = GenerationType.AUTO) ID 自增
* 默认值：间接给变量设置初始值就能够了，create_time（创立工夫）有点不一样，因为我不想当前扭转值，因为须要设置updatable = false。
Repository(表操作接口)
有人习惯叫DAO或其余，JPA很重要的中央，应用JPA的语法简略间接的代替了大部分SQL。
示例
import cn.songhaiqing.autoadmin.entity.SysUser;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.data.jpa.repository.JpaSpecificationExecutor;import org.springframework.stereotype.Repository;@Repositorypublic interface SysUserRepository extends JpaRepository<SysUser, Long>,JpaSpecificationExecutor<SysUser> { SysUser findByAccount(String account); long countByAccount(String account); long countByAccountAndIdNot(String account, Long id);}查问
依据单查问（一条后果）
SysUser findByAccount(String account);须要确保返回的后果最多只有一条，否则会报错
依据单查问（多条后果）
List<SysUser> findByAccount(String account);多条件查问
SysUser findByAccountAndPassword(String account, String password);查问第一条
SysUser findFirstByAccount(String account);查问前10条
SysUser findTop10ByAccount(String account);排序
SysUser findTop10ByAccount(String account);JPA语法
| Keyword | Sample | JPQL snippet |
|---|---|---|
| And | findByLastnameAndFirstname | … where x.lastname = ?1 and x.firstname = ?2 |
| Or | findByLastnameOrFirstname | … where x.lastname = ?1 or x.firstname = ?2 |
| Is,Equals | findByFirstname | … where x.firstname = ?1 |
| findByFirstnameIs | ||
| findByFirstnameEquals | ||
| Between | findByStartDateBetween | … where x.startDate between ?1 and ?2 |
| LessThan | findByAgeLessThan | … where x.age < ?1 |
| LessThanEqual | findByAgeLessThanEqual | … where x.age <= ?1 |
| GreaterThan | findByAgeGreaterThan | … where x.age > ?1 |
| GreaterThanEqual | findByAgeGreaterThanEqual | … where x.age >= ?1 |
| After | findByStartDateAfter | … where x.startDate > ?1 |
| Before | findByStartDateBefore | … where x.startDate < ?1 |
| IsNull | findByAgeIsNull | … where x.age is null |
| IsNotNull,NotNull | findByAge(Is)NotNull | … where x.age not null |
| Like | findByFirstnameLike | … where x.firstname like ?1 |
| NotLike | findByFirstnameNotLike | … where x.firstname not like ?1 |
| StartingWith | findByFirstnameStartingWith | … where x.firstname like ?1(parameter bound with appended %) |
| EndingWith | findByFirstnameEndingWith | … where x.firstname like ?1(parameter bound with prepended %) |
| Containing | findByFirstnameContaining | … where x.firstname like ?1(parameter bound wrapped in %) |
| OrderBy | findByAgeOrderByLastnameDesc | … where x.age = ?1 order by x.lastname desc |
| Not | findByLastnameNot | … where x.lastname <> ?1 |
| In | findByAgeIn(Collection ages) | … where x.age in ?1 |
| NotIn | findByAgeNotIn(Collection ages) | … where x.age not in ?1 |
| TRUE | findByActiveTrue() | … where x.active = true |
| FALSE | findByActiveFalse() | … where x.active = false |
| IgnoreCase | findByFirstnameIgnoreCase | … where UPPER(x.firstame) = UPPER(?1) |
分页简单查问
示例
List<Sort.Order> orders = new ArrayList<>();orders.add(new Sort.Order(Sort.Direction.DESC,"id"));Sort sort = new Sort(orders);Page<SysUser> page = sysUserRepository.findAll(new Specification<SysUser>(){ @Override public Predicate toPredicate(Root<SysUser> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) { List<Predicate> predicate = new ArrayList<>(); // 此处增加过滤条件 Predicate[] pre = new Predicate[predicate.size()]; return criteriaQuery.where(predicate.toArray(pre)).getRestriction(); }},new PageRequest(query.getPage() - 1, query.getLimit(),sort));BaseResponseList<SysUserViewModel> result = new BaseResponseList<>();result.setCount(page.getTotalElements());List<SysUserViewModel> models = new ArrayList<>();for (SysUser sysUser : page.getContent()) { SysUserViewModel model = new SysUserViewModel(); model.setId(sysUser.getId()); model.setAccount(sysUser.getAccount()); model.setName(sysUser.getName()); models.add(model);}result.setData(models);return result;此例中联合了分页、排序、过滤性能。
参考
- Spring Data JPA官网文档