3.2 使用Spring Data JPA 持久化数据
3.2 使用Spring Data JPA 持久化数据
Spring Data JPA - 针对关系数据库的持久化Spring Data Mongo - 针对Mongo 文档数据库的持久化Spring Data Neo4j - 针对Neo4j 图形数据库的持久化Spring Data Redis - 针对Redis 键值存储的持久化Spring Data Cassandra - 针对Cassandra 数据库的持久化
为了了解
3.2.1 添加Spring Data JPA 到数据库中
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
如果想使用不同的
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<exclusions>
<exclusion>
<artifactId>hibernate-entitymanager</artifactId>
<groupId>org.hibernate</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.eclipse.persistence</groupId>
<artifactId>eclipselink</artifactId>
<version>2.5.2</version>
</dependency>
请注意，根据对
3.2.2 注解域作为实体
很快就会看到，在创建存储库方面，
package tacos;
import javax.persistence.Entity;
import javax.persistence.Id;
import lombok.AccessLevel;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.RequiredArgsConstructor;
@Data
@RequiredArgsConstructor
@NoArgsConstructor(access=AccessLevel.PRIVATE, force=true)
@Entity
public class Ingredient {
@Id
private final String id;
private final String name;
private final Type type;
public static enum Type {
WRAP, PROTEIN, VEGGIES, CHEESE, SAUCE
}
}
为了将其声明为
除了特定于
还添加了一个
现在让我们转到
package tacos;
import java.util.Date;
import java.util.List;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.PrePersist;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import lombok.Data;
@Data
@Entity
public class Taco {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
@NotNull
@Size(min=5, message="Name must be at least 5 characters long")
private String name;
private Date createdAt;
@ManyToMany(targetEntity=Ingredient.class)
@Size(min=1, message="You must choose at least 1 ingredient")
private List<Ingredient> ingredients;
@PrePersist
void createdAt() {
this.createdAt = new Date();
}
}
与
要声明
还有一个新方法
package tacos;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.PrePersist;
import javax.persistence.Table;
import javax.validation.constraints.Digits;
import javax.validation.constraints.Pattern;
import org.hibernate.validator.constraints.CreditCardNumber;
import org.hibernate.validator.constraints.NotBlank;
import lombok.Data;
@Data
@Entity
@Table(name="Taco_Order")
public class Order implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
private Date placedAt;
...
@ManyToMany(targetEntity=Taco.class)
private List<Taco> tacos = new ArrayList<>();
public void addDesign(Taco design) {
this.tacos.add(design);
}
@PrePersist
void placedAt() {
this.placedAt = new Date();
}
}
对
尽管可以在任何实体上使用这个注解，但它对于
3.2.3 声明JPA repository
在存储库的
package tacos.data;
import org.springframework.data.repository.CrudRepository;
import tacos.Ingredient;
public interface IngredientRepository extends CrudRepository<Ingredient, String> {
}
也可以这样定义
package tacos.data;
import org.springframework.data.repository.CrudRepository;
import tacos.Taco;
public interface TacoRepository extends CrudRepository<Taco, Long> {
}
package tacos.data;
import org.springframework.data.repository.CrudRepository;
import tacos.Order;
public interface OrderRepository extends CrudRepository<Order, Long> {
}
现在有了这三个
3.2.4 自定义JPA repository
想象一下，除了
List<Order> findByDeliveryZip(String deliveryZip);
在生成
让我们考虑另一个更复杂的例子。假设需要查询在给定日期范围内投递给指定邮政编码的所有订单。在这种情况下，当添加到
List<Order> readOrdersByDeliveryZipAndPlacedAtBetween(
String deliveryZip, Date startDate, Date endDate);
图
图
尽管该方法的主语是可选的，但在这里它表示
谓词跟在方法名中的
除了一个隐式的
- IsAfter, After, IsGreaterThan, GreaterThan
- IsGreaterThanEqual, GreaterThanEqual
- IsBefore, Before, IsLessThan, LessThan
- IsLessThanEqual, LessThanEqual
- IsBetween, Between
- IsNull, Null
- IsNotNull, NotNull
- IsIn, In
- IsNotIn, NotIn
- IsStartingWith, StartingWith, StartsWith
- IsEndingWith, EndingWith, EndsWith
- IsContaining, Containing, Contains
- IsLike, Like
- IsNotLike, NotLike
- IsTrue, True
- IsFalse, False
- Is, Equals
- IsNot, Not
- IgnoringCase, IgnoresCase
作为
List<Order> findByDeliveryToAndDeliveryCityAllIgnoresCase(
String deliveryTo, String deliveryCity);
最后，还可以将
List<Order> findByDeliveryCityOrderByDeliveryTo(String city);
虽然命名约定对于相对简单的查询很有用，但是对于更复杂的查询，不需要太多的想象就可以看出方法名称可能会失控。在这种情况下，可以随意将方法命名为任何想要的名称，并使用
@Query("Order o where o.deliveryCity='Seattle'")
List<Order> readOrdersDeliveredInSeattle();
在这个