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Spring Data JPA

用來簡化創建 JPA 數據訪問層和跨存儲的持久層功能。

官網文檔連接

http://docs.spring.io/spring-data/jpa/docs/current/reference/html/

Spring Data JPA提供的接口

• Repository：最頂層的接口，是一個空的接口，目的是為了統一所有Repository的類型，且能讓組件掃描的時候自動識別
• CrudRepository ：是Repository的子接口，提供CRUD的功能
• PagingAndSortingRepository：是CrudRepository的子接口，添加分頁和排序的功能
• JpaRepository：是PagingAndSortingRepository的子接口，增加了一些實用的功能，比如：批量操作等
• JpaSpecificationExecutor：用來做負責查詢的接口
• Specification：是Spring Data JPA提供的一個查詢規范，要做復雜的查詢，只需圍繞這個規范來設置查詢條件即可
  

Repository接口查詢規則

關鍵字案例效果

And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstname,findByFirstnameIs,findByFirstnameEquals	… where x.firstname = ?1
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 age)	… 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)

項目圖片

pom.xml

-只需要在pom.xml引入需要的數據庫配置，就會自動訪問此數據庫，如果需要配置其他數據庫，可以在application.properties進行添加
-默認使用org.apache.tomcat.jdbc.pool.DataSource創建連接池

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.jege.spring.boot</groupId><artifactId>spring-boot-data-jpa</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>spring-boot-data-jpa</name><url>http://maven.apache.org</url><!-- 公共spring-boot配置，下面依賴jar文件不用在寫版本號 --><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.4.1.RELEASE</version><relativePath /></parent><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><java.version>1.8</java.version></properties><dependencies><!-- 持久層 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><!-- h2內存數據庫 --><dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><build><finalName>spring-boot-data-jpa</finalName><plugins><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><configuration><source>${java.version}</source><target>${java.version}</target></configuration></plugin></plugins></build> </project>

模型對象User

package com.jege.spring.boot.data.jpa.entity;import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table;/*** @author JE哥* @email 1272434821@qq.com* @description:jpa模型對象*/ @Entity @Table(name = "t_user") public class User {@Id@GeneratedValueprivate Long id;private String name;private Integer age;public User() {}public User(String name, Integer age) {this.name = name;this.age = age;}}

持久層UserRepository

package com.jege.spring.boot.data.jpa.repository;import java.util.List;import org.springframework.data.jpa.repository.JpaRepository;import com.jege.spring.boot.data.jpa.entity.User;/*** @author JE哥* @email 1272434821@qq.com* @description:持久層接口，由spring自動生成其實現*/ public interface UserRepository extends JpaRepository<User, Long> {List<User> findByNameLike(String name);}

啟動類Application

package com.jege.spring.boot;import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;/*** @author JE哥* @email 1272434821@qq.com* @description:spring boot 啟動類*/@SpringBootApplication public class Application {public static void main(String[] args) {SpringApplication.run(Application.class, args);}}

配置文件application.properties

## JPA Settings spring.jpa.generate-ddl: true spring.jpa.show-sql: true spring.jpa.hibernate.ddl-auto: create spring.jpa.properties.hibernate.format_sql: false

測試類UserRepositoryTest

package com.jege.spring.boot.data.jpa;import static org.assertj.core.api.Assertions.assertThat;import org.junit.After; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;import com.jege.spring.boot.data.jpa.entity.User; import com.jege.spring.boot.data.jpa.repository.UserRepository;/*** @author JE哥* @email 1272434821@qq.com* @description:*/ @RunWith(SpringJUnit4ClassRunner.class) @SpringBootTest() public class UserRepositoryTest {@AutowiredUserRepository userRepository;// 打印出class com.sun.proxy.$Proxy66表示spring注入通過jdk動態代理獲取接口的子類@Testpublic void proxy() throws Exception {System.out.println(userRepository.getClass());}@Testpublic void save() throws Exception {for (int i = 0; i < 10; i++) {User user = new User("jege" + i, 25 + i);userRepository.save(user);}}@Testpublic void all() throws Exception {save();assertThat(userRepository.findAll()).hasSize(10);}@Testpublic void findByName() throws Exception {save();assertThat(userRepository.findByNameLike("jege%")).hasSize(10);}@Afterpublic void destroy() throws Exception {userRepository.deleteAll();}}

源碼地址

https://github.com/je-ge/spring-boot

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