使用Spring Data轻松操作数据库

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作者：霜花似雪

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2020-1-6

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文章主要介绍Spring Data简介,如何使用Spring Data,Spring Data提供的相关接口, 希望对您的学习有所帮助。
本文来自于慕课网，由火龙果软件Delores编辑、推荐。

一、Spring Data简介

Spring Data官网：https://spring.io/projects/spring-data

Spring Data是Spring的一个子项目，它是为了简化数据库的操作访问而生的，为开发者提供了统一的，一致性的操作数据库的接口。

Spring Data又包含多个子项目，常用的有：

Spring Date JPA：目的是为了减少数据层的开发量，提供了操作数据库的接口。

Spring Date MongoDB：为操作MongoDB数据库提供了接口支持，在大数据层用的比较多。

Spring Date Redis：为操作Redis数据库提供了相关的接口支持。

Spring Date Solr：提供对Solr的接口支持。Solr是一个高性能，具有搜索功能，对查询性能优化的一个全文搜索引擎。

二、如何使用Spring Data

maven地址：https://mvnrepository.com/search?q=Spring+Data

在项目的pom.xml文件引入如下依赖即可：

1）JPA:

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.1.10.RELEASE</version>
</dependency>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager
</artifactId>
<version>5.4.2.Final</version>
</dependency>

（2）MongoDB

<dependency>
<groupId>org.springframework.data
</groupId>
<artifactId>spring-data-mongodb
</artifactId>
<version>2.1.10.RELEASE</version>
</dependency>

（3）Redis

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-redis</artifactId>
<version>2.1.10.RELEASE</version>
</dependency>

三、Spring Data提供的相关接口

(1) Repository：

Repository接口是Spring Data的核心接口，它不提供任何方法，是一个空接口。

我们定义的接口 xxxRepository extends Repository，表示此接口纳入spring管理，需按一定规则定义方法。

如果我们不想继承Repository接口，可以通过注解来实现同样的功能，如下：

@RepositoryDefinition(domainClass = 实体类名.class,idClass=实体类的主键封装类型.class)

Repository接口的源码如下：

package org.springframework.
data.repository;
import org.
springframework.stereotype.Indexed;

@Indexed
public interface Repository<T, ID>{}

(2)CrudRepository：

CrudRepository接口继承Repository，实现了CURD相关的方法 ,具体如图。

(3)JpaRepository

paRepository接口继承PagingAndSortingRepository，实现JPA规范相关的方法，具体如下：

(4)PagingAndSortingRepository

PagingAndSortingRepository接口继承CrudRepository,实现了分布排序相关方法。

该接口包含分页和排序功能。

带排序的查询：findAll(Sort sort)。

带排序的分页查询：findAll(Pageable pageable)。

CRUDRepository 继承Repository

PagingAndSortingRepository 继承CRUDRepository

JpaRepository 继承PagingAndSortingRepository

意味着只需继承接口JpaRepository, 便有了以上所有接口的功能。

四、实战应用

1. 项目结构

2. pom.xml文件配置

<dependencies>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java
</artifactId>
<version>8.0.11</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>

<dependency>
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-core</artifactId>
<version>1.3</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework.data
</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.1.10.RELEASE</version>
</dependency>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager
</artifactId>
<version>5.4.2.Final</version>
</dependency>
</dependencies>

3. db.properties配置：

#数据库配置信息
jdbc.driverClass=com.mysql.cj.
jdbc.Driver
jdbc.url=jdbc:mysql://
127.0.0.1:3306
/test?useSSL=false&serverTimezone=
UTC&allowPublicKeyRetrieval=true
jdbc.username=root
jdbc.password=root

4. beans.xml配置：

5. beans-new.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.spring
framework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001
/XMLSchema-instance"
xmlns:context="http://www.spring
framework.org/schema/context"
xmlns:tx="http://www.spring
framework.org/schema/tx"
xmlns:jpa="http://www.spring
framework.org/schema/data/jpa"
xsi:schemaLocation="http://www.spring
framework.org/schema/beans http://
www.springframework.org/schema/
beans/spring-beans.xsd
http://www.springframework.org/
schema/data/jpa
http://www.springframework.org/
schema/data/jpa/spring-jpa-1.8.xsd
http://www.springframework.org/
schema/tx http://www.springframework.org
/schema/tx/spring-tx-4.0.xsd
http://www.springframework.
org/schema/context
http://www.springframework.org/schema
/context/spring-context-4.0.xsd">

<context:property-placeholder
location="db.properties"/>

<bean id="dataSource"
class="org.springframework.jdbc.
datasource.DriverManagerDataSource">

<property name="driverClassName"
value="${jdbc.driverClass}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username"
value="${jdbc.username}"/>
<property name="password"
value="${jdbc.password}"/>
</bean>

<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.
LocalContainerEntityManagerFactoryBean">
<property name="dataSource"
ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.
jpa.vendor.HibernateJpaVendorAdapter"/>
</property>
<property name="packagesToScan"
value="com.lhf.spring"/>

<property name="jpaProperties">
<props>
<prop key="hibernate.ejb.naming_strategy">
org.hibernate.cfg.ImprovedNamingStrategy
</prop>
<prop key="hibernate.dialect">org.hibernate.
dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">
update</prop> 
</props>
</property>
</bean>

<bean id="transactionManager"
class="org.springframework.orm.jpa.
JpaTransactionManager">
<property name="entityManagerFactory"
ref="entityManagerFactory"/>
</bean>

<tx:annotation-driven
transaction-manager="transactionManager"/>

<jpa:repositories base-package
="com.lhf.spring" entity-manager-factory-ref="entityManagerFactory"/>

<context:component-scan
base-package="com.lhf.spring"/>

</beans>

6. EmployeeRepository.java接口

package com.lhf.spring.repository;
import com.lhf.spring.domain.Employee;
import org.springframework.data.
jpa.repository.Modifying;
import org.springframework.data.
jpa.repository.Query;
import org.springframework.data.
repository.Repository;
import org.springframework.data.
repository.RepositoryDefinition;
import org.springframework.data.
repository.query.Param;

import java.util.List;
/**
* @ClassName: EmployeeRepository
* @Description:
* @Author: liuhefei
* @Date: 2019/8/11
* @blog: https://www.imooc.com
/u/1323320/articles
**/
@RepositoryDefinition(domainClass
= Employee.class,
idClass = Integer.class)
public interface
EmployeeRepository
{ //extends Repository<Employee,Integer>{

public Employee findByName(String name);

/**
* 查询以name开头，小于age的数据
* @param name
* @param age
* @return
*/
public List<Employee>
findByNameStartingWithAndAgeLessThan
(String name, Integer age);

/**
* 查询以name结尾，小于age的数据
* @param name
* @param age
* @return
*/
public List<Employee>
findByNameEndingWithAndAgeLessThan
(String name, Integer age);

/**
* 查询多个name或小于age的数据
* @param name
* @param age
* @return
*/
public List<Employee>
findByNameInOrAgeLessThan
(List<String> name, Integer age);
/**
* 查询多个name并且小于age的数据
* @param name
* @param age
* @return
*/
public List<Employee>
findByNameInAndAgeLessThan
(List<String> name, Integer age);

/**
* 查询id最大的数据
* @return
*/
@Query("select o from Employee
o where
id=(select max(id) from Employee t1)")
public Employee getEmployeeByMaxId();

/**
* 根据name和age查询所有匹配的数据
* @param name
* @param age
* @return
*/
@Query("select o from Employee
o where o.name=?1 and o.age=?2")
public List<Employee>
queryParams1(String name, Integer age);

/**
* 根据name或age查询所有匹配的数据
* @param name
* @param age
* @return
*/
@Query("select o from Employee
o where o.name=:name or o.age=:age")
public List<Employee>
queryParams2(@Param("name")
String name, @Param("age") Integer age);
/**
* 根据name进行like查询
* @param name
* @return
*/
@Query("select o from Employee
o where o.name like %?1%")
public List<Employee>
queryLike1(String name);
@Query("select o from Employee
o where o.name like %:name%")
public List<Employee> queryLike2
(@Param("name")String name);
/**
* 查询总的记录条数
* @return
*/
@Query("select count(*) from Employee")
public long getCount();

@Query(nativeQuery = true,
value = "select count(1) from Employee")
public long getCount1();

/**
* 根据id更新年龄
* @param id
* @param age
*/
@Modifying
@Query("update Employee o set
o.age = :age where o.id = :id")
public void update(@Param("id")
Integer id, @Param("age")Integer age);
}

7. EmployeeCrudRepository.java接口：

package com.lhf.spring.repository;
import com.lhf.spring.domain.Employee;
import org.springframework.
data.repository.CrudRepository;

/**
* @ClassName: EmployeeCrudRepository
* @Description:
* @Author: liuhefei
* @Date: 2019/8/11
* @blog: https://www.imooc.com
/u/1323320/articles
**/
public interface EmployeeCrud
Repository extends CrudRepository
<Employee, Integer> {
}

8. EmployeeJpaRepository.java接口

package com.lhf.spring.repository;
import com.lhf.spring.domain.Employee;
import org.springframework.data.
jpa.repository.JpaRepository;

/**
* @ClassName: EmployeeJpaRepository
* @Description:
* @Author: liuhefei
* @Date: 2019/8/12
* @blog: https://www.imooc.com
/u/1323320/articles
**/
public interface EmployeeJpa
Repository extends JpaRepository
<Employee, Integer> {

}

9. EmployeePagingAndSortingRespsitory.java接口

package com.lhf.spring.repository;
import com.lhf.spring.domain.Employee;
import org.springframework.data.
repository.
PagingAndSortingRepository;

/**
* @ClassName: EmployeePagingAnd
SortingRespsitory
* @Description: PagingAndSorting
Repository支持分页和排序
* @Author: liuhefei
* @Date: 2019/8/11
* @blog: https://www.imooc.com
/u/1323320/articles
**/
public interface EmployeePaging
AndSortingRespsitory extends PagingAndSortingRepository<Employee,
Integer> {

}

10. EmployeeJpaSpecificationExecutorRepository.java接口

package com.lhf.spring.repository;
import com.lhf.spring.domain.Employee;
import org.springframework.data.jpa.
repository.JpaRepository;
import org.springframework.data.jpa.
repository.JpaSpecificationExecutor;

/**
* @ClassName: EmployeeJpaSpecification
ExecutorRepository
* @Description:
* @Author: liuhefei
* @Date: 2019/8/12
* @blog: https://www.imooc.com/
u/1323320/articles
**/
public interface Employee
JpaSpecificationExecutorRepository
extends JpaRepository<Employee, Integer>,
JpaSpecificationExecutor<Employee> {
}

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