SpringData-jpa的基本使用

落日映苍穹つ 2022-04-15 04:08 305阅读 0赞

#  1.概述 #

JPA Spring Data : 致力于减少数据访问层 (DAO) 的开发量. 开发者唯一要做的，就只是声明持久层的接口，其他都交给 Spring Data JPA 来帮你完成！

# 2.spring整合jpa #

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xmlns:context="http://www.springframework.org/schema/context"
    	xmlns:tx="http://www.springframework.org/schema/tx"
    	xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    	xsi:schemaLocation="http://www.springframework.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-1.3.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:component-scan base-package="com.atguigu.springdata"></context:component-scan>
    
    	
    	<context:property-placeholder location="classpath:db.properties"/>
    
    	<bean id="dataSource"
    		class="com.mchange.v2.c3p0.ComboPooledDataSource">
    		<property name="user" value="${jdbc.user}"></property>
    		<property name="password" value="${jdbc.password}"></property>	
    		<property name="driverClass" value="${jdbc.driverClass}"></property>
    		<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
    		
    		
    	</bean>
    
    	
    	<bean id="entityManagerFactory" 
    		class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    		<property name="dataSource" ref="dataSource"></property>
    		<property name="jpaVendorAdapter">
    			<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>
    		</property>
    		<property name="packagesToScan" value="com.atguigu.springdata"></property>
    		<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"></property>	
    	</bean>
    
    	
    	<tx:annotation-driven transaction-manager="transactionManager"/>
    
    	
    	
    	
    	<jpa:repositories base-package="com.atguigu.springdata"
    		entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>
    
    </beans>

# 3.介绍几个接口 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70][]

# 4.介绍Repository的接口使用 #

1.声明一个接口，继承改接口![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 1][]

2.调用

![20181121125552269.png][]

3.如果方法名不按要求，会报的异常

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 2][]

4.介绍方法起名的时候需要的注意点

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 3][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 4][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 5][]

#      5.查询流程分析 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 6][]

# 5.使用@query查询 #

1.使用@Query好处

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 7][]

2.案例：传入多个参数

![20181121175552864.png][]

3.模糊查询

![20181121175642137.png][]

4.使用原生本地sql

![20181121175806196.png][]

5.@Modifying:完成更新操作

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 8][]

# 6.CrudRepository 接口 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 9][]

# 7.PagingAndSortingRepository接口 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 10][]

@Test
    	public void testSortAndPAge() {
    		
    		PersonRepsotory repsotory = ctx.getBean(PersonRepsotory.class);
    		int pageNo = 1;//起始页，从零开始，即第二页
    		int pageSize = 5;
    		//传递需要排序的字段和方式
    		Order orders1 = new Order(Direction.DESC,"id");
    		Order order2 = new Order(Direction.ASC, "email");
    		//设置排序，可以是一个可变参
    		Sort sort = new Sort(orders1,order2);
    		PageRequest pageRequest = new PageRequest(pageNo, pageSize,sort);
    		Page<Person> page = repsotory.findAll(pageRequest);
    		System.out.println("总记录数: " + page.getTotalElements());
    		System.out.println("当前第几页: " + (page.getNumber() + 1));
    		System.out.println("总页数: " + page.getTotalPages());
    		System.out.println("当前页面的 List: " + page.getContent());
    		System.out.println("当前页面的记录数: " + page.getNumberOfElements());
    	}
    
    
    }

# 8.JpaRepository接口 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 11][]、

9.JpaSpecificationExecutor接口

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 12][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L29sZHNoYXVp_size_16_color_FFFFFF_t_70 13][]

# 总结：由于每天需要上班，我只能在工作之余敲下jpa，里面的所有的代码都是我自己一点点敲出来的，希望对刚使用jpa的同事有所帮助，由于现在时间比较少，只能写点操作类的文章，后期会有更多的原理源码的文章和大家见面 #

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