SpringDataJpa

前言：

它是JPA规范的再次封装抽象，底层还是使用了Hibernate的JPA技术实现，引用JPQL的查询语句 ，是属于Spring的生成体系中的一部分。

SpringDataJpa使用起来比较方便，加快了开发的速度，使开发人员不需要关心和配置更多的东西。

SpringDataJpa上手简单，开发效率高，对对象的支持非常好，还十分的灵活。

使用方法(开发工具：idea):

1、导包 pom.xml配置

${org.springframework.version}:这是为了统一更换同种类型的包
有些包是多余的，

1、    <dependencies>
  <!-- Spring的支持包 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>${org.springframework.version}</version>
    <scope>test</scope>
  </dependency>
  <!-- 引入web前端的支持 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${org.springframework.version}</version>
  </dependency>
  <!-- SpringMCV上传需要用到io包-->
  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-io</artifactId>
    <version>1.3.2</version>
  </dependency>
  <!-- 文件上传用到的包 -->
  <dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.2.2</version>
  </dependency>
  <!-- SpringMVC的json支持包 -->
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>${com.fasterxml.jackson.version}</version>
  </dependency>
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>${com.fasterxml.jackson.version}</version>
  </dependency>
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>${com.fasterxml.jackson.version}</version>
  </dependency>
  <!-- hibernate的支持包 -->
  <dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>${org.hibernate.version}</version>
  </dependency>
  <dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>${org.hibernate.version}</version>
  </dependency>
  <!-- SpringData的支持包 -->
  <dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>${spring-data-jpa.version}</version>
  </dependency>
  <!-- SpringData的擴展包 -->
  <dependency>
    <groupId>com.github.wenhao</groupId>
    <artifactId>jpa-spec</artifactId>
    <version>3.1.1</version>
    <!-- 把所有的依賴都去掉 -->
    <exclusions>
      <exclusion>
        <groupId>*</groupId>
        <artifactId>*</artifactId>
      </exclusion>
    </exclusions>
  </dependency>

  <dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>1.2.2</version>
  </dependency>

  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.6</version>
  </dependency>

  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.5</version>
  </dependency>
  <!-- 測試包 -->
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1.0</version>
    <!-- 这个scope 只能作用在编译和测试时，同时没有传递性。表示在运行的时候不添加此jar文件 -->
    <scope>provided</scope>
  </dependency>
  <!-- 日志文件 -->
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>${org.slf4j.version}</version>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>${org.slf4j.version}</version>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.14</version>
  </dependency>
  <!-- 代码生成器模版技术 -->
  <dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.6</version>
  </dependency>
  <!-- shiro的支持包 -->
  <dependency>
    <groupId>org.apache.shiro</groupId>
    <artifactId>shiro-all</artifactId>
    <version>1.4.0</version>
    <type>pom</type>
  </dependency>
  <!-- shiro与Spring的集成包 -->
  <dependency>
    <groupId>org.apache.shiro</groupId>
    <artifactId>shiro-spring</artifactId>
    <version>1.4.0</version>
  </dependency>
  <!-- poi支持的jar包 -->
  <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.11</version>
  </dependency>
  <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.11</version>
  </dependency>
  <!-- 图片压缩功能 -->
  <!-- 缩略图 -->
  <dependency>
    <groupId>net.coobird</groupId>
    <artifactId>thumbnailator</artifactId>
    <version>0.4.6</version>
  </dependency>
  <!-- 定时调度 -->
  <dependency>
    <groupId>quartz</groupId>
    <artifactId>quartz</artifactId>
    <version>1.5.2</version>
  </dependency>
  <!-- 邮件支持 -->
  <dependency>
    <groupId>javax.mail</groupId>
    <artifactId>mail</artifactId>
    <version>1.4.1</version>
  </dependency>
</dependencies>

2、SpringDataJpa基本配置，配置applicationContext.xml

<?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/context
        http://www.springframework.org/schema/context/spring-context.xsd
      http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd
        http://www.springframework.org/schema/data/jpa
        http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
        ">

    <!--加载properties文件-->
    <context:property-placeholder location="classpath:jdbc.properties"/>
    <!--配置连接池-->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <!--maxActive: 最大连接数量 -->
        <property name="maxActive" value="150" />
        <!--minIdle: 最小空闲连接 -->
        <property name="minIdle" value="5" />
        <!--maxIdle: 最大空闲连接 -->
        <property name="maxIdle" value="20" />
        <!--initialSize: 初始化连接 -->
        <property name="initialSize" value="30" />
        <!-- 用来配置数据库断开后自动连接的 -->
        <!-- 连接被泄露时是否打印 -->
        <property name="logAbandoned" value="true" />
        <!--removeAbandoned: 是否自动回收超时连接 -->
        <property name="removeAbandoned" value="true" />
        <!--removeAbandonedTimeout: 超时时间(以秒数为单位) -->
        <property name="removeAbandonedTimeout" value="10" />
        <!--maxWait: 超时等待时间以毫秒为单位 1000等于60秒 -->
        <property name="maxWait" value="1000" />
        <!-- 在空闲连接回收器线程运行期间休眠的时间值,以毫秒为单位. -->
        <property name="timeBetweenEvictionRunsMillis" value="10000" />
        <!-- 在每次空闲连接回收器线程(如果有)运行时检查的连接数量 -->
        <property name="numTestsPerEvictionRun" value="10" />
        <!-- 1000 * 60 * 30 连接在池中保持空闲而不被空闲连接回收器线程 -->
        <property name="minEvictableIdleTimeMillis" value="10000" />
        <property name="validationQuery" value="SELECT NOW() FROM DUAL" />
    </bean>
    <!--配置entityManagerFactory-->
    <bean id="myEmf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <!--注入dataSource-->
        <property name="dataSource" ref="dataSource"/>
        <!--配置扫描的包,只认识jpa的注解-->
        <property name="packagesToScan" value="cn.king.aisell.domain"/>
        <!--配置jpa的实现-->
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <!--是否显示SQL-->
                <property name="showSql" value="true"/>
                <!--建表策略-->
                <property name="generateDdl" value="false"/>
                <!--方言-->
                <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect"/>
            </bean>
        </property>
    </bean>
    <!--配置事务-->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="myEmf"/>
    </bean>
    <!--开启事务管理 transaction-manager="transactionManager"可以不写，默认transactionManager-->
    <tx:annotation-driven transaction-manager="transactionManager"/>
    <!--配置扫描-->
    <context:component-scan base-package="cn.king.aisell.service"/>
    <!--配置springDataJpa扫描-->
    <jpa:repositories base-package="cn.king.aisell.repository"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="myEmf"/>
</beans>

3、原来dao层改成repository(命名规范)

4、完成相应的CRUD(继承JpaRepository和JpaSpecificationExecutor)

//JpaRepository<需要操作的domain,与之对应的主键类型>
//JpaSpecificationExecutor<需要操作的domain>:让模糊查询和分页相结合
public interface EmployeeRepository
        extends JpaRepository<Employee,Long> ,
        JpaSpecificationExecutor<Employee> {
}