SpringDataJpa的使用

1.创建一个jar工程，添加下面的依赖

 <properties>
        <spring.version>5.0.2.RELEASE</spring.version>
        <hibernate.version>5.0.7.Final</hibernate.version>
        <slf4j.version>1.6.6</slf4j.version>
        <log4j.version>1.2.12</log4j.version>
        <c3p0.version>0.9.1.2</c3p0.version>
        <mysql.version>5.1.6</mysql.version>
    </properties>

    <dependencies>
        <!-- junit单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- spring beg -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.6.8</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- spring对orm框架的支持包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- spring end -->

        <!-- hibernate beg -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>5.2.1.Final</version>
        </dependency>
        <!-- hibernate end -->

        <!-- c3p0 beg -->
        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>${c3p0.version}</version>
        </dependency>
        <!-- c3p0 end -->

        <!-- log end -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- log end -->


        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>

        <!-- spring data jpa 的座标-->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.9.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- el beg 使用spring data jpa 必须引入 -->
        <dependency>
            <groupId>javax.el</groupId>
            <artifactId>javax.el-api</artifactId>
            <version>2.2.4</version>
        </dependency>

        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>javax.el</artifactId>
            <version>2.2.4</version>
        </dependency>
        <!-- el end -->

		<!-- jdk9加入 -->
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-core</artifactId>
            <version>2.3.0</version>
        </dependency>

        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.0</version>
        </dependency>



    </dependencies>

2.创建一个配置文件applicationContext.xml，加入以下代码

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:task="http://www.springframework.org/schema/task"
       xsi:schemaLocation="
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.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">

        <context:component-scan base-package="com.baidu" />
        <!--配置实体类管理器工厂-->
        <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="dataSource" ref="dataSource"/>
            <!--配置实现Jpa的厂商-->
            <property name="persistenceProvider">
                <bean class="org.hibernate.jpa.HibernatePersistenceProvider"/>
            </property>
            <!--配置实体类所在的包-->
            <property name="packagesToScan" value="com.baidu.pojo"/>

            <!--jpa的供应商适配器 -->
            <property name="jpaVendorAdapter">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                    <!--配置是否自动创建数据库表 -->
                    <property name="generateDdl" value="false" />
                    <!--指定数据库类型 -->
                    <property name="database" value="MYSQL" />
                    <!--数据库方言：支持的特有语法 -->
                    <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                    <!--是否显示sql -->
                    <property name="showSql" value="true" />
                </bean>
            </property>

            <!--jpa的方言 ：高级的特性 -->
            <property name="jpaDialect" >
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
            </property>

            <property name="jpaProperties" >
                <props>
                 	<!--
						update:没有表则创建表
						create:删除表再创建表
					 -->
                    <prop key="hibernate.hbm2ddl.auto">update</prop>
                </props>
            </property>

        </bean>

    <!--2.创建数据库连接池 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="user" value="root"/>
        <property name="password" value="root"/>
        <property name="jdbcUrl" value="jdbc:mysql:///jpa" />
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
    </bean>

    <!--配置dao所在的位置，创建代理对象-->
    <jpa:repositories base-package="com.baidu.dao"
                      transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory"/>

    <!--创建事务管理器-->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <!--开启注解事务-->
    <tx:annotation-driven/>

</beans>

3.创建实体类

package com.baidu.pojo;

import javax.persistence.*;

@Entity    //表示此类是实体类
@Table(name = "cst_customer")    //配置数据库表名
public class Customer {


    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)  //主键生成策略，枚举类型，其它的点进去看
    @Column(name = "cust_id") //对应数据库的字段，如果不配则使用属性名当作字段名
    private Long custId; //客户的主键

    @Column(name = "cust_name")
    private String custName;//客户名称

    @Column(name="cust_source")
    private String custSource;//客户来源

    @Column(name="cust_level")
    private String custLevel;//客户级别

    @Column(name="cust_industry")
    private String custIndustry;//客户所属行业

    @Column(name="cust_phone")
    private String custPhone;//客户的联系方式

    @Column(name="cust_address")
    private String custAddress;//客户地址

    public Long getCustId() {
        return custId;
    }

    public void setCustId(Long custId) {
        this.custId = custId;
    }

    public String getCustName() {
        return custName;
    }

    public void setCustName(String custName) {
        this.custName = custName;
    }

    public String getCustSource() {
        return custSource;
    }

    public void setCustSource(String custSource) {
        this.custSource = custSource;
    }

    public String getCustLevel() {
        return custLevel;
    }

    public void setCustLevel(String custLevel) {
        this.custLevel = custLevel;
    }

    public String getCustIndustry() {
        return custIndustry;
    }

    public void setCustIndustry(String custIndustry) {
        this.custIndustry = custIndustry;
    }

    public String getCustPhone() {
        return custPhone;
    }

    public void setCustPhone(String custPhone) {
        this.custPhone = custPhone;
    }

    public String getCustAddress() {
        return custAddress;
    }

    public void setCustAddress(String custAddress) {
        this.custAddress = custAddress;
    }

    @Override
    public String toString() {
        return "Customer{" +
                "custId=" + custId +
                ", custName='" + custName + '\'' +
                ", custSource='" + custSource + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custPhone='" + custPhone + '\'' +
                ", custAddress='" + custAddress + '\'' +
                '}';
    }
}

创建dao

package com.baidu.dao;

import com.itcast.pojo.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;

import java.util.List;
//继承这两个接口之后该接口就拥有了基本的数据库操作方法
public interface CustomerMapper extends JpaSpecificationExecutor<Customer>,JpaRepository<Customer,Long> {

    //方法命名规范查询,findBy+字段名表示通过该字段查询

    public Customer findByCustName(String name);

	//Like表示通过CustName模糊查询，并且查询指定的地址
    public List<Customer> findByCustNameLikeAndCustAddress(String custName,String address);


    //自定义语句chaxun ?后面是参数的位置
    @Query("from Customer where custName = ?1 and id =?2")
    public Customer findNameAndId(String name,Long id);

    //自定义语句chaxun
    @Query("from Customer where custName = ?2 and id =?1")
    public Customer findIdAndName(Long id,String name);


    //自定义语句chaxun
    @Query("update Customer set custName=?2 where custId = ?1")
    @Modifying   //表示此方法不是查询
    public void updateIdByName(Long id,String name);

    //自定义sql查询
    @Query(value = "select * from cst_customer where cust_name = ?",nativeQuery = true)
    public List<Object[]> findName(String name);
}

创建测试类

import com.baidu.dao.CustomerMapper;
import com.baidu.pojo.Customer;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.test.annotation.Rollback;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import javax.persistence.criteria.*;
import java.util.List;
import java.util.Set;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class springDateTest {

    @Autowired
    private CustomerMapper customerMapper;


    @Test
    public void findAll(){
        List<Customer> list = customerMapper.findAll();
        for (Customer customer : list) {
            System.out.println(customer);
        }
    }


    @Test
    @Transactional
    public void findOne(){
    	//findone表示立即加载查询
        Customer customer = customerMapper.findOne(2l);
        System.out.println(customer);
        //getOne表示延迟加载
        Customer mapperOne = customerMapper.getOne(2l);
        System.out.println(mapperOne);
    }

    @Test
    public void insert(){
    	//当使用save方法时，如果有id就是更新，没有id就是保存
        Customer customer = new Customer();
        customer.setCustName("吉林");
        customerMapper.save(customer);
    }

    @Test
    public void update(){
        Customer customer = new Customer();
        customer.setCustId(2l);
        customer.setCustAddress("内蒙古");
        customerMapper.save(customer);
    }

    @Test
    public void findByName(){
        Customer customer = customerMapper.findByCustName("斗鱼");
        System.out.println(customer);
    }

    @Test
    public void findlike(){
        List<Customer> list = customerMapper.findByCustNameLikeAndCustAddress("吉%", "北京");
        for (Customer customer : list) {
            System.out.println(customer);
        }
    }

    @Test
    public void findNameAndId(){
        Customer customer = customerMapper.findNameAndId("龙珠", 4l);
        System.out.println(customer);
    }

    @Test
    public void findIdAndName(){
        Customer customer = customerMapper.findIdAndName(4l, "龙珠");
        System.out.println(customer);
    }

    @Test
    @Transactional
    @Rollback(value = false)
    public void updateName(){
        customerMapper.updateIdByName(4l, "霸天");
    }

    
	//条件查询
    @Test
    public void findOrder(){
        Specification<Customer> tSpecification = new Specification<Customer>() {
            public Predicate toPredicate(Root<Customer> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                Path<Object> custName = root.get("custName");
                Path<Object> custId = root.get("custId");
                Predicate predicate = cb.equal(custName.as(String.class), "霸天");
                Predicate predicate2 = cb.equal(custId.as(Long.class), 4l);
                Predicate p = cb.and(predicate, predicate2);
                return p;
            }
        };
        List<Customer> list = customerMapper.findAll(tSpecification);
        for (Customer customer : list) {
            System.out.println(customer);
        }
    }
	//分页查询
    @Test
    public void pageSplit(){
        Specification<Customer> tSpecification = new Specification<Customer>() {
            public Predicate toPredicate(Root<Customer> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                Path<Object> custId = root.get("custId");
                Predicate predicate = cb.greaterThanOrEqualTo(custId.as(Long.class), 2l);
                return predicate;
            }
        };
        Pageable pageable = new PageRequest(1,2);
        Page<Customer> page = customerMapper.findAll(tSpecification, pageable);
        long totalElements = page.getTotalElements();
        int totalPages = page.getTotalPages();
        System.out.println(totalElements);
        System.out.println(totalPages);
        List<Customer> list = page.getContent();
        for (Customer customer : list) {
            System.out.println(customer);
        }
    }
}