springdata jpa入门crud

新建一个普通的maven工程

新建数据库表

CREATE TABLE cst_customer (
cust_id BIGINT(32) NOT NULL AUTO_INCREMENT COMMENT '客户编号(主键)',
cust_name VARCHAR(32) NOT NULL COMMENT '客户名称(公司名称)',
cust_source VARCHAR(32) DEFAULT NULL COMMENT '客户信息来源',
cust_industry VARCHAR(32) DEFAULT NULL COMMENT '客户所属行业',
cust_level VARCHAR (32) DEFAULT NULL COMMENT '客户级别',
cust_address VARCHAR (128) DEFAULT NULL COMMENT '客户联系地址',
cust_phone VARCHAR(64) DEFAULT NULL COMMENT '客户联系电话',
PRIMARY KEY (`cust_id`)
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

导入所需要的依赖

<properties>
        <spring.version>4.2.4.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>4.9</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>

        <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>

        <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>4.2.4.RELEASE</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 -->
    </dependencies>

在resources中新建一个applicationContext.xml的配置文件

<?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">

    <!--spring 和 spring data jpa的配置-->

    <!-- 1.创建entityManagerFactory对象交给spring容器管理-->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">

        <property name="dataSource" ref="dataSource"/>

        <!--配置的扫描的包（实体类所在的包） -->
        <property name="packagesToScan" value="com.feng.pojo"/>

        <!-- jpa的实现厂家 -->
        <property name="persistenceProvider">
            <bean class="org.hibernate.jpa.HibernatePersistenceProvider"></bean>
        </property>

        <!--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>

    </bean>

    <!--2.创建数据库连接池 -->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/jpa?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf8" />
        <property name="user" value="root" />
        <property name="password" value="123456" />
    </bean>


    <!-- 3.整合spring data jpa-->
    <jpa:repositories base-package="com.feng.dao" transaction-manager-ref="transactionManager"
                      entity-manager-factory-ref="entityManagerFactory">

    </jpa:repositories>

    <!-- 4.事务管理器-->
    <!-- JPA事务管理器  -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>


    <!-- 5. 配置包扫描-->
    <context:component-scan base-package="com.feng"/>
</beans>

写下实体类和dao层

package com.feng.pojo;

import javax.persistence.*;

/**
 * 1.实体类和表的映射关系
 *      @Eitity
 *      @Table
 * 2.类中属性和表中字段的映射关系
 *      @Id
 *      @GeneratedValue
 *      @Column
 */
@Entity
@Table(name = "cst_customer")
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "cust_id")
    private Long custId;
    @Column(name = "cust_address")
    private String custAddress;
    @Column(name = "cust_industry")
    private String custIndustry;
    @Column(name = "cust_level")
    private String custLevel;
    @Column(name = "cust_name")
    private String custName;
    @Column(name = "cust_phone")
    private String custPhone;
    @Column(name = "cust_source")
    private String custSource;

    public Long getCustId() {
        return custId;
    }

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

    public String getCustAddress() {
        return custAddress;
    }

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

    public String getCustIndustry() {
        return custIndustry;
    }

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

    public String getCustLevel() {
        return custLevel;
    }

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

    public String getCustName() {
        return custName;
    }

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

    public String getCustPhone() {
        return custPhone;
    }

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

    public String getCustSource() {
        return custSource;
    }

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

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

package com.feng.dao;

import com.feng.pojo.Customer;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

/**
 * 符合SpringDataJpa的dao层接口规范
 *      JpaRepository<操作的实体类类型，实体类中主键属性的类型>
 *          * 封装了基本CRUD操作
 *      JpaSpecificationExecutor<操作的实体类类型>
 *          * 封装了复杂查询（分页）
 */
public interface CustomerDao extends JpaRepository<Customer,Long>, JpaSpecificationExecutor<Customer> {
}

编写测试类

package com.feng;

import com.feng.dao.CustomerDao;
import com.feng.pojo.Customer;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)//声明spring提供的单元测试环境
@ContextConfiguration(locations = "classpath:applicationContext.xml")//指定spring容器的配置信息
public class MyTest {

    @Autowired
    private CustomerDao customerDao;


    /**
     * 根据id查询
     */
    @Test
    public void test01(){

        Customer customer = customerDao.findOne(1l);

        System.out.println(customer);
    }


    /**
     * save : 保存或者更新
     *      根据传递的对象是否存在主键id，
     *      如果没有id主键属性：保存
     *      存在id主键属性，根据id查询数据，更新数据
     */
    @Test
    public void tesSave(){

        Customer customer = new Customer();

        customer.setCustName("小码哥");

        customer.setCustIndustry("码哥教育");

        customerDao.save(customer);
    }


    @Test
    public void tesUpdate(){

        Customer customer = new Customer();

        customer.setCustId(5l);
        customer.setCustName("小码哥");

        customer.setCustIndustry("千峰教育");

        customerDao.save(customer);
    }

    @Test
    public void testDelete () {
        customerDao.delete(3l);
    }


    /**
     * 查询所有
     */
    @Test
    public void testFindAll(){

        List<Customer> all = customerDao.findAll();
        for (Customer customer : all) {

            System.out.println(customer);
        }
    }


    /**
     * 测试统计查询：查询客户的总数量
     *      count:统计总条数
     */
    @Test
    public void testCount(){

        long count = customerDao.count();

        System.out.println(count);
    }


    /**
     * 测试：判断id为4的客户是否存在
     *      1. 可以查询以下id为4的客户
     *          如果值为空，代表不存在，如果不为空，代表存在
     *      2. 判断数据库中id为4的客户的数量
     *          如果数量为0，代表不存在，如果大于0，代表存在
     */
    @Test
    public void testExists(){

        boolean exists = customerDao.exists(5l);

        System.out.println(exists);
    }

    /**
     * 根据id从数据库查询
     *      @Transactional : 保证getOne正常运行
     *
     *  findOne：
     *      em.find()           :立即加载
     *  getOne：
     *      em.getReference     :延迟加载
     *      * 返回的是一个客户的动态代理对象
     *      * 什么时候用，什么时候查询
     */
    @Test
   @Transactional
    public void testGetOne(){

        Customer customer = customerDao.getOne(5l);
        System.out.println(customer);
    }
}