一个spring data jpa的有关问题

一个spring data jpa的问题
实体类：
Product.java

package com.original.springdata.entity;


import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;


@Entity

@Table(name = "product")

public class Product {

	private Integer id;

	private String name;

	private Float price;


	@Id

	@GeneratedValue(strategy=GenerationType.AUTO)

	public Integer getId() {

		return id;

	}

	public void setId(Integer id) {

		this.id = id;

	}

	public String getName() {

		return name;

	}

	public void setName(String name) {

		this.name = name;

	}

	public Float getPrice() {

		return price;

	}

	public void setPrice(Float price) {

		this.price = price;

	}


}

Dao类：
ProductDao.java

package com.original.springdata.dao;


import org.springframework.data.repository.Repository;


import com.original.springdata.entity.Product;


public interface ProductDao extends Repository<Product,Integer>{

	public Product save(Product product);

}

Service接口：
ProductService.java

package com.original.springdata.service;


import com.original.springdata.entity.Product;


public interface ProductService {

	public Product createNewProduct(String name,float price);

}

ServiceImpl类：
ProductServiceImpl.java

package com.original.springdata.service;


import javax.transaction.Transactional;


import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;


import com.original.springdata.dao.ProductDao;

import com.original.springdata.entity.Product;


@Service("productService")

public class ProductServiceImpl implements ProductService {


	@Autowired

	private ProductDao productDao;


	@Override

	@Transactional

	public Product createNewProduct(String name, float price) {

		Product product = new Product();

		product.setName(name);

		product.setPrice(price);

		return productDao.save(product);

	}


}

测试类：
Test.java

package com.original.springdata.test;


import org.springframework.context.support.ClassPathXmlApplicationContext;


import com.original.springdata.service.ProductService;


public class Test {

	public static void main(String[] args) {

		ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");

		ProductService productService = ctx.getBean("productService", ProductService.class);

		productService.createNewProduct("calculator", 100);

		ctx.close();

	}

}

jpa配置文件：
persistence.xml

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">

	<persistence-unit name="springdata">

		<class>com.original.springdata.entity.Product</class>

		<properties>

			<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>

			<property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/springdata"/>

			<property name="hibernate.connection.username" value="root"/>

			<property name="hibernate.connection.password" value="root"/>

			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>

			<property name="hibernate.show_sql" value="true"/>

			<property name="hibernate.format_sql" value="true"/>

			<property name="hibernate.use_sql_comments" value="false"/>

			<property name="hibernate.hbm2ddl.auto" value="update"/>

		</properties>

	</persistence-unit>

</persistence>

spring配置文件：
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:jpa="http://www.springframework.org/schema/data/jpa"

	xmlns:tx="http://www.springframework.org/schema/tx"

	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-3.2.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-3.2.xsd">