用Spring Data JPA 基于内存存储pojo的简单案例
poject结构如下：

Customer.java类是一个pojo类，代码如下：

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">    <modelVersion>4.0.0</modelVersion>    <groupId>org.springframework</groupId>    <artifactId>gs-accessing-data-jpa</artifactId>    <version>0.1.0</version>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>0.5.0.M4</version>    </parent>    <dependencies>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-orm</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.data</groupId>            <artifactId>spring-data-jpa</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.hibernate</groupId>            <artifactId>hibernate-entitymanager</artifactId>        </dependency>        <dependency>            <groupId>com.h2database</groupId>            <artifactId>h2</artifactId>        </dependency>    </dependencies>    <properties>        <!-- use UTF-8 for everything -->        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>        <start-class>hello.Application</start-class>    </properties>    <build>        <plugins>            <plugin>                 <artifactId>maven-compiler-plugin</artifactId>                 <version>2.3.2</version>             </plugin>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build>    <repositories>        <repository>            <id>spring-snapshots</id>            <name>Spring Snapshots</name>            <url>http://repo.spring.io/libs-snapshot</url>            <snapshots>                <enabled>true</enabled>            </snapshots>        </repository>        <repository>            <id>spring-milestones</id>            <name>Spring Milestones</name>            <url>http://repo.spring.io/libs-milestone</url>            <snapshots>                <enabled>false</enabled>            </snapshots>        </repository>        <repository>            <id>org.jboss.repository.releases</id>            <name>JBoss Maven Release Repository</name>            <url>https://repository.jboss.org/nexus/content/repositories/releases</url>            <snapshots>                <enabled>false</enabled>            </snapshots>        </repository>    </repositories>    <pluginRepositories>        <pluginRepository>            <id>spring-snapshots</id>            <name>Spring Snapshots</name>            <url>http://repo.spring.io/libs-snapshot</url>            <snapshots>                <enabled>true</enabled>            </snapshots>        </pluginRepository>        <pluginRepository>            <id>spring-milestones</id>            <name>Spring Milestones</name>            <url>http://repo.spring.io/libs-milestone</url>            <snapshots>                <enabled>false</enabled>            </snapshots>        </pluginRepository>    </pluginRepositories></project>

这是从spring官网学习的，有不对的地方欢迎指导