JPA(Java Persistence API)是一个基于O/R映射(Object-Relational Mapping)的标准规范，主要实现包括Hibernate、EclipseLink和OpenJPA等。
orm框架的本质是简化编程中操作数据库的编码[2]，JPA 方便程序员不写sql语句，而 MyBatis 呢，则适合灵活调试动态sql。
本文梳理了springboot整合jpa和mybatis的大体过程，并给出了两个demo。
1 在docker环境下运行数据库
首先安装vmware虚拟机，然后安装docker。
在docker中 pull Oracle镜像并启动容器。
最后把虚拟机的1521端口映射到宿主机上。
- 数据库：Oracle XE 11g
- 宿主机数据库客户端：SQL developer
注意必须先禁用/etc/selinux/config中selinux选项，然后重启系统。否则安装好的oracle没有默认实例
[root@localhost fsj]# docker pull wnameless/oracle-xe-11g
查看已经安装的镜像
[root@localhost fsj]# docker images
启动容器
[root@localhost fsj]# docker run -d -p 9091:8080 -p 1521:1521 --name xe wnameless/oracle-xe-11g
9bf0a03006471a2268b239c32bed00737ee94ef93f92650226c056b0fb891b40
[root@localhost fsj]# netstat -nlp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 948/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1051/master
tcp6 0 0 :::1521 :::* LISTEN 5403/docker-proxy-c
tcp6 0 0 :::22 :::* LISTEN 948/sshd
tcp6 0 0 ::1:25 :::* LISTEN 1051/master
tcp6 0 0 :::9091 :::* LISTEN 5396/docker-proxy-c
udp 0 0 0.0.0.0:68 0.0.0.0:* 767/dhclient
udp 0 0 0.0.0.0:47439 0.0.0.0:* 767/dhclient
udp6 0 0 :::17787 :::* 767/dhclient
raw6 0 0 :::58 :::* 7 646/NetworkManager
[root@localhost fsj]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2865df7bf94a wnameless/oracle-xe-11g "/bin/sh -c \'/usr/sbi" 5 seconds ago Up 2 seconds 22/tcp, 0.0.0.0:1521->1521/tcp, 0.0.0.0:9091->8080/tcp xe
进入容器的shell: docker exec -it container-id/container-name bash
[root@localhost fsj]# docker exec -it xe bash
然后以system/oracle登陆。
$ sqlplus system/oracle
表空间
创建
SQL> create tablespace ts_fsj
datafile \'/u01/app/oracle/oradata/XE/ts_fsj.dbf\'
size 50m
autoextend on
maxsize 10g;
查看表空间
SQL> select name from v$datafile
SQL> select file_name,tablespace_name from dba_data_files;
新建用户
create user boot
identified by boot
default tablespace ts_fsj
temporary tablespace temp
profile default
grant connect,resource,dba to boot
2 springboot整合jpa
新建maven项目：
mvn archetype:generate \\
-DgroupId=com.fsj \\
-DartifactId=ex01 \\
-DarchetypeArtifactId=maven-archetype-quickstart \\
-DinteractiveMode=false
要建立数据访问DAO层，需要定义一个继承了JpaRepository的接口。然后编写查询方法，例如
public interface PersonRepository extends JpaRepository<Person, Long> {
// 通过Address相等查询，参数为address
List<Person> findByAddress(String address);
Person findByNameAndAddress(String name, String address);
@Query("select p from Person p where p.name= :name and p.address= :address")
Person withNameAndAddressQuery(@Param("name") String name, @Param("address") String address);
// 对应Person实体中的 @NameQuery
Person withNameAndAddressNamedQuery(String name, String address);
}
简单的查询方法包括：
1、通过属性名查询
使用了findBy、Like、And等关键字命名方法，那么就不需要编写具体的sql了，比如
通过Address相等查询，参数为address，可以写成List<Person> findByAddress(String address);
相当于JPQL： select p from Person p where p.address=?1
完整的查询关键字见：Spring Data JPA 查询方法支持的关键字
2、使用@Query注解
3、使用@NameQuery注解
支持用JPA的NameQuery来定义查询方法，一个名称映射一个查询语句
dao层写好之后就可以在controller层直接调用了。
3 springboot整合mybatis
1、新建maven项目
2、修改pom文件，添加依赖包
3、修改application.properties 添加相关配置
4、在数据库中添加测试用city表和数据
CREATE TABLE city (
id VARCHAR2(32) NOT NULL ,
name VARCHAR2(64),
state VARCHAR2(64),
country VARCHAR2(64),
PRIMARY KEY(ID)
);
INSERT INTO city (id, name, state, country) VALUES (\'1\', \'San Francisco\', \'CA\', \'US\');
INSERT INTO city (id, name, state, country) VALUES (\'2\', \'Beijing\', \'BJ\', \'CN\');
INSERT INTO city (id, name, state, country) VALUES (\'3\', \'Guangzhou\', \'GD\', \'CN\');
COMMIT ;
5、开发Mapper。使用注解和xml两种方式
public interface CityMapper {
@Select("SELECT id, name, state, country FROM city WHERE state = #{state}")
City queryByState(String state);
@Select("select * from city")
List<City> queryAll();
//xml方式，适合复杂查询
List<City> fuzzyQuery(@Param("name") String name);
}
对应的CityMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.fsj.dao.CityMapper">
<sql id="Base_Column_List">
id, name, state, country
</sql>
<resultMap id="BaseResultMap" type="com.fsj.entity.City">
<result column="id" property="id"/>
<result column="name" property="name"/>
<result column="state" property="state"/>
<result column="country" property="country"/>
</resultMap>
<select id="fuzzyQuery" resultMap="BaseResultMap">
SELECT * FROM CITY
WHERE 1>0
<if test="name != null and name != \'\' ">
<bind name="fuzzyname" value=" \'%\'+name+\'%\' "/>
AND UPPER(name) like #{fuzzyname, jdbcType=VARCHAR}
</if>
</select>
</mapper>
6、添加测试
@RunWith(SpringRunner.class)
@SpringBootTest
//@Transactional
public class CityTest {
private MockMvc mvc1;
private MockMvc mvc2;
private String url_get_all;
@Autowired
CityMapper cityMapper;
@Autowired
WebApplicationContext webApplicationContext;
@Before
public void setUp() throws Exception {
mvc1 = MockMvcBuilders.standaloneSetup(new CityController()).build();
mvc2 = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
url_get_all = "/mybatis/queryAll";
}
@Test
public void testQueryAll() throws Exception {
List<City> expected = cityMapper.queryAll();
List<City> actual = cityMapper.queryAll();
Assert.assertEquals("queryAll测试失败", JSON.toJSONString(expected), JSON.toJSONString(actual));
}
/**
* 验证controller是否正常响应并打印返回结果
* http://www.ityouknow.com/springboot/2017/05/09/springboot-deploy.html
* 此处MockMvc对象请求失败，可能只适用于springboot1.3.6旧版本
* @throws Exception
*/
@Test
public void testRequest() throws Exception {
mvc1.perform(MockMvcRequestBuilders.get(url_get_all).accept(MediaType.APPLICATION_JSON))
.andExpect(MockMvcResultMatchers.status().isOk())
.andDo(MockMvcResultHandlers.print())
.andReturn();
/*output
* org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
*/
}
@Test
public void testRequest2() throws Exception {
MvcResult res = mvc2.perform(MockMvcRequestBuilders.get(url_get_all).accept(MediaType.APPLICATION_JSON))
.andReturn();
int status = res.getResponse().getStatus();
String content = res.getResponse().getContentAsString();
List<City> expected = cityMapper.queryAll();
Assert.assertEquals(200, status);
Assert.assertEquals(JSON.toJSONString(expected), content);//json元素顺序不同，测试不过
/*json对象比较，在python中自动排序，对象比较为True
Expected :[{"country":"US","id":"1","name":"San Francisco","state":"CA"},{"country":"CN","id":"2","name":"Beijing","state":"BJ"},{"country":"CN","id":"3","name":"Guangzhou","state":"GD"}]
Actual :[{"id":"1","name":"San Francisco","state":"CA","country":"US"},{"id":"2","name":"Beijing","state":"BJ","country":"CN"},{"id":"3","name":"Guangzhou","state":"GD","country":"CN"}]
* */
}
}