构建微服务：如何优雅的使用mybaits

*:first-child{margin-top: 0 !important}.markdown-body>*:last-child{margin-bottom: 0 !important}.markdown-body .absent{color: #c00}.markdown-body .anchor{position: absolute;top: 0;left: 0;display: block;padding-right: 6px;padding-left: 30px;margin-left: -30px}.markdown-body .anchor:focus{outline: none}.markdown-body h1,.markdown-body h2,.markdown-body h3,.markdown-body h4,.markdown-body h5,.markdown-body h6{position: relative;margin-top: 1em;margin-bottom: 16px;font-weight: bold;line-height: 1.4}.markdown-body h1 .octicon-link,.markdown-body h2 .octicon-link,.markdown-body h3 .octicon-link,.markdown-body h4 .octicon-link,.markdown-body h5 .octicon-link,.markdown-body h6 .octicon-link{display: none;color: #000;vertical-align: middle}.markdown-body h1:hover .anchor,.markdown-body h2:hover .anchor,.markdown-body h3:hover .anchor,.markdown-body h4:hover .anchor,.markdown-body h5:hover .anchor,.markdown-body h6:hover .anchor{padding-left: 8px;margin-left: -30px;text-decoration: none}.markdown-body h1:hover .anchor .octicon-link,.markdown-body h2:hover .anchor .octicon-link,.markdown-body h3:hover .anchor .octicon-link,.markdown-body h4:hover .anchor .octicon-link,.markdown-body h5:hover .anchor .octicon-link,.markdown-body h6:hover .anchor .octicon-link{display: inline-block}.markdown-body h1 tt,.markdown-body h1 code,.markdown-body h2 tt,.markdown-body h2 code,.markdown-body h3 tt,.markdown-body h3 code,.markdown-body h4 tt,.markdown-body h4 code,.markdown-body h5 tt,.markdown-body h5 code,.markdown-body h6 tt,.markdown-body h6 code{font-size: inherit}.markdown-body h1{padding-bottom: 0.3em;font-size: 2.25em;line-height: 1.2;border-bottom: 1px solid #eee}.markdown-body h1 .anchor{line-height: 1}.markdown-body h2{padding-bottom: 0.3em;font-size: 1.75em;line-height: 1.225;border-bottom: 1px solid #eee}.markdown-body h2 .anchor{line-height: 1}.markdown-body h3{font-size: 1.5em;line-height: 1.43}.markdown-body h3 .anchor{line-height: 1.2}.markdown-body h4{font-size: 1.25em}.markdown-body h4 .anchor{line-height: 1.2}.markdown-body h5{font-size: 1em}.markdown-body h5 .anchor{line-height: 1.1}.markdown-body h6{font-size: 1em;color: #777}.markdown-body h6 .anchor{line-height: 1.1}.markdown-body p,.markdown-body blockquote,.markdown-body ul,.markdown-body ol,.markdown-body dl,.markdown-body table,.markdown-body pre{margin-top: 0;margin-bottom: 16px}.markdown-body hr{height: 4px;padding: 0;margin: 16px 0;background-color: #e7e7e7;border: 0 none}.markdown-body ul,.markdown-body ol{padding-left: 2em}.markdown-body ul.no-list,.markdown-body ol.no-list{padding: 0;list-style-type: none}.markdown-body ul ul,.markdown-body ul ol,.markdown-body ol ol,.markdown-body ol ul{margin-top: 0;margin-bottom: 0}.markdown-body li>p{margin-top: 16px}.markdown-body dl{padding: 0}.markdown-body dl dt{padding: 0;margin-top: 16px;font-size: 1em;font-style: italic;font-weight: bold}.markdown-body dl dd{padding: 0 16px;margin-bottom: 16px}.markdown-body blockquote{padding: 0 15px;color: #777;border-left: 4px solid #ddd}.markdown-body blockquote>:first-child{margin-top: 0}.markdown-body blockquote>:last-child{margin-bottom: 0}.markdown-body table{display: block;width: 100%;overflow: auto;word-break: normal;word-break: keep-all}.markdown-body table th{font-weight: bold}.markdown-body table th,.markdown-body table td{padding: 6px 13px;border: 1px solid #ddd}.markdown-body table tr{background-color: #fff;border-top: 1px solid #ccc}.markdown-body table tr:nth-child(2n){background-color: #f8f8f8}.markdown-body img{max-width: 100%;box-sizing: border-box}.markdown-body span.frame{display: block;overflow: hidden}.markdown-body span.frame>span{display: block;float: left;width: auto;padding: 7px;margin: 13px 0 0;overflow: hidden;border: 1px solid #ddd}.markdown-body span.frame span img{display: block;float: left}.markdown-body span.frame span span{display: block;padding: 5px 0 0;clear: both;color: #333}.markdown-body span.align-center{display: block;overflow: hidden;clear: both}.markdown-body span.align-center>span{display: block;margin: 13px auto 0;overflow: hidden;text-align: center}.markdown-body span.align-center span img{margin: 0 auto;text-align: center}.markdown-body span.align-right{display: block;overflow: hidden;clear: both}.markdown-body span.align-right>span{display: block;margin: 13px 0 0;overflow: hidden;text-align: right}.markdown-body span.align-right span img{margin: 0;text-align: right}.markdown-body span.float-left{display: block;float: left;margin-right: 13px;overflow: hidden}.markdown-body span.float-left span{margin: 13px 0 0}.markdown-body span.float-right{display: block;float: right;margin-left: 13px;overflow: hidden}.markdown-body span.float-right>span{display: block;margin: 13px auto 0;overflow: hidden;text-align: right}.markdown-body code,.markdown-body tt{padding: 0;padding-top: 0.2em;padding-bottom: 0.2em;margin: 0;font-size: 85%;background-color: rgba(0,0,0,0.04);border-radius: 3px}.markdown-body code:before,.markdown-body code:after,.markdown-body tt:before,.markdown-body tt:after{letter-spacing: -0.2em;content: "\00a0"}.markdown-body code br,.markdown-body tt br{display: none}.markdown-body del code{text-decoration: inherit}.markdown-body pre>code{padding: 0;margin: 0;font-size: 100%;word-break: normal;white-space: pre;background: transparent;border: 0}.markdown-body .highlight{margin-bottom: 16px}.markdown-body .highlight pre,.markdown-body pre{padding: 16px;overflow: auto;font-size: 85%;line-height: 1.45;background-color: #f7f7f7;border-radius: 3px}.markdown-body .highlight pre{margin-bottom: 0;word-break: normal}.markdown-body pre{word-wrap: normal}.markdown-body pre code,.markdown-body pre tt{display: inline;max-width: initial;padding: 0;margin: 0;overflow: initial;line-height: inherit;word-wrap: normal;background-color: transparent;border: 0}.markdown-body pre code:before,.markdown-body pre code:after,.markdown-body pre tt:before,.markdown-body pre tt:after{content: normal}.markdown-body kbd{display: inline-block;padding: 3px 5px;font-size: 11px;line-height: 10px;color: #555;vertical-align: middle;background-color: #fcfcfc;border: solid 1px #ccc;border-bottom-color: #bbb;border-radius: 3px;box-shadow: inset 0 -1px 0 #bbb}.codehilite{background: #ffffff}.codehilite .c{color: #999988;font-style: italic}.codehilite .err{color: #a61717;background-color: #e3d2d2}.codehilite .k{color: #000000;font-weight: bold}.codehilite .o{color: #000000;font-weight: bold}.codehilite .cm{color: #999988;font-style: italic}.codehilite .cp{color: #999999;font-weight: bold}.codehilite .c1{color: #999988;font-style: italic}.codehilite .cs{color: #999999;font-weight: bold;font-style: italic}.codehilite .gd{color: #000000;background-color: #ffdddd}.codehilite .gd .x{color: #000000;background-color: #ffaaaa}.codehilite .ge{color: #000000;font-style: italic}.codehilite .gr{color: #aa0000}.codehilite .gh{color: #999999}.codehilite .gi{color: #000000;background-color: #ddffdd}.codehilite .gi .x{color: #000000;background-color: #aaffaa}.codehilite .go{color: #888888}.codehilite .gp{color: #555555}.codehilite .gs{font-weight: bold}.codehilite .gu{color: #aaaaaa}.codehilite .gt{color: #aa0000}.codehilite .kc{color: #000000;font-weight: bold}.codehilite .kd{color: #000000;font-weight: bold}.codehilite .kp{color: #000000;font-weight: bold}.codehilite .kr{color: #000000;font-weight: bold}.codehilite .kt{color: #445588;font-weight: bold}.codehilite .m{color: #009999}.codehilite .s{color: #d14}.codehilite .na{color: #008080}.codehilite .nb{color: #0086b3}.codehilite .nc{color: #445588;font-weight: bold}.codehilite .no{color: #008080}.codehilite .ni{color: #800080}.codehilite .ne{color: #990000;font-weight: bold}.codehilite .nf{color: #990000;font-weight: bold}.codehilite .nn{color: #555555}.codehilite .nt{color: #000080}.codehilite .nv{color: #008080}.codehilite .ow{color: #000000;font-weight: bold}.codehilite .w{color: #bbbbbb}.codehilite .mf{color: #009999}.codehilite .mh{color: #009999}.codehilite .mi{color: #009999}.codehilite .mo{color: #009999}.codehilite .sb{color: #d14}.codehilite .sc{color: #d14}.codehilite .sd{color: #d14}.codehilite .s2{color: #d14}.codehilite .se{color: #d14}.codehilite .sh{color: #d14}.codehilite .si{color: #d14}.codehilite .sx{color: #d14}.codehilite .sr{color: #009926}.codehilite .s1{color: #d14}.codehilite .ss{color: #990073}.codehilite .bp{color: #999999}.codehilite .vc{color: #008080}.codehilite .vg{color: #008080}.codehilite .vi{color: #008080}.codehilite .il{color: #009999}

-->

这两天启动了一个新项目因为项目组成员一直都使用的是mybaits，虽然个人比较喜欢jpa这种极简的模式，但是为了项目保持统一性技术选型还是定了 mybaits。到网上找了一下关于spring boot和mybaits组合的相关资料，各种各样的形式都有，看的人心累，结合了mybaits的官方demo和文档终于找到了最简的两种模式，花了一天时间总结后分享出来。

orm框架的本质是简化编程中操作数据库的编码，发展到现在基本上就剩两家了，一个是宣称可以不用写一句sql的hibernate，一个是可以灵活调试动态sql的mybiats,两者各有特点，在企业级系统开发中可以根据需求灵活使用。发现一个有趣的现象：传统企业大都喜欢使用hibernate,互联网行业通常使用mybiats。

hibernate特点就是所有的sql都用Java代码来生成，不用跳出程序去写（看）sql，有着编程的完整性，发展到最顶端就是spring data jpa这种模式了，基本上根据方法名就可以生成对应的sql了，有不太了解的可以看我的上篇文章构建微服务：spring data jpa的使用。

mybaits初期使用比较麻烦，需要各种配置文件、实体类、dao层映射关联、还有一大推其它配置。当然mybaits也发现了这种弊端，初期开发了generator可以根据表结果自动生产实体类、配置文件和dao层代码，可以减轻一部分开发量；后期也进行了大量的优化可以使用注解了，自动管理dao层和配置文件等，发展到最顶端就是今天要讲的这种模式了，mybatis-spring-boot-starter就是springboot+mybaits可以完全注解不用配置文件，也可以简单配置轻松上手。

现在想想spring boot 就是牛鼻呀，任何东西只要关联到spring boot都是化繁为简。

mybatis-spring-boot-starter

官方说明：MyBatis Spring-Boot-Starter will help you use MyBatis with Spring Boot
其实就是myBatis看spring boot这么火热也开发出一套解决方案来凑凑热闹,但这一凑确实解决了很多问题，使用起来确实顺畅了许多。mybatis-spring-boot-starter主要有两种解决方案，一种是使用注解解决一切问题，一种是简化后的老传统。

当然任何模式都需要首先引入mybatis-spring-boot-starter的pom文件,现在最新版本是1.1.1（刚好快到双11了 :)）

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.1.1</version>
</dependency>

好了下来分别介绍两种开发模式

无配置文件注解版

就是一切使用注解搞定。

1 添加相关maven文件

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.1.1</version>
    </dependency>
     <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
    </dependency>
</dependencies>

完整的pom包这里就不贴了，大家直接看源码

2、`application.properties` 添加相关配置

mybatis.type-aliases-package=com.neo.entity

spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = root

springboot会自动加载spring.datasource.*相关配置，数据源就会自动注入到sqlSessionFactory中，sqlSessionFactory会自动注入到Mapper中，对了你一切都不用管了，直接拿起来使用就行了。

在启动类中添加对mapper包扫描@MapperScan

@SpringBootApplication
@MapperScan("com.neo.mapper")
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

或者直接在Mapper类上面添加注解@Mapper,建议使用上面那种，不然每个mapper加个注解也挺麻烦的

3、开发Mapper

第三步是最关键的一块，sql生产都在这里

public interface UserMapper {

    @Select("SELECT * FROM users")
    @Results({
        @Result(property = "userSex",  column = "user_sex", javaType = UserSexEnum.class),
        @Result(property = "nickName", column = "nick_name")
    })
    List<UserEntity> getAll();

    @Select("SELECT * FROM users WHERE id = #{id}")
    @Results({
        @Result(property = "userSex",  column = "user_sex", javaType = UserSexEnum.class),
        @Result(property = "nickName", column = "nick_name")
    })
    UserEntity getOne(Long id);

    @Insert("INSERT INTO users(userName,passWord,user_sex) VALUES(#{userName}, #{passWord}, #{userSex})")
    void insert(UserEntity user);

    @Update("UPDATE users SET userName=#{userName},nick_name=#{nickName} WHERE id =#{id}")
    void update(UserEntity user);

    @Delete("DELETE FROM users WHERE id =#{id}")
    void delete(Long id);

}

为了更接近生产我特地将user_sex、nick_name两个属性在数据库加了下划线和实体类属性名不一致，另外user_sex使用了枚举

@Select 是查询类的注解，所有的查询均使用这个

@Result 修饰返回的结果集，关联实体类属性和数据库字段一一对应，如果实体类属性和数据库属性名保持一致，就不需要这个属性来修饰。

@Insert 插入数据库使用，直接传入实体类会自动解析属性到对应的值

@Update 负责修改，也可以直接传入对象

@delete 负责删除

了解更多属性参考这里

注意，使用#符号和$符号的不同：

// This example creates a prepared statement, something like select * from teacher where name = ?;
@Select("Select * from teacher where name = #{name}")
Teacher selectTeachForGivenName(@Param("name") String name);

// This example creates n inlined statement, something like select * from teacher where name = ‘someName‘;
@Select("Select * from teacher where name = ‘${name}‘)
Teacher selectTeachForGivenName(@Param("name") String name);

4、使用

上面三步就基本完成了相关dao层开发，使用的时候当作普通的类注入进入就可以了

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {

    @Autowired
    private UserMapper UserMapper;

    @Test
    public void testInsert() throws Exception {
        UserMapper.insert(new UserEntity("aa", "a123456", UserSexEnum.MAN));
        UserMapper.insert(new UserEntity("bb", "b123456", UserSexEnum.WOMAN));
        UserMapper.insert(new UserEntity("cc", "b123456", UserSexEnum.WOMAN));

        Assert.assertEquals(3, UserMapper.getAll().size());
    }

    @Test
    public void testQuery() throws Exception {
        List<UserEntity> users = UserMapper.getAll();
        System.out.println(users.toString());
    }

    @Test
    public void testUpdate() throws Exception {
        UserEntity user = UserMapper.getOne(3l);
        System.out.println(user.toString());
        user.setNickName("neo");
        UserMapper.update(user);
        Assert.assertTrue(("neo".equals(UserMapper.getOne(3l).getNickName())));
    }
}

源码中controler层有完整的增删改查，这里就不贴了
源码在这里spring-boot-mybaits-annotation

极简xml版本

极简xml版本保持映射文件的老传统，优化主要体现在不需要实现dao的是实现层，系统会自动根据方法名在映射文件中找对应的sql.

1、配置

pom文件和上个版本一样，只是application.properties新增以下配置

mybatis.config-locations=classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

指定了mybatis基础配置文件和实体类映射文件的地址

mybatis-config.xml 配置

<configuration>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

这里也可以添加一些mybaits基础的配置

2、添加User的映射文件

<mapper namespace="com.neo.mapper.UserMapper" >
    <resultMap id="BaseResultMap" type="com.neo.entity.UserEntity" >
        <id column="id" property="id" jdbcType="BIGINT" />
        <result column="userName" property="userName" jdbcType="VARCHAR" />
        <result column="passWord" property="passWord" jdbcType="VARCHAR" />
        <result column="user_sex" property="userSex" javaType="com.neo.enums.UserSexEnum"/>
        <result column="nick_name" property="nickName" jdbcType="VARCHAR" />
    </resultMap>

    <sql id="Base_Column_List" >
        id, userName, passWord, user_sex, nick_name
    </sql>

    <select id="getAll" resultMap="BaseResultMap"  >
       SELECT
       <include refid="Base_Column_List" />
       FROM users
    </select>

    <select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
        SELECT
       <include refid="Base_Column_List" />
       FROM users
       WHERE id = #{id}
    </select>

    <insert id="insert" parameterType="com.neo.entity.UserEntity" >
       INSERT INTO
            users
            (userName,passWord,user_sex)
        VALUES
            (#{userName}, #{passWord}, #{userSex})
    </insert>

    <update id="update" parameterType="com.neo.entity.UserEntity" >
       UPDATE
            users
       SET
        <if test="userName != null">userName = #{userName},</if>
        <if test="passWord != null">passWord = #{passWord},</if>
        nick_name = #{nickName}
       WHERE
            id = #{id}
    </update>

    <delete id="delete" parameterType="java.lang.Long" >
       DELETE FROM
             users
       WHERE
             id =#{id}
    </delete>
</mapper>

其实就是把上个版本中mapper的sql搬到了这里的xml中了

3、编写Dao层的代码

public interface UserMapper {

    List<UserEntity> getAll();

    UserEntity getOne(Long id);

    void insert(UserEntity user);

    void update(UserEntity user);

    void delete(Long id);

}

对比上一步这里全部只剩了接口方法

4、使用

使用和上个版本没有任何区别，大家就看代码吧

老传统优化版本代码在这里

如何选择

两种模式各有特点，注解版适合简单快速的模式，其实像现在流行的这种微服务模式，一个微服务就会对应一个自已的数据库，多表连接查询的需求会大大的降低，会越来越适合这种模式。

老传统模式比适合大型项目，可以灵活的动态生成SQL，方便调整SQL，也有痛痛快快，洋洋洒洒的写SQL的感觉。

完整代码地址

前几篇关于微服务的文章地址：

时间： 2024-10-12 17:22:05

构建微服务：如何优雅的使用mybaits

mybatis-spring-boot-starter

无配置文件注解版

1 添加相关maven文件

2、`application.properties` 添加相关配置

3、开发Mapper

4、使用

极简xml版本

1、配置

2、添加User的映射文件

3、编写Dao层的代码

4、使用

如何选择