最近一直都在学习java，发现目前java招聘中，mybatis出现的频率挺高的，可能是目前java开发中使用比较多的数据库orm框架。于是我准备研究下spring boot和mybatis的整合。

1.在pom.xml文件中添加下面的配置

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 <dependencies> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-web</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-jdbc</artifactid> </dependency> <dependency> <groupid>mysql</groupid> <artifactid>mysql-connector-java</artifactid> <scope>runtime</scope> </dependency> <dependency> <groupid>com.alibaba</groupid> <artifactid>druid</artifactid> <version>1.0.29</version> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-data-jpa</artifactid> </dependency> <!-- 这个是官方的mybatis依赖，这个你不加没法用噻 --> <dependency> <groupid>org.mybatis.spring.boot</groupid> <artifactid>mybatis-spring-boot-starter</artifactid> <version>1.3.2</version> </dependency> <!-- 这个是自动生成mapper等的依赖，必须得加--> <dependency> <groupid>org.mybatis.generator</groupid> <artifactid>mybatis-generator</artifactid> <version>1.3.5</version> <type>pom</type> </dependency> <!--这个是自动生成mapper等的依赖，必须得加 https://mvnrepository.com/artifact/org.mybatis.generator/mybatis-generator-core --> <dependency> <groupid>org.mybatis.generator</groupid> <artifactid>mybatis-generator-core</artifactid> <version>1.3.5</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-maven-plugin</artifactid> </plugin> <plugin> <groupid>org.mybatis.generator</groupid> <artifactid>mybatis-generator-maven-plugin</artifactid> <version>1.3.2</version> <configuration> <!--配置文件存放的地址--> <!--<configurationfile>src/main/resources/mybatis-generator/generatorconfig.xml</configurationfile>--> <verbose>true</verbose> <overwrite>true</overwrite> </configuration> </plugin> </plugins> </build>

2.在application.properties配置文件中进行数据库和mybatis扫描的配置

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 spring.datasource.driver-class-name=com.mysql.jdbc.driver spring.datasource.url=jdbc:mysql://localhost:3306/yddy?useunicode=true&characterencoding=utf-8&servertimezone=utc spring.datasource.username=root spring.datasource.password=123456 mybatis.config-locations=classpath:mybatis-config.xml # mapper文件 mybatis.mapper-locations=classpath:mapper/*.xml #这里直接写*，对后面自定义sql，编写xxxext.xml有好处，自动扫描到这些文件，不用再改配置了 mybatis.type-aliases-package=com.dameiweb.learn.model logging.level.com.dameiweb.learn.dao=debug #mybatis.config = mybatis 配置文件名称 #mybatis.mapperlocations = mapper xml 文件地址 #mybatis.typealiasespackage = 实体类包路径 #mybatis.typehandlerspackage = type handlers 处理器包路径 #mybatis.check-config-location = 检查 mybatis 配置是否存在，一般命名为 mybatis-config.xml #mybatis.executortype = 执行模式。默认是 simple

3.mybatis的配置和自动生成mapper的配置

在resource目录下新建一个generatorconfig.xml和mybatis-config.xml。内容如下：

generatorconfig.xml内容

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 <?xml version="1.0" encoding="utf-8"?> <!doctype generatorconfiguration public "-//mybatis.org//dtd mybatis generator configuration 1.0//en" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"> <generatorconfiguration> <classpathentry location="c:\users\nick\.m2\repository/mysql/mysql-connector-java/5.1.46/mysql-connector-java-5.1.46.jar"/> <context id="db2tables" targetruntime="mybatis3"> <commentgenerator> <property name="suppressdate" value="true"/> <property name="suppressallcomments" value="true"/> </commentgenerator> <!--数据库链接地址账号密码--> <jdbcconnection driverclass="com.mysql.jdbc.driver" connectionurl="jdbc:mysql://localhost:3306/yddy?useunicode=true&characterencoding=utf-8&servertimezone=utc" userid="root" password="123456"> </jdbcconnection> <javatyperesolver> <property name="forcebigdecimals" value="false"/> </javatyperesolver> <!--生成model类存放位置--> <javamodelgenerator targetpackage="com.dameiweb.learn.model" targetproject="src/main/java"> <property name="enablesubpackages" value="true"/> <!-- 从数据库返回的值被清理前后的空格 --> <property name="trimstrings" value="false"/> </javamodelgenerator> <!--生成映射文件存放位置--> <sqlmapgenerator targetpackage="mapper" targetproject="src/main/resources"> <property name="enablesubpackages" value="true"/> </sqlmapgenerator> <!--生成dao类存放位置--> <!-- 客户端代码，生成易于使用的针对model对象和xml配置文件 的代码 type="annotatedmapper",生成java model 和基于注解的mapper对象 type="mixedmapper",生成基于注解的java model 和相应的mapper对象 type="xmlmapper",生成sqlmap xml文件和独立的mapper接口 --> <javaclientgenerator type="xmlmapper" targetpackage="com.dameiweb.learn.dao" targetproject="src/main/java"> <property name="enablesubpackages" value="true"/> </javaclientgenerator> </context> </generatorconfiguration>

mybatis-config.xml的内容：

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 <?xml version="1.0" encoding="utf-8" ?> <!doctype configuration public "-//mybatis.org//dtd config 3.0//en" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <settings> <setting name="callsettersonnulls" value="true"/> <setting name="cacheenabled" value="true"/> <setting name="lazyloadingenabled" value="true"/> <setting name="aggressivelazyloading" value="true"/> <setting name="multipleresultsetsenabled" value="true"/> <setting name="usecolumnlabel" value="true"/> <setting name="usegeneratedkeys" value="false"/> <setting name="automappingbehavior" value="partial"/> <setting name="defaultexecutortype" value="simple"/> <setting name="mapunderscoretocamelcase" value="true"/> <setting name="localcachescope" value="session"/> <setting name="jdbctypefornull" value="null"/> </settings> <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>

这样我们就配置好了spring boot和mybatis与mybatis自动生成mapper和实体的功能。这样我们要生成某个表的实体和mapper的时候，只需要在generatorconfig.xml中javaclientgenerator标签之后添加下面的内容即可。

此处我们已yd_movies表为例(主要数据库表名字不要用复数，这个表名肯定是我之前脑子抽了，搞个复数的名字)

? 1 2 3 4 5 6 7 8 9 10 11 12 13 <!--生成对应表及类名--> <table tablename="yd_movies" domainobjectname="movie" enablecountbyexample="false" enableupdatebyexample="false" enabledeletebyexample="false" enableselectbyexample="false" selectbyexamplequeryid="false"> <columnoverride column="cover_photos" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="cover_photos_loc" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="pubdates" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="photographs_origin" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="photographs_origin_loc" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="languages" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="awards" javatype="java.lang.string" jdbctype="varchar" /> <columnoverride column="summary" javatype="java.lang.string" jdbctype="varchar" /> </table> <!--columnoverride使用这个标签是为了防止数据库字段类型为text时候，mybatis会生成xxxxwithblobs文件。-->

然后点击idea右侧maven projects，就可以看到mybatis-generate下的mybatis-generate：generate，双击mybatis-generate：generate即可。

**generator 注意点，也可以说是bug

就是在生成的时候，在第二次生成的时候，dao 和entity 都会直接覆盖，而mapper.xml 会直接追加，导致运行报错，而且很难找。**

4.mybatis自定义sql

当我们需要自定义sql的时候，我们不能把这些也放到mapper文件中。不然，当数据库表的字段有更新需要重新生成mapper的时候，这样我们自定义的sql不就被覆盖没了么！所以我们需要在moviemapper.xml的同级目录里，新建一个moviemapperext.xml文件，把自定义的sql放到这里，例子如下：

moviemapperext.xml文件内容

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 <?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.dameiweb.learn.dao.moviemapper" > <select id="selectbycondition" resultmap="baseresultmap" parametertype="com.dameiweb.learn.dto.movierequest"> select yd_movies.* from yd_movies left join yd_r_movie_countries on yd_movies.id = yd_r_movie_countries.movie_id left join yd_countries cou on yd_r_movie_countries.country_id = cou.id left join yd_r_movie_category on yd_movies.id = yd_r_movie_category.movie_id left join yd_category cat on yd_r_movie_category.category_id = cat.id left join yd_r_movie_actor on yd_movies.id = yd_r_movie_actor.movie_id left join yd_actors a on yd_r_movie_actor.actor_id = a.id where yd_movies.status = 1 <if test="movierequest.title != null"> and yd_movies.title like "%"#{movierequest.title}"%" </if> <if test="movierequest.country != null"> and cou.id = #{movierequest.country} </if> <if test="movierequest.category != null"> and cat.id = #{movierequest.category} </if> <if test="movierequest.year != null"> and year = #{movierequest.year} </if> <if test="movierequest.rate != null"> and rate >= #{movierequest.rate} </if> <if test="movierequest.rate != null"> and rate < (#{movierequest.rate}+1) </if> <if test="movierequest.subtype != null"> and yd_movies.subtype = #{movierequest.subtype} </if> group by yd_movies.id order by updated_at desc, year </select> </mapper>

总结

以上所述是小编给大家介绍的spring boot整合mybatis并自动生成mapper和实体，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！

原文链接：https://www.ydstudio.net/archives/54.html