最近一直都在學習Java，發現目前Java招聘中，mybatis出現的頻率挺高的，可能是目前Java開發中使用比較多的數據庫ORM框架。於是我準備研究下Spring Boot和mybatis的整合。
1.在pom.xml文件中添加下面的配置
<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> <!-- 這個是官方的mybatis依賴，這個你不加沒法用噻--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <!-- 這個是自動生成mapper等的依賴，必須得加--> <dependency> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator</artifactId> <version>1.3.5</version> <type>pom</type> </dependency> <!--這個是自動生成mapper等的依賴，必須得加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配置文件中進行數據庫和mybatis掃描的配置
spring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.datasource.url=jdbc:mysql://localhost:3306/yddy?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTCspring.datasource.username=rootspring.datasource.password=123456mybatis.config-locations=classpath:mybatis-config.xml# mapper文件mybatis.mapper-locations=classpath:mapper/*.xml #這裡直接寫*，對後面自定義sql，編寫xxxExt.xml有好處，自動掃描到這些文件，不用再改配置了mybatis.type-aliases-package=com.dameiweb.learn.modellogging.level.com.dameiweb.learn.dao=debug#mybatis.config = mybatis 配置文件名稱#mybatis.mapperLocations = mapper xml 文件地址#mybatis.typeAliasesPackage = 實體類包路徑#mybatis.typeHandlersPackage = type handlers 處理器包路徑#mybatis.check-config-location = 檢查mybatis 配置是否存在，一般命名為mybatis-config.xml#mybatis.executorType = 執行模式。默認是SIMPLE
3.mybatis的配置和自動生成mapper的配置
在resource目錄下新建一個generatorConfig.xml和mybatis-config.xml。內容如下：
generatorConfig.xml內容
<?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> <!--數據庫鏈接地址賬號密碼--> <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類存放位置--> <javaModelGenerator targetPackage="com.dameiweb.learn.model" targetProject="src/main/java"> <property name="enableSubPackages" value="true"/> <!-- 從數據庫返回的值被清理前後的空格--> <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類存放位置--> <!-- 客戶端代碼，生成易於使用的針對Model對象和XML配置文件的代碼type="ANNOTATEDMAPPER",生成Java Model 和基於註解的Mapper對象type="MIXEDMAPPER",生成基於註解的Java Model 和相應的Mapper對象type="XMLMAPPER",生成SQLMap XML文件和獨立的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的內容：
<?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>
這樣我們就配置好了Spring Boot和mybatis與mybatis自動生成mapper和實體的功能。這樣我們要生成某個表的實體和mapper的時候，只需要在generatorConfig.xml中javaClientGenerator標籤之後添加下面的內容即可。
此處我們已yd_movies表為例(主要數據庫表名字不要用複數，這個表名肯定是我之前腦子抽了，搞個複數的名字)
<!--生成對應表及類名--> <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使用這個標籤是為了防止數據庫字段類型為text時候，mybatis會生成xxxxWithBLOBs文件。 -->
然後點擊idea右側Maven projects，就可以看到mybatis-generate下的mybatis-generate：generate，雙擊mybatis-generate：generate即可。
**generator 注意點，也可以說是BUG
就是在生成的時候，在第二次生成的時候，dao 和entity 都會直接覆蓋，而Mapper.xml 會直接追加，導致運行報錯，而且很難找。 **
4.mybatis自定義sql
當我們需要自定義sql的時候，我們不能把這些也放到mapper文件中。不然，當數據庫表的字段有更新需要重新生成mapper的時候，這樣我們自定義的sql不就被覆蓋沒了麼！所以我們需要在MovieMapper.xml的同級目錄裡，新建一個MovieMapperExt.xml文件，把自定義的sql放到這裡，例子如下：
MovieMapperExt.xml文件內容
<?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>總結
以上所述是小編給大家介紹的Spring Boot整合mybatis並自動生成mapper和實體，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對武林網網站的支持！