springBoot中使用mybatis入门笔记（一）

　　前言：
　　这是一篇mybatis入门级别的文章，包含一些mybatis的配置，以及CRUD等。mybatis集成
　　1。引入依赖。在项目pom文件引入mybatis的相关依赖。如mysql驱动dependenciesdependencygroupIdmysqlgroupIdmysqlconnectorjavaartifactIdversion8。0。20versiondependencydependencygroupIdorg。mybatisgroupIdmybatisartifactIdversion3。5。5versiondependencydependencygroupIdorg。projectlombokgroupIdlombokartifactIdversion1。18。12versiondependencydependencygroupIdjunitgroupIdjunitartifactIdversion4。12versionscopetestscopedependencydependencygroupIdlog4jgroupIdlog4jartifactIdversion1。2。12versiondependencydependencies在项目resource文件夹下创建mybatisconfig。xml配置文件。lt；？xmlversion1。0encodingUTF8？！DOCTYPEconfigurationPUBLICmybatis。orgDTDConfig3。0ENhttp：mybatis。orgdtdmybatis3config。dtdconfigurationenvironmentsdefaultdevelopmentenvironmentiddevelopmenttransactionManagertypeJDBCdataSourcetypePOOLEDpropertynamedrivervaluecom。mysql。jdbc。Driverpropertynameurlvaluejdbc：mysql：localhost：3306eesy？serverTimezoneUTCuseSSLfalsepropertynameusernamevaluerootpropertynamepasswordvaluedcdell88dataSourceenvironmentenvironmentsmappersmapperresourceorgmybatisexampleBlogMapper。xmlmappersconfiguration编写一个Mybatis工具类获取sqlsessionpackagecom。keelon。Utils；importorg。apache。ibatis。io。Resources；importorg。apache。ibatis。session。SqlSession；importorg。apache。ibatis。session。SqlSessionFactory；importorg。apache。ibatis。session。SqlSessionFactoryBuilder；importjava。io。IOException；importjava。io。InputStream；publicclassMybatisUtils｛staticStringresource；privatestaticSqlSessionFactorysqlSessionFactory；static｛try｛Stringresourcemybatisconfig。xml；InputStreaminputStreamResources。getResourceAsStream（resource）；sqlSessionFactorynewSqlSessionFactoryBuilder（）。build（inputStream）；｝catch（IOExceptione）｛e。printStackTrace（）；｝｝publicstaticSqlSessiongetSqlSession（）｛returnsqlSessionFactory。openSession（）；｝｝创建实体类User。同时在数据库中创建一个与实体类对应的表。packagecom。keelon。entity；importlombok。Data；DatapublicclassUser｛privateIntegerid；privateStringname；privateStringpwd；｝
　　这里使用Data注解，用lombook帮我们自动生成set，get方法。
　　创建UserMapper的接口类。packagecom。keelon。mapper；importcom。keelon。entity。User；importjava。util。List；publicinterfaceUserMapper｛ListUserfindAll（）；｝
　　创建UserMapper的xml文件。lt；？xmlversion1。0encodingUTF8？！DOCTYPEmapperPUBLICmybatis。orgDTDMapper3。0ENhttp：mybatis。orgdtdmybatis3mapper。dtd！namespace绑定一个对应的Mapper接口mappernamespacecom。keelon。mapper。UserMapper！配置查询所有id为方法名resultType指定封装的实体类型selectidfindAllresultTypecom。keelon。entity。Userselectfromuserselectmapper
　　maven由于他的约定大于配置，我们之后可能会遇到我们写的配置文件，无法被导出或者生效的情况。下面是解决方案：buildresourcesresourcedirectorysrcmainresourcesdirectoryincludesinclude。propertiesincludeinclude。xmlincludeincludesfilteringtruefilteringresourceresourcedirectorysrcmainjavadirectoryincludesinclude。propertiesincludeinclude。xmlincludeincludesfilteringtruefilteringresourceresourcesbuild
　　最后我们编写一个单元测试类：
　　packagecom。keelon。dao；importcom。keelon。Utils。MybatisUtils；importcom。keelon。entity。User；importcom。keelon。mapper。UserMapper；importorg。apache。ibatis。session。SqlSession；importorg。junit。Test；importjava。util。List；publicclassdaoTest｛TestpublicvoidfindAllUser（）｛第一步获取sqlsessionSqlSessionsqlSessionMybatisUtils。getSqlSession（）；UserMapperuserMappersqlSession。getMapper（UserMapper。class）；ListUseruserListuserMapper。findAll（）；for（Useruser：userList）｛System。out。print（user。toString（））；｝｝｝
　　最后我们看看代码的结构和运行结果。