mybatis培训教程尚MyBatis是支持普通SQL查询存储过程和高级映射的优秀

———————————————————————————————题目：Mybatis培训，MyBatis是支持普通SQL查询过程和高级映射的优秀持久层框架MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装。MyBatis可以使用简单的XML或注解用于配置和原始映射JavaPOJO（inOldJavaObjects，普通Java对象），JDBC-→dbutils-→MyBatis-编写第一个基于mybaits的测试例子【【mybatismybatis-【MYSQL驱动包mysql-connector-java-5.1.7-useCREATETABLEuseCREATETABLEusers(idINTPRIMARYKEYAUTO_INCREMENT,NAMEVARCHAR(20),ageINT);INSERTINTOusers(NAME,age)VALUES('Tom',12);<!DOCTYPEconfigurationPUBLIC"-////DTDConfig3.0//EN" publicpublicclass{privateintid;privateintage;}<selectid="getUser"parameterType="int"select*fromuserswhereid=#{id}" <mapper {Stringresource=Readerreader=//创建能执行映射文件中sql的sqlSessionStringstatement=//usersql}}XML的实insertintousers(name,age)values(#{name},#{age});deletefromuserswhereid=#{id}updateuserssetname=#{name},age=#{age}whereid=#{id}select*fromuserswhereid=#{id}select*fromusers2).2).在config.xml <mapper3).daoSqlSessionsession=sessionFactory.openSession();Useruser=session.selectOne(URI+".selectUser",id);returnuser;}注解的实@Insert("insertintousers(name,age)values(#{name},#{age})")publicintinsertUser(Useruser);publicintdeleteUserById(intid);@Update("updateuserssetname=#{name},age=#{age}whereid=#{id}")publicintupdateUser(Useruser);publicUsergetUserById(intid);@Select("select*fromusers")publicList<User>getAllUser();}2).2).在config <mapper3).daoSqlSessionsession=sessionFactory.openSession();Useruser=mapper.getUserById(id);}.####4.2.为实体类定义别名,简化sql映射xml文件中 .11.perties(方式一log4j.xml(方式二 (%F:%L)\n"<logger<loggerorder_idINTPRIMARYKEYorder_priceFLOATINSERTINTOorders(order_no,order_price)VALUES('aaaa',23);INSERTINTOorders(order_no,order_price)VALUES('bbbb',33);INSERTINTOorders(order_no,order_price)VALUES('cccc',22);{privateint}}方式一方式一:通过在sql语句中定义别方式二:通过select*fromorderswhereorder_id=#{id}一对一关根据班级id查询班级信息(带老师的信息t_idINTPRIMARYKEYt_namec_idINTPRIMARYKEYteacher_idINTALTERTABLEclassADDCONSTRAINTfk_teacher_idFOREIGNKEY(teacher_id)REFERENCESINSERTINTOteacher(t_name)VALUES('LS1');INSERTINTOclass(c_name,teacher_id)VALUES('bj_a',1);publicpublicclass{privateintid;}publicclass{privateintid;} <selectid="getClass"parameterType="int"resultMap="ClassResultMap">select*fromclassc,teachertwherec.teacher_id=t.t_idandc.c_id=#{id}SELECT*FROMclassWHERESELECT*FROMteacherWHERE //1是上一个查询得到的teacher_idselect*fromclasswhereSELECTt_idid,t_namenameFROMteacherWHEREpublicvoidtestOO()SqlSessionsqlSession=}SqlSessionsqlSession=}一对多关根据 查询对应的班级信息,包括学生,老s_idINTPRIMARYKEYclass_idINTINSERTINTOstudent(s_name,class_id)VALUES('xs_A',1);INSERTINTOstudent(s_name,class_id)VALUES('xs_B',1);INSERTINTOstudent(s_name,class_id)VALUES('xs_C',1);INSERTINTOstudent(s_name,class_id)VALUES('xs_D',2);INSERTINTOstudent(s_name,class_id)VALUES('xs_E',2);INSERTINTOstudent(s_name,class_id)VALUES('xs_F',2);publicpublicclass{privateintid;}publicclassClassesprivateintid;privateintid;privateTeacherteacher;privateList<Student>students;}方式一:嵌套结果: select*fromclassc,teachert,studentswherec.teacher_id=t.t_idandc.C_id=s.class_idandSELECT*FROMclassWHERESELECT*FROMteacherWHERE //1是上一个查询得到的teacher_idSELECT*FROMstudentWHERE select*fromclasswherec_id=#{id} SELECTt_idid,t_namenameFROMteacherWHEREt_id=#{id}SELECTs_idid,s_namenameFROMstudentWHERESqlSessionsqlSession=}SqlSessionsqlSession=}提出需求实现多条件查询用户(模糊匹配,在指定的最小值到最大值之间准备数据表和数据idintprimarykeyauto_increment,namevarchar(10),ageinsertintod_user(name,age)values('Tom',12);insertintod_user(name,age)values('Bob',13);insertintod_user(name,age)values('Jack',18);privateintminAge;privateintprivateintid;privateintid;privateintage;<!DOCTYPEmapperPUBLIC"-////DTDMapper3.0//EN" <mapper<selectid="getUser"parameterType="com.atguigu.day03_mybatis.test6.ConditionUser"select*fromd_userwhereage>=#{minAge}andReaderreader=SqlSessionsqlSession=sessionFactory.openSession();Stringstatement=List<User>list=sqlSession.selectList(statement,newConditionUser("%a%",1,12));}}提出需求查询得到或女性的数量,如果传入的是0就女性否则是准备数据库表和过程idintprimarykeyauto_increment,namevarchar(10),insertintop_user(name,)values('A',"男");insertintop_user(name,)values('B',"女");insertintop_user(name,)values('C',"男");#或女性的数量,0)DELIMITERCREATEPROCEDUREmybatis.ges_user_count(IN _id=0SELECTCOUNT(*)FROMmybatis.p_userWHEREp_user. SELECTCOUNT(*)FROMmybatis.p_userWHEREp_user. ENDIF;$DELIMITERSET@user_count=SELECT@user_count;publicpublicclass{privateStringid;privateString }<mapper<mapper p=new _id",ObjectreturnValue=sqlSession.selectOne(statement,par 一级缓存:基于PerpetualCache的HashMap本地缓存，其作用一级缓存:基于PerpetualCache的HashMap本地缓存，其作用域为Session，当Sessionflush或close之后，该Session中的所有Cache就将清空。二级缓存与一级缓存其机制相同，默认也是采用PerpetualCache，HashMap 其作用域为Mapper(Namespace)，并且可自定义源，如Ehcache。C/U/Dselect中的缓存将被clear1)提出需求idINTPRIMARYKEYAUTO_INCREMENT,NAMEVARCHAR(20),ageINSERTINTOc_user(NAME,age)VALUES('Tom',12);INSERTINTOc_user(NAME,age)VALUES('Jack',11);publicpublicclassUserimplementsprivateintid;privateintage;}"<mapperselect*fromc_userwhere测试*一级缓存:Session级的缓存(默认开启SqlSessionsession=Useruser=session.selectOne(statement,1);*session=MybatisUtils.getSession();4.没有执行过增删改的操作(这些操作都会清理缓存newUser(2,"user",23));}<mapper<mapper*Stringstatement=SqlSessionsession=MybatisUtils.getSession();Useruser=session.selectOne(statement,1);user=session2.selectOne(statement,1);}根据时间表（比如no 缓存会列表集合或对象（无论查询方法返回什么）的1024个 size="512"//最多缓存512个 "/>//user_birthdayDATE,user_salaryDOUBLE)编码实体类:publicpublicclassUserprivateintid;privateStringname;privateDatebirthday;privatedouble}DAO接口UserMapperpublicpublicinterfaceUserMappervoidsave(Useruser);voidupdate(Useruser);voiddelete(intid);UserfindById(intid);List<User>findAll();}SQL映射文件<!DOCTYPEmapperPUBLIC"-////DTDMapper3.0//EN" <mapper<!--insertintos_user(user_name,user_birthday,user_salary)updates_usersetuser