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課程計1、mybatis2、MybatisjdbcMybatisMybatis3、Daodao動態(tài)方1、輸入和輸出輸入?yún)?shù)返回值4、MybatisMyBatis介MyBatis本是apache的一個開源項目iBatis,2010年這個項目由apachesoftwarefoundation遷移到了code，并且改名為MyBatis。2013年11月遷移到。只需要關(guān)注SQL本身，而不需要花費精力去處理例如驅(qū)動、創(chuàng)建connection、創(chuàng)建進(jìn)行生成最終執(zhí)行的sql語句，最后由mybatis框架執(zhí)行sql并將結(jié)果成java對象并mysql先導(dǎo)入創(chuàng)建數(shù)據(jù)庫的sql導(dǎo)入到數(shù)據(jù)庫中eclipsemars1、創(chuàng)建一個java2jarmysqljdbc23jdbcstatement對象4sql語句5sql語句中的參數(shù)(6statementsql7sqljdbcpublicpublicstaticvoidmain(String[]args){Connectionconnection=PreparedStatementpreparedStatement=null;ResultSetresultSet=null;tryconnection=terEncoding=utf-8","root","root");//定義sql?Stringsql="select*fromuserwhereusername=preparedStatement=preparedStatement.setString(1, resultSet=preparedStatement.executeQuery();}}catch(Exceptione){ try}catch(SQLExceptione)//TODOAuto-generatedcatchblock}}try{}catch(SQLExceptione)//TODOAuto-generatedcatchblock}}try{}catch(SQLExceptione)//TODOAuto-generatedcatchblock}}}}上邊使用jdbc的原始方法（封裝）實現(xiàn)了查詢數(shù)據(jù)庫表記錄的操作jdbc2、Sql語句在代碼中硬編碼，造成代碼不易，實際應(yīng)用sql變化的可能較大，sql變動需要改變java代碼。3preparedStatementsqlwhere條件不一定，可能多也可能少，修改sql還要修改代碼，系統(tǒng)不易。4、對結(jié)果集解析存在硬編碼（查詢列名），sql變化導(dǎo)致解析代碼變化，系統(tǒng)不易，pojo對象解析比較方便。Mybatis架Mapper11mybatismapper.xml文件即sql文件，文件中配置了操作數(shù)據(jù)庫的sql語句。此文件需要在SqlMapConfig.xml中加載。5MappedStatementmybatismybatissql信息等。mapper.xmlsqlMappedStatement對象，sqlid即Mappedstatementid。pojoExecutor通過MappedStatement在執(zhí)行sql前將輸入的java對象至sql中，輸入?yún)?shù)就jdbcpreparedStatement設(shè)置參數(shù)。7MappedStatement對sqlHashMappojoExecutor通過MappedStatement在執(zhí)行sql后將輸出結(jié)果至java對象中輸出結(jié)果過Mybatis入門程mybatismybaits的代碼 idjavaeclipse創(chuàng)建java工程，jdk1.7.0_72jar加入mybatis包、依賴包、數(shù)據(jù)驅(qū)動包perties##Globalloggingconfigurationlog4j.rootLogger=DEBUG,stdout#Consoleoutput...log4j.appender.stdout=log4j.appender.stdout.layout=.apache.log4j.PatternLayoutlog4j.appender.stdout.layout.ConversionPattern=%5p[%t]-mybatislog4j<?xml<?xmlversion="1.0"encoding="UTF-8"<!DOCTYPEPUBLIC"-PUBLIC"-"http://DTDConfig和springenvironments<environments<environment使用jdbc事務(wù)管理<transactionManagertype="JDBC"數(shù)據(jù)庫連接池<dataSource<propertyname="driver"value="com.mysql.jdbc.Driver"/><propertyname="url"tf-8"/><propertyname="username"value="root"<propertyname="password"value="root"第五步：poPublicPublicclassUserprivateintprivateStringusername;/privateStringprivateDatebirthday;/privateStringaddress;/第六步：sql文在classpath下的 下創(chuàng)建sql文件<?xml<?xmlversion="1.0"encoding="UTF-8"<!DOCTYPEPUBLIC"-"<mapper//DTDMapper第七步：加載文mybatis框架需要加載文件，將Users.xml添加在SqlMapConfig.xml，如下<mapperid 根據(jù)id<selectid="findUserById"parameterType="int" select*fromuserwhereid=publicpublicclass{privateSqlSessionFactorypublicvoidcreateSqlSessionFactory()throwsIOExceptionStringresource=//sqlSessionFactory=new}id查詢用戶信息publicvoidtestFindUserById()SqlSessionsqlSession=null;try{創(chuàng)建數(shù)據(jù)庫會話實例sqlSession=查詢單個記錄，根據(jù)用戶idUseruser=}catch(Exceptione){}finallyif(sqlSession!=null){}}}}<select<selectid="findUserByUsername"parameterType="java.lang.String" select*fromuserwhereusernamelikeparameterType：定義輸入到sql中的 resultType：定義結(jié)果類型publicvoidtestFindUserByUsername()SqlSessionsqlSession=null;try{創(chuàng)建數(shù)據(jù)庫會話實例sqlSession=查詢單個記錄，根據(jù)用戶idList<User>list=sqlSession.selectList("test.findUserByUsername張");}catch(Exceptione){}finallyif(sqlSession!=null){}}}#{}和#{}#{}preparedStatementjavajdbc類型轉(zhuǎn)換，#{}sql#{}pojo屬性值。parameterType傳輸單個簡單類型值，#{}value或其它名稱。${}sql串，通過${}parameterTypesql中且不進(jìn)行jdbc類${}pojoparameterType傳輸單個簡單類型值，resultType：指定輸出結(jié)果類型，mybatis將sql查詢結(jié)果的一行記錄數(shù)據(jù)為selectOne(ornull)tobereturnedbyselectOne(),butfound:3<insertid="insertUser"insertintopublicvoidtestInsert()SqlSessionsqlSession=null;try{創(chuàng)建數(shù)據(jù)庫會話實例sqlSession=Useruser=newUser(); }catch(Exceptione){}finallyif(sqlSession!=null){}}}mysql<insertid="insertUser" selectKey<insertid="insertUser" selectKey<selectKeykeyProperty="id"order="AFTER"selectinsertintouser(username,birthday,sex,address)insertselectKeyafterMysqluuidselectuuid()uuid <selectKeyresultType="java.lang.String"order="BEFORE"selectinsertintouser(id,username,birthday,sex,address)<deleteid="deleteUserById"parameterType="int">deletefromuserwhereid=#{id}根據(jù)idpublicvoidtestDelete()SqlSessionsqlSession=null;try{創(chuàng)建數(shù)據(jù)庫會話實例sqlSession=}catch(Exceptione){}finallyif(sqlSession!=null){}}}<updateid="updateUser"updateuserwhere//更新用戶信 publicvoidtestUpdate()SqlSessionsqlSession=null;try{創(chuàng)建數(shù)據(jù)庫會話實例sqlSession=Useruser=newUser(); }catch(Exceptione){}finallyif(sqlSession!=null){}}}Mybatisjdbc2、Sql語句寫在代碼中造成代碼不易，實際應(yīng)用sql變化的可能較大，sql變動需要改java代碼。解決：將Sql語句配置在Xmapper.xml文件中與java代碼分離3sqlsqlwhere條件不一定，可能多也可能少，占位符解決：Mybatis自動將java對象至sql語句，通過statement中的parameterType定4sql變化導(dǎo)致解析代碼變化，且解析前需要遍歷，如果能將數(shù)據(jù)庫pojo對象解析比較方便。解決：Mybatis自動將sql執(zhí)行結(jié)果至java對象，通過statement中的resultTypemybatishibernateMybatishibernateORMMyBatis需要程序員自己編寫SqlmybatisXML或注解方式靈活配置要運行的sqljava對象和sql語句生成最終執(zhí)行的sql，最后將sql執(zhí)行的結(jié)果再生成java對象。靈活度高，非常適合對關(guān)系數(shù)據(jù)模型要求不高的開發(fā)，例如互聯(lián)網(wǎng)、企業(yè)運營類軟件等，因為這類需求變化頻繁，一但需求變化要求成果輸出迅速。但是靈活的前提是mybatis無法做到數(shù)據(jù)庫無關(guān)性如果需要實現(xiàn)支持多種數(shù)據(jù)庫的則需要自定義多套sql的學(xué)習(xí)門檻高，要精通門檻更高，而且怎么設(shè)計O/R，在性能和對象模型之間如何權(quán)Hibernate需要具有很強的經(jīng)驗和能力才行。Dao開發(fā)方MybatisDaoDaoMapperidSqlSessionSqlSessionFactoryBuilderSqlSessionSqlSessionFactory生產(chǎn)，所以可以SqlSessionFactory是一個接口，接口中定義了openSession的不同重載方法，SqlSessionFactory的最佳使用范圍是整個應(yīng)用運行期間，一旦創(chuàng)建后可以重復(fù)使用，通常以SqlSessionFactory。SqlSessionsqlSessionSqlSession實例。SqlSession的實例不能共享使用，它也是SqlSessionsession=sqlSessionFactory.openSession();try{//SqlSessionsession=sqlSessionFactory.openSession();try{//do}finally}DaoDaoDaoDao<?xml<?xmlversion="1.0"encoding="UTF-8"<!DOCTYPEPUBLIC"- //DTDMapper <mapper根據(jù)id<selectid="findUserById"parameterType="int" select*fromuserwhereid=<insertid="insertUser" <selectKeykeyProperty="id"order="AFTER"selectinsertintouser(username,birthday,sex,address)DaoPublicPublicinterfaceUserDaopublicUsergetUserById(intid)throwspublicvoidinsertUser(Useruser)throws}PublicclassUserDaoImplimplementsUserDaopublicUserDaoImpl(SqlSessionFactory}privateprivateSqlSessionFactorysqlSessionFactory;publicUsergetUserById(intid)throwsException{SqlSessionsession=sqlSessionFactory.openSession();Useruser=null;try數(shù)user=session.selectOne("test.findUserById",1);}}return}PublicvoidinsertUser(Useruser)throwsException{SqlSessionsqlSession=sqlSessionFactory.openSession();try{sqlSession.insert("insertUser",}}}}DaoprivateSqlSessionFactorypublicvoidinit()throwsprivateSqlSessionFactorypublicvoidinit()throwsExceptionSqlSessionFactoryBuildersessionFactoryBuilder=newSqlSessionFactoryBuilder();InputStreaminputStream=Resources.getResourceAsStream("SqlMapConfig.xml");sqlSessionFactory=sessionFactoryBuilder.build(inputStream);}publicvoidtestGetUserById()UserDaouserDao=newUserDaoImpl(sqlSessionFactory);Useruser=userDao.getUserById(22);}}DaoMapper動態(tài)方框架根據(jù)接口定義創(chuàng)建接口的動態(tài)對象，對象的方法體同上邊Dao接口實現(xiàn)類方2Mapper接口方法名和Mapper.xmlstatementid3Mappermapper.xmlsqlparameterType的4Mapper接口方法的輸出參數(shù)類型和mapper.xml中定義的每個sql的resultType的類型相定義mapper文件UserMapper.xml（內(nèi)容同Users.xml），需要修改namespace的值為UserMapper接口路徑。將UserMapper.xml放在classpath下mapper <?xml<?xmlversion="1.0"encoding="UTF-8"<!DOCTYPEPUBLIC"-PUBLIC"-"<mapper//DTDMapper根據(jù)id<selectid="findUserById"parameterType="int" select*fromuserwhereid=<selectid="findUserByUsername"parameterType="java.lang.String" select*fromuserwhereusernamelike<insertid="insertUser" <selectKeykeyProperty="id"order="AFTER"selectinsertintouser(username,birthday,sex,address)*用戶管理PublicinterfaceUserMapperpublicUserfindUserById(intid)throwspublicvoidinsertUser(Useruser)throws}1Mapper接口方法名和Mapper.xmlstatementid2Mapper接口方法的輸入?yún)?shù)類型和mapper.xml中定義的statementparameterType3Mapper接口方法的輸出參數(shù)類型和mapper.xml中定義的statement的resultType的類型<mapperPublicPublicclassUserMapperTestextendsTestCaseprivateSqlSessionFactoryprotectedvoidsetUp()throwsExceptionStringresource=sqlSessionFactory=new}PublicvoidtestFindUserById()throwsExceptionSqlSessionsession= 對UserMapperuserMapper= Useruser=userMapper.findUserById(1);}}publicvoidtestFindUserByUsername()throwsException{SqlSessionsqlSession=sqlSessionFactory.openSession();UserMapperuserMappersqlSession.getMapper(UserMapper.class);List<User>list=userMapper.findUserByUsername("張");}/r