网站建设兼职在哪找,南通做外贸网站,wordpress内存不足,网络直播网站开发查询语句是使用 MyBatis 时最常用的元素之一select元素配置细节如下属性描述取值默认id在这个模式下唯一的标识符#xff0c;可被其它语句引用parameterType传给此语句的参数的完整类名或别名resultType语句返回值类型的整类名或别名。注意#xff0c;如果是集合#xff0c;…查询语句是使用 MyBatis 时最常用的元素之一select元素配置细节如下属性描述取值默认id在这个模式下唯一的标识符可被其它语句引用parameterType传给此语句的参数的完整类名或别名resultType语句返回值类型的整类名或别名。注意如果是集合那么这里填写的是集合的项的整类名或别名而不是集合本身的类名。(resultType 与resultMap 不能并用)resultMap引用的外部resultMap 名。结果集映射是MyBatis 中最强大的特性。许多复杂的映射都可以轻松解决。(resultType 与resultMap 不能并用)flushCache如果设为true则会在每次语句调用的时候就会清空缓存。select 语句默认设为falsetrue|falsefalseuseCache如果设为true则语句的结果集将被缓存。select 语句默认设为false true|false falsetimeout 设置驱动器在抛出异常前等待回应的最长时间默认为不设值由驱动器自己决定true|falsefalsetimeout设置驱动器在抛出异常前等待回应的最长时间默认为不设值由驱动器自己决定正整数未设置fetchSize设置一个值后驱动器会在结果集数目达到此数值后激发返回默认为不设值由驱动器自己决定正整数驱动器决定statementTypestatementpreparedstatementcallablestatement。预准备语句、可调用语句STATEMENTPREPAREDCALLABLEPREPAREDresultSetTypeforward_onlyscroll_sensitivescroll_insensitive只转发滚动敏感不区分大小写的滚动FORWARD_ONLYSCROLL_SENSITIVESCROLL_INSENSITIVE驱动器决定例子1 ?xml version1.0 encodingUTF-8?2 /p4 http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd5 6 7 keyPropertyclassId8 INSERT INTO users(username,PASSWORD)9 VALUES(#{username},#{password});10 11 12 resultMapadminResultMap13 SELECT *FROM t_admin;14 1516 17 18 19 20 21 28 29 下面是常用的增删查改方法1)configuration.xml MyBatis主配置文件1 ?xml version1.0 encodingUTF-8?2 /p3 http://mybatis.org/dtd/mybatis-3-config.dtd45 6 7 8 910 11 12 13 14 1516 17 18 19 2021 22 23 24 25 26 27 28 29 30 31 32 3334 35 36 37 3839 2)jdbc.properties1 drivercom.mysql.jdbc.Driver2 urljdbc:mysql://localhost:3306/keith3 usernamekeith4 passwordkeith3)log4j.properties1 log4j.rootLoggerDEBUG,CONSOLE,FILEOUT2 log4j.addivity.org.apachetrue34 # CONSOLE5 log4j.appender.CONSOLEorg.apache.log4j.ConsoleAppender6 log4j.appender.ThresholdDEBUG7 log4j.appender.CONSOLE.TargetSystem.out8 log4j.appender.CONSOLE.layoutorg.apache.log4j.PatternLayout9 #log4j.appender.CONSOLE.layout.ConversionPattern[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n10 log4j.appender.CONSOLE.layout.ConversionPattern[%-5p] %d{yyyy-MM-dd HH\:mm\:ss} \:%m%n1112 #13 # FILEOUT14 log4j.appender.FILEOUTorg.apache.log4j.RollingFileAppender15 log4j.appender.FILEOUT.File${catalina.home}\\file.log16 log4j.appender.fileout.MaxFileSize100000KB17 # default is trueappend to the file; if false, the replace the log file whenever restart system18 log4j.appender.FILEOUT.Appendtrue19 #RollingFileAppender没有DatePattern这个属性20 log4j.appender.FILEOUT.layoutorg.apache.log4j.PatternLayout21 #log4j.appender.CONSOLE.layout.ConversionPattern[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n22 log4j.appender.FILEOUT.layout.ConversionPattern[%-5p]_%d{yyyy-MM-dd HH:mm:ss} :%m%n4)User .java1 packagecom.mybatis.model;23 importjava.io.Serializable;45 SuppressWarnings(serial)6 public class User implementsSerializable {78 private intid;9 privateString userName;10 privateString password;1112 publicUser(){13 }1415 public intgetId() {16 returnid;17 }18 public void setId(intid) {19 this.id id;20 }21 publicString getUserName() {22 returnuserName;23 }24 public voidsetUserName(String userName) {25 this.userName userName;26 }27 publicString getPassword() {28 returnpassword;29 }30 public voidsetPassword(String password) {31 this.password password;32 }3334 }5)UserSqlMap.xml1 ?xml version1.0 encodingUTF-8?2 /p4 http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd56 7 8 9 10 11 12 13 1415 16 17 userName,password18 1920 21 22 INSERT INTO USER() VALUES(#{userName},#{password})23 2425 26 UPDATE USER SET userName#{userName} ,password#{password} WHERE id#{id}27 2829 30 DELETE FROM USER WHERE id#{id}31 3233 34 SELECT *FROM USER35 3637 38 39 SELECT *FROM USER LIMIT #{pageNow},#{pageSize}40 4142 43 SELECT * FROM USER WHERE id#{id}44 4546 47 SELECT count(*) FROM USER48 4950 51 SELECT * FROM USER WHERE userName#{userName}52 5354 6)SessionFactoryUtil.java MyBatis工具类用于创建SqlSessionFactory1 packagecom.mybatis.sessionfactory;23 importjava.io.IOException;4 importjava.io.Reader;56 importorg.apache.ibatis.io.Resources;7 importorg.apache.ibatis.session.SqlSession;8 importorg.apache.ibatis.session.SqlSessionFactory;9 importorg.apache.ibatis.session.SqlSessionFactoryBuilder;1011 public classSessionFactoryUtil {1213 private static final String RESOURCE Configuration.xml;14 private static SqlSessionFactory sqlSessionFactory null;15 private static ThreadLocal threadLocal new ThreadLocal();1617 static{18 Reader reader null;19 try{20 reader Resources.getResourceAsReader(RESOURCE);21 } catch(IOException e) {22 throw new RuntimeException(Get resource error:RESOURCE, e);23 }2425 sqlSessionFactory newSqlSessionFactoryBuilder().build(reader);26 }2728 /**29 * Function : 获得SqlSessionFactory30 */31 public staticSqlSessionFactory getSqlSessionFactory(){32 returnsqlSessionFactory;33 }3435 /**36 * Function : 重新创建SqlSessionFactory37 */38 public static voidrebuildSqlSessionFactory(){39 Reader reader null;40 try{41 reader Resources.getResourceAsReader(RESOURCE);42 } catch(IOException e) {43 throw new RuntimeException(Get resource error:RESOURCE, e);44 }4546 sqlSessionFactory newSqlSessionFactoryBuilder().build(reader);47 }4849 /**50 * Function : 获取sqlSession51 */52 public staticSqlSession getSession(){53 SqlSession session threadLocal.get();5455 if(session!null){56 if(sqlSessionFactory null){57 getSqlSessionFactory();58 }59 //如果sqlSessionFactory不为空则获取sqlSession否则返回null60 session (sqlSessionFactory!null) ? sqlSessionFactory.openSession(): null;61 }6263 returnsession;64 }6566 /**67 * Function : 关闭sqlSession68 */69 public static voidcloseSession(){70 SqlSession session threadLocal.get();71 threadLocal.set(null);72 if(session!null){73 session.close();74 }75 }76 }7)UserDao interface1 packagecom.mybatis.dao;23 importjava.util.List;45 importcom.mybatis.model.User;67 public interfaceUserDao {89 public User load(intid);10 public voidadd(User user);11 public voidupdate(User user);12 public void delete(intid);13 publicUser findByName(String userName);14 public ListqueryAllUser();15 public List list(int pageNow,intpageSize);16 public intgetAllCount();1718 }8)UserDaoImpl1 packagecom.mybatis.dao.implment;23 importjava.util.HashMap;4 importjava.util.List;5 importjava.util.Map;67 importorg.apache.ibatis.session.SqlSession;89 importcom.mybatis.dao.UserDao;10 importcom.mybatis.model.User;11 importcom.mybatis.sessionfactory.SessionFactoryUtil;121314 public class UserDaoImpl implementsUserDao {1516 public User load(intid){17 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();18 User user (User) session.selectOne(com.mybatis.model.User.selectById_user, id);19 session.close();20 returnuser;21 }2223 public voidadd(User user) {24 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();25 session.insert(com.mybatis.model.User.inser_user, user);26 session.commit();27 session.close();28 }2930 public voidupdate(User user){31 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();32 session.update(com.mybatis.model.User.update_user, user);33 session.commit();34 session.close();35 }3637 public void delete(intid){38 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();39 session.delete(com.mybatis.model.User.delete_user, id);40 session.close();41 }4243 publicUser findByName(String userName){44 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();45 User user (User)session.selectOne(com.mybatis.model.User.selectByName_user, userName);46 session.close();47 returnuser;48 }4950 SuppressWarnings(unchecked)51 public ListqueryAllUser() {52 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();53 List list session.selectList(com.mybatis.model.User.selectAll_user);54 session.close();55 returnlist;56 }5758 SuppressWarnings(unchecked)59 public List list(int pageNow , intpageSize){60 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();61 Map params new HashMap();62 params.put(pageNow, pageNow);63 params.put(pageSize, pageSize);64 List list session.selectList(com.mybatis.model.User.selectList_user, params);65 session.close();66 returnlist;67 }6869 public intgetAllCount(){70 SqlSession session SessionFactoryUtil.getSqlSessionFactory().openSession();71 int count (Integer) session.selectOne(com.mybatis.model.User.selectCount_user);72 session.close();73 returncount;74 }7576 }9)测试类1 packagecom.mybatis.dao.implment;23 importjava.util.List;45 importorg.junit.Test;67 importcom.mybatis.dao.UserDao;8 importcom.mybatis.model.User;910 public classUserDaoTest {1112 private UserDao userDao newUserDaoImpl();1314 Test15 public voidtestLoad(){16 User u userDao.load(1);17 if(u!null){18 System.out.println(UserId:u.getId() UserName:u.getUserName() Password:u.getPassword());19 }20 else{21 System.out.println(id不存在);22 }23 }2425 Test26 public voidtestAdd(){27 User user newUser();28 user.setUserName(admin5);29 user.setPassword(123456);30 userDao.add(user);31 }3233 Test34 public voidtestUpdate(){35 User user newUser();36 user.setId(2);37 user.setUserName(manager);38 user.setPassword(123456);39 userDao.update(user);40 }4142 Test43 public voidtestQueryAllUser(){44 List list userDao.queryAllUser();45 if(list!nulllist.size()0){46 for(User u:list){47 System.out.println(UserId:u.getId() UserName:u.getUserName() Password:u.getPassword());48 }49 }50 }5152 Test53 public voidtestFindByName(){54 User u userDao.findByName(admin);55 if(u!null){56 System.out.println(UserId:u.getId() UserName:u.getUserName() Password:u.getPassword());57 }58 else{59 System.out.println(用户名不存在);60 }61 }6263 Test64 public voidtestList(){65 List list userDao.list(1, 4);66 if(list!nulllist.size()0){67 for(User u:list){68 System.out.println(UserId:u.getId() UserName:u.getUserName() Password:u.getPassword());69 }70 }71 }7273 Test74 public voidtestGetAllCount(){75 System.out.println(All Count : userDao.getAllCount());76 }7778 Test79 public voidtestDelete(){80 userDao.delete(3);81 }8283 }10)执行testFindByName()参考至http://www.open-open.com/lib/view/open1349622424072.html郁极风在此感谢这位同僚的帮助。
