//转载请注明出处：

1.项目结构区别：

2.开发区别：

注：其中原始dao开发的实现类UserDaoImpl 与动态代理开发的工具类UserService的第16行-第27行代码可以提炼出来，

       每个逻辑方法里都要注入这6行代码，会有些繁琐，因此需要提炼出来作为一个工厂类，对外提供Sqlsession会话。

3.工厂类：Factory

1 public class Factory { 2     private final static Class
     
       lock = Factory.class; 3     private static SqlSessionFactory sqlSessionFactory = null; 4     private Factory() {} 5  6     public static SqlSessionFactory getSqlSessionFactory() { 7         synchronized (lock) { 8             if (sqlSessionFactory != null) { 9                 return sqlSessionFactory;10             }11             //加载核心配置文件12             String resource = "mybatis-config.xml";13             InputStream inputStream;14             try {15                 inputStream = Resources.getResourceAsStream(resource);16                 //创建SqlsessionFactory工厂17                 sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);18             } catch (IOException e) {19                 e.printStackTrace();20                 return null;21             }22             //对外提供一个工厂23             return sqlSessionFactory;24         }25     }26 27     //对外提供一个Sqlsession会话28     public static SqlSession getSession() {29         if (sqlSessionFactory == null) {30             getSqlSessionFactory();31         }32         return sqlSessionFactory.openSession();33     }34 }
     

工厂类使用示例：

4.Mybatis的核心配置文件：mybatis-config.xml

1 
      2  5  6 
     
       7     
       8  9     
      10     
      11     
       
       12         
          
        13             
         
        14             
           
         15                 
         16                 
         17                 
         18                 
         19             
        20         
       21     
      22 23     
      24     
      
       25         
       26         
       27         
       28         
       29         
       30         
       31     
      32 
     

5.外部属性文件：jdbc

1 jdbc.driver=com.mysql.jdbc.Driver2 jdbc.url=jdbc:mysql://localhost:3306/crud?useSSL=false&serverTimezone=UTC&characterEncoding=utf-83 jdbc.username=root4 jdbc.password=123456

6.日志文件：log4j

1 ### 设置Logger输出级别和输出目的地 ### debug更详细,如果把debug改为info，则打印出的表数据遇到字符串就不显示，此外还有log4j.log文件 2 log4j.rootLogger=debug,stdout 3          4 ### 把日志信息输出到控制台 ### 5 log4j.appender.stdout=org.apache.log4j.ConsoleAppender  6 #log4j.appender.stdout.Target=System.err 7 log4j.appender.stdout.layout=org.apache.log4j.SimpleLayout  8  9 ### 把日志信息输出到文件：log4j.log ###10 log4j.appender.logfile=org.apache.log4j.FileAppender 11 log4j.appender.logfile.File=log4j.log 12 log4j.appender.logfile.layout=org.apache.log4j.PatternLayout 13 log4j.appender.logfile.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %F %p %m%n14 15 ###显示SQL语句部分 ###16 #第一行：xml映射文件所在包17 log4j.logger.com.nreg.sqlMap=DEBUG18 log4j.logger.java.sql.Connection=DEBUG19 log4j.logger.java.sql.Statement=DEBUG20 log4j.logger.java.sql.PreparedStatement=DEBUG21 log4j.logger.java.sql.ResultSet=DEBUG

7.开发用crud模板：

1).接口：

1     //增 2     boolean addUser(User user); 3     //删 4     boolean deleteUserById(int id); 5     //改 6     boolean updateUserById(User user); 7     //查:按id查一个 8     User getUserById(int id); 9     //查:查所有10     List
     
       getUser();
     

2).xml映射文件：

         
     
              insert into user values(null,#{username},#{password})    
         
         
     
              delete from user where id = #{id}    
         
         
     
              update user set username = #{username},password = #{password} where id=#{id}    
         
                 select * from user where 1=1 and id = #{id}
              
                 select * from user    

3).动态代理开发：UserService工具类：

1 public class UserService {  2       3     SqlSession sqlsession=null;  4     //增  5     public boolean addUser(User user) {  6         try {  7             //1.通过工厂获取会话  8             sqlsession= Factory.getSession();  9             //2.从会话中获取接口的代理对象 10             UserMapper userMapper=sqlsession.getMapper(UserMapper.class); 11             //3.通过代理对象操作数据库 12             userMapper.addUser(user); 13             //提交事务 14             sqlsession.commit(); 15             return true; 16         } catch (Exception e) { 17             //回滚 18             if(sqlsession !=null){ 19                 sqlsession.rollback(); 20             } 21             return false; 22         }finally{ 23             //关闭连接,释放资源 24             if(sqlsession!=null){ 25                 sqlsession.close(); 26             } 27         } 28     } 29      30     //删 31     public boolean deleteUserById(int id) { 32         try { 33             sqlsession= Factory.getSession(); 34             UserMapper userMapper=sqlsession.getMapper(UserMapper.class); 35             boolean tf=userMapper.deleteUserById(id); 36             sqlsession.commit(); 37             return tf; 38         } catch (Exception e) { 39             if(sqlsession!=null){ 40                 sqlsession.rollback(); 41             } 42             return false; 43         }finally{ 44             if(sqlsession!=null){ 45                 sqlsession.close(); 46             } 47         } 48     } 49      50     //改 51     public boolean updateUserById(User user) { 52  53         try { 54             sqlsession= Factory.getSession(); 55             UserMapper userMapper=sqlsession.getMapper(UserMapper.class); 56             userMapper.updateUserById(user); 57             sqlsession.commit(); 58             return true; 59         } catch (Exception e) { 60             if(sqlsession !=null){ 61                 sqlsession.rollback(); 62             } 63             return false; 64         }finally{ 65             if(sqlsession !=null){ 66                 sqlsession.close(); 67             } 68         } 69     } 70  71     //查:按id查一个 72     public User getUserById(int id) { 73  74         try { 75             sqlsession= Factory.getSession(); 76             UserMapper userMapper=sqlsession.getMapper(UserMapper.class); 77             User user = userMapper.getUserById(id); 78             return user; 79  80         } catch (Exception e) { 81             if(sqlsession!=null){ 82                 sqlsession.rollback(); 83             } 84             e.printStackTrace(); 85             return null; 86         }finally{ 87             if(sqlsession !=null){ 88                 sqlsession.close(); 89             } 90         } 91     } 92  93     //查:查所有 94     public List
     
       getUser() { 95  96         try { 97             sqlsession = Factory.getSession(); 98             List
      
        list = null; 99             UserMapper userMapper=sqlsession.getMapper(UserMapper.class);100             list = userMapper.getUser();101             return list;102         } catch (Exception e) {103             if(sqlsession!=null){104                 sqlsession.rollback();105             }106             return null;107         }finally{108             if(sqlsession !=null){109                 sqlsession.close();110             }111         }112     }113 }
      
     

 

4).原始dao开发：UserDaoImpl实现类：

1 public class UserDaoImpl implements UserDao {  2   3     SqlSession sqlsession = null;  4     //增：  5     @Override  6     public boolean addUser(User user) {  7         try {  8             //1.通过工厂获取会话  9             sqlsession = Factory.getSession(); 10             //2.通过会话操作数据库 11             sqlsession.insert("addUser", user); 12             //提交事务:增删改都需要提交事务 13             sqlsession.commit(); 14             return true; 15         } catch (Exception e) { 16             //回滚 17             if (sqlsession != null) { 18                 sqlsession.rollback(); 19             } 20             return false; 21         } finally { 22             //关闭连接,释放资源 23             if (sqlsession != null) { 24                 sqlsession.close(); 25             } 26         } 27     } 28  29     //删 30     @Override 31     public boolean deleteUserById(int id) { 32         try { 33             //1.通过工厂获取会话 34             sqlsession = Factory.getSession(); 35             //2.通过会话操作数据库 36             sqlsession.delete("deleteUserById",id); 37             //3.提交事务 38             sqlsession.commit(); 39             return true; 40         } catch (Exception e) { 41             if (sqlsession != null) { 42                 //回滚 43                 sqlsession.rollback(); 44             } 45             return false; 46         } finally { 47             if (sqlsession != null) { 48                 //关闭连接，释放资源 49                 sqlsession.close(); 50             } 51         } 52     } 53  54  55     //改： 56     @Override 57     public boolean updateUserById(User user) { 58         try { 59             sqlsession = Factory.getSession(); 60             sqlsession.update("updateUserById", user); 61             sqlsession.commit(); 62             return true; 63         } catch (Exception e) { 64             if (sqlsession != null) { 65                 sqlsession.rollback(); 66             } 67             return false; 68         } finally { 69             if (sqlsession != null) { 70                 sqlsession.close(); 71             } 72         } 73     } 74      75     //查：按id查 76     @Override 77     public User getUserById(int id) { 78         try { 79             sqlsession = Factory.getSession(); 80             User user = sqlsession.selectOne("getUserById",id); 81             return user; 82         } catch (Exception e) { 83             if (sqlsession != null) { 84                 sqlsession.rollback(); 85             } 86             return null; 87         } finally { 88             if (sqlsession != null) { 89                 sqlsession.close(); 90             } 91         } 92     } 93  94     //查：查所有 95     @Override 96     public List
     
       getUser() { 97         try { 98             sqlsession = Factory.getSession(); 99             List
      
        list = sqlsession.selectList("getUser");100             return list;101         } catch (Exception e) {102             if (sqlsession != null) {103                 sqlsession.rollback();104             }105             return null;106         } finally {107             if (sqlsession != null) {108                 sqlsession.close();109             }110         }111     }112 }
      
     

结。