Mybatis学习笔记

1.初步搭建Mybatis

1.创建maven工程

 2.引入依赖

    
    
        org.mybatis
        mybatis
        3.5.7
    
    
    
        junit
        junit
        4.12
        test
    
    
    
        mysql
        mysql-connector-java
        5.1.3
    

3.创建Mybatis核心配置文件mybatis-config.xml

4.创建mapper接口

public interface CustomerMapper {
  
    List selectAll();

    int insert(Customer customer);

    Customer selectById(int id);

    int updateRelNameById(Customer customer);

    int  deleteById(int  id);

    List selectByCondition(Customer condition);
}

5.创建mybatis映射文件

    
    select id, name, tel, address, rel_name, other
    from db_quote.tb_customer
    
    
        select id, name, tel, address, rel_name , other
        from db_quote.tb_customer
        where id = #{id}
    
    
        select id, name, tel, address, rel_name, other
        from db_quote.tb_customer
        
            
                and name = #{name}
            
            
                and tel = #{tel}
            
            
                and address like #{address}
            
            
                and rel_name = #{relName}
            
            
                and other like #{other}
            
        
    
    
        insert into db_quote.tb_customer( name, tel, address, rel_name, other)
        VALUES(#{name},#{tel},#{address},#{relName},#{other})
    
    
        update db_quote.tb_customer
        set rel_name= #{relName}
        where id= #{id}
    

    
        delete from db_quote.tb_customer where id = #{id}
    

 

6. 加入log4J日志功能

1）加入依赖

log4j
log4j
1.2.17

2） 加入 log4j 的配置文件

2.Mybatis的增删查改 

1.添加数据

    
        insert into db_quote.tb_customer( name, tel, address, rel_name, other)
        VALUES(#{name},#{tel},#{address},#{relName},#{other})
    

2.删除数据

 
        delete from db_quote.tb_customer where id = #{id}
    

 3.查询数据

    
        select id, name, tel, address, rel_name, other
        from db_quote.tb_customer
    
    
        select id, name, tel, address, rel_name , other
        from db_quote.tb_customer
        where id = #{id}
    

4.修改数据

    
        update db_quote.tb_customer
        set rel_name= #{relName}
        where id= #{id}
    

3.Mybatis获取数据的方式 

1.MyBatis 获取参数值的两种方式:${}和 #{}

2.${}的本质就是字符串拼接,#{}的本质就是占位符赋值

3.${}使用字符串拼接的方式拼接 sql,若为字符串类型或日期类型的字段进行赋值时,需要手动加单引号;但是 #{}使用占位符赋值的方式拼接sql.此时为字符串类型或日期类型的字段进行赋值时，可以自动添加单引号