[MyBatis日记]问题汇总

问题一：mybatis映射文件insert不执行，而直接用sql则可以插入成功

解决方案：

studentMapper.insertStudent(student);在执行晚SQL语句之后，记得session.commit();

问题二：中文显示乱码问题

解决方案：

配置数据库地址时加上编码格式characterEncoding： <property name="url" value="jdbc:mysql://localhost:3306/test?characterEncoding=utf8"/>

问题三：XML文件中大于号小于号问题

解决方案一： 用了转义字符把>和<替换掉

    
    
    
    

     
     
     
     
 
      <?xml version="1.0" encoding="UTF-8"?> 
     
     
     
     
     
 
      <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">  
     
     
     
     
     
 
      <mapper namespace="com.sjf.mapper.CourseMapper"> 
     
     
     
     
     
 
        
     
     
     
     
     
 
       <resultMap id = "CourseResultMap" type="com.sjf.bean.Course" > 
     
     
     
     
     
 
       <id property="ID" column="ID"/> 
     
     
     
     
     
 
       <result property="name" column="name"/> 
     
     
     
     
     
 
       <result property="desc" column="description"/> 
     
     
     
     
     
 
       <result property = "startDate" column = "startDate"/> 
     
     
     
     
     
 
       <result property = "endDate" column = "endDate"/> 
     
     
     
     
     
 
       </resultMap> 
     
     
     
     
     
 
        
     
     
     
     
     
 
       <select id="getCourseByCondation" parameterType="hashmap" resultMap="CourseResultMap">  
     
     
     
     
     
 
       SELECT * FROM Course  
     
     
     
     
     
 
       WHERE teacherID = #{teacherID}  
     
     
     
     
     
 
       <if test = "courseName != null" > 
     
     
     
     
     
 
       AND NAME = #{courseName} 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       <if test = "startDate != null"> 
     
     
     
     
     
 
       AND startDate >= #{startDate} 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       <if test = "endDate != null"> 
     
     
     
     
     
 
       AND endDate <= #{endDate} 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       </select> 
     
     
     
     
     
 
      </mapper>  
     
    
    
    
    

转义字符表：

转义符	符号
&lt;	<（小于号）
&gt;	>（大于号）
&amp;	&（和）
&apos;	'（单引号）
&quot;	"（双引号）

解决方案二：

因为这个是xml格式的，所以不允许出现类似“>”这样的字符，但是都可以使用<![CDATA[ ]]>符号进行说明，将此类符号不进行解析。

    
    
    
    

     
     
     
     
 
      <?xml version="1.0" encoding="UTF-8"?> 
     
     
     
     
     
 
      <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">  
     
     
     
     
     
 
      <mapper namespace="com.sjf.mapper.CourseMapper"> 
     
     
     
     
     
 
        
     
     
     
     
     
 
       <resultMap id = "CourseResultMap" type="com.sjf.bean.Course" > 
     
     
     
     
     
 
       <id property="ID" column="ID"/> 
     
     
     
     
     
 
       <result property="name" column="name"/> 
     
     
     
     
     
 
       <result property="desc" column="description"/> 
     
     
     
     
     
 
       <result property = "startDate" column = "startDate"/> 
     
     
     
     
     
 
       <result property = "endDate" column = "endDate"/> 
     
     
     
     
     
 
       </resultMap> 
     
     
     
     
     
 
        
     
     
     
     
     
 
       <select id="getCourseByCondation" parameterType="hashmap" resultMap="CourseResultMap">  
     
     
     
     
     
 
       SELECT * FROM Course  
     
     
     
     
     
 
       WHERE teacherID = #{teacherID}  
     
     
     
     
     
 
       <if test = "courseName != null" > 
     
     
     
     
     
 
       AND NAME = #{courseName} 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       <if test = "startDate != null"> 
     
     
     
     
     
 
       <![CDATA[AND startDate >= #{startDate} ]]> 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       <if test = "endDate != null"> 
     
     
     
     
     
 
       <![CDATA[AND endDate <= #{endDate} ]]> 
     
     
     
     
     
 
       </if> 
     
     
     
     
     
 
       </select> 
     
     
     
     
     
 
      </mapper>