- import java.util.HashMap;
- import java.util.LinkedHashMap;
- import java.util.List;
- import java.util.Map;
- import org.apache.ibatis.session.SqlSession;
- import cn.itcast.javaee.mybatis.util.MybatisUtil;
- /**
- * 持久层
- * @author AdminTC
- */
- public class StudentDao {
- /**
- * 有条件更新学生
- */
- public void dynaUpdate(Integer id,String name,Double sal) throws Exception{
- SqlSession sqlSession = null;
- try{
- sqlSession = MybatisUtil.getSqlSession();
- Map<String,Object> map = new HashMap<String, Object>();
- map.put("pid",id);
- map.put("pname",name);
- map.put("psal",sal);
- sqlSession.update("studentNamespace.dynaUpdate",map);
- sqlSession.commit();
- }catch(Exception e){
- e.printStackTrace();
- sqlSession.rollback();
- throw e;
- }finally{
- MybatisUtil.closeSqlSession();
- }
- }
- public static void main(String[] args) throws Exception{
- StudentDao dao = new StudentDao();
- // 关注 SQL 的变化
- //dao.dynaUpdate(1,null,9000D);//update students set sal=? where id=?
- //dao.dynaUpdate(1,"笨笨",null);//update students set name=? where id=?
- dao.dynaUpdate(1,"笨笨",10000D);//update students set name=? and sal=? where id=?
- }
- }
- <?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="studentNamespace">
- <resultMap type="cn.itcast.javaee.mybatis.app12.Student" id="studentMap">
- <id property="id" column="students_id"/>
- <result property="name" column="students_name"/>
- <result property="sal" column="students_sal"/>
- </resultMap>
- <!-- set 标签自动判断哪个是最后一个字段, 会自动去掉最后一个, 号 -->
- <update id="dynaUpdate" parameterType="map">
- update students
- <set>
- <if test="pname!=null">
- students_name = #{pname},
- </if>
- <if test="psal!=null">
- students_sal = #{psal},
- </if>
- </set>
- where students_id = #{pid}
- </update>
- </mapper>
来源: http://www.bubuko.com/infodetail-2573780.html