mybatis--day01动态查询、动态更新、动态删除、动态插入

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动态查询

<?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.app11.Student" id="studentMap">        <id property="id" column="students_id"/>        <result property="name" column="students_name"/>        <result property="sal" column="students_sal"/>    </resultMap>    //传入的是map对象，会自动取map中相同名的值    <select id="findAll" parameterType="map" resultMap="studentMap">        select * from students        <where>            <if test="pid!=null">                and students_id = #{pid}            </if>            <if test="pname!=null">                and students_name = #{pname}            </if>            <if test="psal!=null">                and students_sal = #{psal}            </if>        </where>    </select></mapper>

//测试/** * 持久层  * @author AdminTC */public class StudentDao {    /**     * 有条件的查询所有学生     */    public List<Student> findAll(Integer id,String name,Double sal) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            Map<String,Object> map = new LinkedHashMap<String,Object>();            map.put("pid",id);            map.put("pname",name);            map.put("psal",sal);            return sqlSession.selectList("studentNamespace.findAll",map);        }catch(Exception e){            e.printStackTrace();            throw e;        }finally{            MybatisUtil.closeSqlSession();        }    }    public static void main(String[] args) throws Exception{        StudentDao dao = new StudentDao();        List<Student> studentList = dao.findAll(5,"哈哈",7000D);        for(Student s : studentList){            System.out.println(s.getId()+":"+s.getName()+":"+s.getSal());        }    }}

动态更新

<?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>

    /**     * 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=?    }

动态删除

<?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.app13.Student" id="studentMap">        <id property="id" column="students_id"/>        <result property="name" column="students_name"/>        <result property="sal" column="students_sal"/>    </resultMap>    <delete id="dynaDeleteArray">        delete from students where students_id in        <!-- foreach用于迭代数组元素             open表示开始符号             close表示结束符合             separator表示元素间的分隔符             item表示迭代的数组，属性值可以任意，但提倡与方法的数组名相同             #{ids}表示数组中的每个元素值         -->        <foreach collection="array" open="(" close=")" separator="," item="ids">            #{ids}        </foreach>    </delete>       <delete id="dynaDeleteList">        delete from students where students_id in        <foreach collection="list" open="(" close=")" separator="," item="ids">            #{ids}        </foreach>    </delete></mapper>

/** * 持久层  * @author AdminTC */public class StudentDao {    /**     * 根据ID批量删除学生(数组版本)     */    public void dynaDeleteArray(int... ids) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            sqlSession.delete("studentNamespace.dynaDeleteArray",ids);            sqlSession.commit();        }catch(Exception e){            e.printStackTrace();            sqlSession.rollback();            throw e;        }finally{            MybatisUtil.closeSqlSession();        }    }    /**     * 根据ID批量删除学生(集合版本)     */    public void dynaDeleteList(List<Integer> ids) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            sqlSession.delete("studentNamespace.dynaDeleteList",ids);            sqlSession.commit();        }catch(Exception e){            e.printStackTrace();            sqlSession.rollback();            throw e;        }finally{            MybatisUtil.closeSqlSession();        }    }    //测试    public static void main(String[] args) throws Exception{        StudentDao dao = new StudentDao();        //dao.dynaDeleteArray(new int[]{1,3,5,7,77});        //dao.dynaDeleteArray(1,3,5,7,77);        //dao.dynaDeleteArray(2,4,444);        List<Integer> ids = new ArrayList<Integer>();        ids.add(6);        ids.add(8);        ids.add(9);        dao.dynaDeleteList(ids);    }}

动态插入

<?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.app14.Student" id="studentMap">        <id property="id" column="students_id"/>        <result property="name" column="students_name"/>        <result property="sal" column="students_sal"/>    </resultMap>    <!-- sql片段对应字段名,id属性值任意 -->    <sql id="key">        <!-- 去掉最后一个, -->        <trim suffixOverrides=",">            <if test="id!=null">                students_id,            </if>            <if test="name!=null">                students_name,            </if>            <if test="sal!=null">                students_sal,            </if>        </trim>    </sql>    <!-- sql片段对应?,id属性值任意 -->    <sql id="value">        <!-- 去掉最后一个, -->        <trim suffixOverrides=",">            <if test="id!=null">                #{id},            </if>            <if test="name!=null">                #{name},            </if>            <if test="sal!=null">                #{sal},            </if>        </trim>    </sql>    <!-- <include refid="key"/>和<include refid="value"/>表示引用上面定义的sql片段 -->    <insert id="dynaInsert" parameterType="cn.itcast.javaee.mybatis.app14.Student">        insert into students(<include refid="key"/>) values(<include refid="value"/>)    </insert></mapper>

/** * 持久层  * @author AdminTC */public class StudentDao {    /**     * 插入学生     */    public void dynaInsert(Student student) throws Exception{        SqlSession sqlSession = null;        try{            sqlSession = MybatisUtil.getSqlSession();            sqlSession.insert("studentNamespace.dynaInsert",student);            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();        //dao.dynaInsert(new Student(1,"哈哈",7000D));//insert into 表名(*,*,*) values(?,?,?)        //dao.dynaInsert(new Student(2,"哈哈",null));//insert into 表名(*,*) values(?,?)        //dao.dynaInsert(new Student(3,null,7000D));//insert into 表名(*,*) values(?,?)        dao.dynaInsert(new Student(4,null,null));//insert into 表名(*) values(?)    }}

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