mybaits 动态SQL语句

-------------------------动态查询---------------------------------------
<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>

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();
}
}
-----------------------------------动态更新-----------------------------------------
<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>

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();
}
}
-----------------------------------动态删除----------------------------------------------
<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>

/**
* 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();
}
}
------------------------------------动态插入----------------------------------------------
<!-- 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>

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();
}
}