1. 如果傳入的是單引數且引數型別是一個List的時候，collection屬性值為list
2. 如果傳入的是單引數且引數型別是一個array陣列的時候，collection的屬性值為array
3. 如果傳入的引數是多個的時候，我們就需要把它們封裝成一個Map了，當然單引數也可以封裝成map，實際上如果你在傳入引數的時候，在MyBatis裡面也是會把它封裝成一個Map的，map的key就是引數名，所以這個時候collection屬性值就是傳入的List或array物件在自己封裝的map裡面的key

1.單引數List的型別：  <select id="dynamicForeachTest" resultType="Blog">   select * from t_blog where id in   <foreach collection="list" index="index" item="item" open="(" separator="," close=")">    #{item}   </foreach>  </select> public List<Blog> dynamicForeachTest(List<Integer> ids);  @Test  public void dynamicForeachTest() {   SqlSession session = Util.getSqlSessionFactory().openSession();   BlogMapper blogMapper = session.getMapper(BlogMapper.class);   List<Integer> ids = new ArrayList<Integer>();   ids.add(1);   ids.add(3);   ids.add(6);   List<Blog> blogs = blogMapper.dynamicForeachTest(ids);   for (Blog blog : blogs)    System.out.println(blog);   session.close();  } 2.單引數array陣列的型別：  <select id="dynamicForeach2Test" resultType="Blog">   select * from t_blog where id in   <foreach collection="array" index="index" item="item" open="(" separator="," close=")">    #{item}   </foreach>  </select> public List<Blog> dynamicForeach2Test(int[] ids);  @Test  public void dynamicForeach2Test() {   SqlSession session = Util.getSqlSessionFactory().openSession();   BlogMapper blogMapper = session.getMapper(BlogMapper.class);   int[] ids = new int[] {1,3,6,9};   List<Blog> blogs = blogMapper.dynamicForeach2Test(ids);   for (Blog blog : blogs)    System.out.println(blog);   session.close();  } 3 自己把引數封裝成Map的型別  <select id="dynamicForeach3Test" resultType="Blog">   select * from t_blog where title like "%"#{title}"%" and id in   <foreach collection="ids" index="index" item="item" open="(" separator="," close=")">    #{item}   </foreach>  </select> public List<Blog> dynamicForeach3Test(Map<String, Object> params);  @Test  public void dynamicForeach3Test() {   SqlSession session = Util.getSqlSessionFactory().openSession();   BlogMapper blogMapper = session.getMapper(BlogMapper.class);   final List<Integer> ids = new ArrayList<Integer>();   ids.add(1);   ids.add(2);   ids.add(3);   ids.add(6);   ids.add(7);   ids.add(9);   Map<String, Object> params = new HashMap<String, Object>();   params.put("ids", ids);   params.put("title", "中國");   List<Blog> blogs = blogMapper.dynamicForeach3Test(params);   for (Blog blog : blogs)    System.out.println(blog);   session.close();  } 專案中的例子：  <insert id="insertBatchBusiness_people" parameterType="map">             insert into tbl_business_people_#{businessId} (business_id,uid)             values             <foreach collection="list" item="item" index="index" separator=",">             (             #{item.business_id,jdbcType=VARCHAR},             #{item.uid,jdbcType=VARCHAR}             )         </foreach>       ON DUPLICATE KEY UPDATE updatetime=NOW()  </insert> dao 層:  public Integer insertBatchBusiness_people(@Param("businessId") Integer businessId,    @Param("list") List<Business_peopleEntity> list); sevice interface 層 public Integer insertBatchBusiness_people(List<Business_peopleEntity> item); sevice impl  層  @Override  public Integer insertBatchBusiness_people(    List<Business_peopleEntity> item) {   return business_peopleDao.insertBatchBusiness_people(item.get(0).getBusiness_id(),item);  }    <insert id="insertBatchSelect" parameterType="java.util.List">       insert into tbl_outcalldetail (outcalltaskid, user_id,   telephoneNo, typeno1,       price_range1, typeno2, price_range2,       typeno3, price_range3, kw,       url, recommend, state,       isaccept, remark, outcalluserid,       outcallusername, outcalltime) values     <foreach collection="list" item="item" index="index" separator=",">    (       #{item.outcalltaskid,jdbcType=INTEGER}, #{item.userId,jdbcType=VARCHAR},       #{item.telephoneno,jdbcType=VARCHAR}, #{item.typeno1,jdbcType=VARCHAR},       #{item.priceRange1,jdbcType=VARCHAR}, #{item.typeno2,jdbcType=VARCHAR},       #{item.priceRange2,jdbcType=VARCHAR}, #{item.typeno3,jdbcType=VARCHAR},       #{item.priceRange3,jdbcType=VARCHAR}, #{item.kw,jdbcType=VARCHAR},       #{item.url,jdbcType=VARCHAR}, #{item.recommend,jdbcType=VARCHAR}, #{item.state,jdbcType=INTEGER},       #{item.isaccept,jdbcType=INTEGER}, #{item.remark,jdbcType=VARCHAR}, #{item.outcalluserid,jdbcType=INTEGER},       #{item.outcallusername,jdbcType=VARCHAR}, #{item.outcalltime,jdbcType=TIMESTAMP}    )       </foreach>     </insert> <update id="updateBatchByPrimaryKeySelective" parameterType="java.util.List"> <foreach collection="list" item="item" index="index" open="" close="" separator=";">   update tbl_outcalldetail     <set >       <if test="item.state != null" >         state = #{item.state,jdbcType=INTEGER},       </if>       <if test="item.isaccept != null" >         isaccept = #{item.isaccept,jdbcType=INTEGER},       </if>       <if test="item.remark != null" >         remark = #{item.remark,jdbcType=VARCHAR},       </if>       <if test="item.outcalluserid != null" >         outcalluserid = #{item.outcalluserid,jdbcType=INTEGER},       </if>       <if test="item.outcallusername != null" >         outcallusername = #{item.outcallusername,jdbcType=VARCHAR},       </if>       <if test="item.outcalltime != null" >         outcalltime = #{item.outcalltime,jdbcType=TIMESTAMP},       </if>     </set>     where 1=1     <if test="item.outcalldetailid !=null" >     and id = #{item.outcalldetailid,jdbcType=INTEGER}     </if>     <if test="item.outcalltaskid !=null" >     and outcalltaskid = #{item.outcalltaskid,jdbcType=INTEGER}     </if>     <if test="item.userId !=null" >     and user_id = #{item.userId,jdbcType=VARCHAR}     </if> </foreach> </update>