第一种情形,传入单个参数 userId
service层:
@Override public User getUserInfo(Integer userId) {User user = userMapper.getUserInfo(userId);//省略 业务代码...return user; }
mapper层:
User getUserInfo(Integer userId);
mapper.xml:
<!--查询--> <select id="getUserInfo" resultType="com.demo.elegant.pojo.User">select userId from userswhere userId=#{userId}; </select>
第二种情况,传入多个参数 userId,sex 使用索引对应值
按照顺序传参
注意mapper层和xml层!
service层:
@Override public User getUserInfo(Integer userId,String sex) {User user = userMapper.getUserInfo(userId,sex);//省略 业务代码...return user; }
mapper层:
User getUserInfo(Integer userId,String sex);
mapper.xml:
<!--查询--> <select id="getUserInfo" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{0} and sex=#{1}; </select>
第三种情形,传入多个参数 userId,sex 使用注解@Param
service层
@Overrid public User getUserInfo(Integer userId,String sex) {User user = userMapper.getUserInfo(userId,sex);//省略 业务代码...return user; }
mapper层:
User getUserInfo(@Param("userId")Integer userId,@Param("sex")String sex);
mapper.xml:
<!--查询--> <select id="getUserInfo" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{userId} and sex=#{sex}; </select>
第四种情形,传入多个参数 使用User实体类传入
service层:
@Override public User getUserInfo(User user) {User userInfo = userMapper.getUserInfo(user);//省略 业务代码...return userInfo; }
mapper层:
User getUserInfo(User User);
mapper.xml:
<!--查询--> <select id="getUserInfo" parameterType="User" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{userId} and sex=#{sex}; </select>
第五种情形,传入多个参数, 使用Map类传入
service层:
@Override public User getUserInfo(Map map) {User user = userMapper.getUserInfo(map);//省略 业务代码...return user; }
mapper层:
User getUserInfo(Map map);
mapper.xml层:
<!--查询--> <select id="getUserInfo" parameterType="Map" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{userId} and sex=#{sex}; </select>
第六种情形,传入多个参,使用 map封装实体类传入
这种情况其实使用场景比较少,因为上面的各种姿势其实已经够用了
service层:
@Override public User getUserInfo1(Integer userId,String sex) {User userInfo = new User(userId,sex);Map<String,Object> map=new HashMap<String,Object>();map.put("user",userInfo);User userResult= userMapper.getUserInfo(map);//省略 业务代码...return userResult; }
mapper层:
User getUserInfo(Map map);
mapper.xml:
<!--查询--> <select id="getUserInfo" parameterType="Map" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{userInfo.userId} and sex=#{userInfo.sex}; </select>
第七种情形,即需要传入实体类,又需要传入多个单独参,使用注解@Param
service层:
@Override public User getUserInfo(User user,Integer age) {User userResult = userMapper.getUserInfo(user,age);//省略 业务代码...return userResult; }
mapper层:
User getUserInfo(@Param("userInfo") User user,@Param("age") Integer age);
mapper.xml:
<!--查询--> <select id="getUserInfo" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere userId=#{userInfo.userId} and sex=#{userInfo.sex} and age=#{age}; </select>
List传参
service层:
List<Integer>list= new ArrayList>();list. add(44);list. add(45);list. add(46); List<SysUser> sysUser= sysUserMapper. selectList(list);
mapper层:
List<SysUser> selectList(List<Integer> ids);
mapper.xml:
<select id="selectList"resultMap"BaseResultMap">select<include refid="Base_Column_List"/>from sys_userwhere id in<foreach item="item" index="index" collection="list"open="("separator","close=")"> #{item}</foreach></select>
数组传参
service层:
List<SysUser> sysuser= sysUserMapper. selectlist(new Integer[]{44,45,46});
mapper层:
List<SysUser> selectList(Integer[]ids);
mapper.xml:
<select id="selectList"resultMap"BaseResultMap">select<include refid="Base Column_List"/>from sys userwhere id in<foreach item="item" index="index collection="array"open="("separator="," close=")"> #{item}</foreach></select>
${}
使用这个的时候,只需要注意,如果是传递字段名或者表名,是直接做参数传入即可,
但是如果作为sql'语句里面使用的值, 记得需要手动拼接 ' ' 号。
例如, 传入单个参数 sex:
service层:
@Override public User getUserInfo(String sex) {sex="'"+sex+"'";User user = userMapper.getUserInfo(sex);//省略 业务代码...return user; }
mapper层:
User getUserInfo(String sex);
mapper.xml:
<!--查询--> <select id="getUserInfo" resultType="com.demo.elegant.pojo.User">select userIdfrom userswhere sex=${sex}; </select>
多个参数,那也就是使用注解@Param取名字解决即可。