Mybatis框架中，Mapper文件参数获取一般有以下几种：
1、参数个数为1个（string或者int）
dao层方法为以下两种：
/**
* 单个int型
*/
public List<UserComment> findByDepartmentId(int dapartmentId);
/**
* 单个string型
*/
public Source findByTitle(String title);
对应的Mapper取值：
取值时应当注意，参数名字应该与dao层传入的参数名字相同。
/*单个int型*/
<select id="findByDepartmentId" resultType="com.bonc.wechat.entity.publicserver.UserComment">
select * from wx_user_comment where
department_id=#{departmentId}
order by createtime desc;
</select>
/*单个string型*/
<select id="findByTitle" parameterType="java.lang.String" resultType="com.bonc.wechat.entity.publicserver.Source">
select * from wx_source where
title=#{title};
</select>
或者直接使用通用方法获取参数
<select id="findByDepartmentId" resultType="com.bonc.wechat.entity.publicserver.UserComment">
select * from wx_user_comment where
department_id=#{_parameter}
order by createtime desc;
</select>
<select id="findByTitle" parameterType="java.lang.String" resultType="com.bonc.wechat.entity.publicserver.Source">
select * from wx_source where
title=#{_parameter};
</select>
2、参数个数为多个。
dao层方法：
/*****1.注解传参*****/
public List<UserTab> selectUserListExceptUserId
(@Param("USER_ID")String USER_ID,
@Param("LIMIT_POS")int LIMIT_POS,
@Param("LIMIT_SIZE")int LIMIT_SIZE);
对应的Mapper取值：
取值时应当注意，参数名字应该与dao层传入的参数名字(@param处声明的参数名)相同。
/****注解传参方式参数获取****/
<select id="selectUserListExceptUserId"
resultMap="userResMap">
select * from MH_USER
where USER_ID!=#{USER_ID}
and USER_STATE>9
order by NICK_NAME
limit #{LIMIT_POS},#{LIMIT_SIZE}
</select>
3、参数为map的形式(常用)
mapper中使用map的key取值
dao中的方法:
/*****1.参数为map*****/
public List<Source> search(Map<String,Object> param);
/***2.map的内部封装***/
Map<String,Object> param=new HashMap<String,Object>();
param.put("page", (page-1)*pageSize);
param.put("pageSize",pageSize);
param.put("keyword","%"+keyword+"%");
param.put("type",type);
List<Source> sources=sourceDao.search(param);
对应的Mapper取值：
<select id="search"
parameterType="java.util.Map"
resultType="com.bonc.wechat.entity.publicserver.Source">
select * from wx_source
where
<if test="keyword != null and keyword != ''">
(title like #{keyword(按map键取值)} or content like #{keyword}) and
</if>
type=#{type}
order by ordernum asc
limit #{page},#{pageSize};
</select>4、参数为对象(常用)
1.mapper中使用对象中的属性直接取值，在映射接口中的方法不加@Param
2.【对象.属性】取值：对象的名称一定要在映射接口中的方法中声明@Param并一致
dao中的方法:
/*****使用对象传参*****/
public int addUserComment(UserComment UC);
/*****对象中的属性*****/
private int id;
private int department_id;
private String telphone;
private String content;
private String createtime; 对应的Mapper取值：
<insert id="addUserComment"
parameterType="com.bonc.wechat.entity.publicserver.UserComment">
insert into wx_user_comment
(department_id,
telphone,
content,
createtime)
values(#{department_id},
#{telphone},
#{content},
#{createtime});
</insert>
*使用【对象.属性】取值。
dao层：
/******此示例中直接省去dao层，service直接绑定mapper层******/
public PageResult findPanoramaPage(Page page) throws Exception{
List<PageData> panoramaList = new ArrayList<PageData>();
try {
panoramaList = (List<PageData>)dao.findForList("PanoramaMapper.findPagePanorama", page);
} catch (Exception e) {
e.printStackTrace();
}
PageResult pageResult = new PageResult(page.getTotalResult(),panoramaList);
return pageResult;
}
对应的Mapper取值：
<select id="findPagePanorama"
parameterType="page"
resultType="pd">
SELECT
a.id as id,
a.project_code as projectCode,
a.project_name as projectName,
a.project_addr as projectAddr,
a.project_type as projectType
FROM
calm_project a
WHERE
a.is_valid=1
<if test="page.projectType != null and page.projectType != ''">
AND a.project_type = #{page.projectType}
</if>
<if test="page.keyword != null and page.keyword != ''">
AND (a.project_name LIKE '%${page.keyword}%' OR a.project_code LIKE '%${page.keyword}%')
</if>
ORDER BY
a.sort
</select>推荐使用第三和第四种，将所传的数据在controller层或者service层封装起来，传入mapper文件中取值。