Parameter 'collection' not found

最新推荐文章于 2024-09-27 19:01:46 发布

原创最新推荐文章于 2024-09-27 19:01:46 发布 · 1.2k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#mybatis

mybatis 专栏收录该内容

20 篇文章

订阅专栏

在使用MyBatis进行数据库操作时，遇到Parameter 'collection'未找到的问题。错误源于dao层参数类型与sql中parameterType不匹配。案例1中，参数类型应从ArrayList改为Map。案例2提供了两种解决方案，一是调整dao层方法，二是修改sql语句中的parameterType。

nested exception is org.apache.ibatis.binding.BindingException: Parameter çollection'not found. Available parameters are [depId, userList, operator, param3, param1, param2]

工具：mybatis+pgsql

案例1

dao层

void insert(String depId, String operator, List<User> userList);

sql

<insert id = "insert" parameterType = "java.util.ArrayList">
	insert into user (username,sex,depId,create_by)
	     values
	   <foreach collection="collection" separator="," item="val">
	       (#{val.username}, #{val.sex}, #{depId}, #{create_by})
	   </foreach>
</insert>

执行后抛出异常信息：
"nested exception is org.apache.ibatis.binding.BindingException: Parameter 'collection' not found. Available parameters are [depId, userList, operator, param3, param1, param2]"
错误原因：parameterType = “java.util.ArrayList”，但是dao层参数类型是map，不匹配导致的。修改代码如下：
dao层: @Param

void insert(@Param("depId") String depId, 
            @Param("operator") String operator, 
            @Param("userList") List<User> userList);

sql: parameterType = "java.util.HashMap"

<insert id = "insert" parameterType = "java.util.HashMap">
	insert into user (username,sex,depId,create_by)
	     values
	   <foreach collection="collection" separator="," item="val">
	       (#{val.username}, #{val.sex}, #{depId}, #{create_by})
	   </foreach>
</insert>

案例2

dao层

List<User> select(List<User> userList);

sql

<select id = "select" parameterType = "java.util.ArrayList" returnType = "com.dto.User">
	select  * 
	  from  user 
	 where  id in
	   <foreach collection="userList" separator="," item="user" open="(" close=")">
	      #{user.username}
	   </foreach>
</select>

执行后抛出异常信息：
"nested exception is org.apache.ibatis.binding.BindingException: Parameter 'userList' not found. Available parameters are [collection, list]"

解决方案一：
dao层: @Param

void insert(@Param("userList") List<User> userList);

解决方案二：
sql: collection="collection" 或者 collection="list"

<select id = "select" parameterType = "java.util.ArrayList" returnType = "com.dto.User">
	select  * 
	  from  user 
	 where  id in
	   <foreach collection="collection" separator="," item="user" open="(" close=")">
	      #{user.username}
	   </foreach>
</select>