Parameter 'collection' not found

缺乏、安全感 2023-07-13 15:09 50阅读 0赞

`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>