Shulou(Shulou.com)06/03 Report--

This article is about what the parameterType input parameter types of MyBatis have. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

The parameter type passed in by parameterType of MyBatis

In the configuration of the mybatis mapping API, select,insert,update,delete and other elements all mention the use of parameterType. ParameterType is the input parameter. When configuring, you can configure the corresponding input parameter type. ParameterType has basic data types and complex data type configurations.

1. There are two types of input parameter parameterType for MyBatis.

1. 1. Basic data types: int, string, long, Date

1. 2. Complex data types: classes (JavaBean, Integer, etc.) and Map

two。 How to get the value in a parameter

2.1 basic data type: # {Parameter} get the value in the parameter

2.2 complex data types: # {attribute name}, while # {key} in map

3. Case

3.1 introduction of long type

Mapper API code:

Public User findUserById (Long id)

Xml Code:

Select * from user where id = # {id}

3.2 incoming List

Mapper API code:

Public List findUserListByIdList (List idList)

Xml Code:

Select * from user user user.ID in (# {id})

The most critical and error-prone thing when using foreach is the collection attribute.

This property must be specified, but the value of the property is different in different cases, mainly in the following three cases:

1. If a single parameter is passed and the parameter type is a List, the value of the collection attribute is list

two。 If a single parameter is passed and the parameter type is an array array, the property value of collection is array

3. If multiple parameters are passed in, we need to encapsulate them into a Map. Of course, a single parameter can also be used.

3.3 pass in an array:

Mapper API code:

Public List findUserListByIdList (int [] ids)

Xml Code:

Select * from user user user.ID in (# {id})

3.4 incoming map

Mapper API code:

Public boolean exists (Map map)

Xml Code:

SELECT COUNT (*) FROM USER user and user.CODE = # [code] and user.ID = # {id} and user.ID in ( # {id})

When there is a list or array in MAP, the collection in foreach must be the variable name of a specific list or array.

For example, here MAP contains a list named idList, so idList is used in MAP, which is different from passing list or array alone.

3.5 pass in JAVA object

Mapper API code:

Public int findUserList (User user)

Xml Code:

SELECT COUNT (*) FROM USER user and user.CODE = # [code] and user.ID = # {id} and user.ID in ( # {id})

When there is a list or array in the JAVA object, the collection in the foreach must be the variable name of the concrete list or array.

For example, here User contains a list named idList, so idList is used in User, which is different from passing list or array alone.

3.6 Note @ Param

Example 1:

Annotate a single attribute; this is similar to renaming the parameter once

Mapper API code:

List selectUserByTime (@ Param (value= "startdate") String startDate)

Xml Code:

Select * from t_user where create_time > = to_date (# {startdate,jdbcType=VARCHAR}, 'YYYY-MM-DD')

Example 2:

Note javaBean

Mapper API code:

List selectUserByTime (@ Param (value= "dateVO") DateVO dateVO)

Xml Code:

Select * from t_user where create_time > = to_date (# {dateVO.startDate,jdbcType=VARCHAR}, 'YYYY-MM-DD') and create_time < to_date (# {dateVO.endDate,jdbcType=VARCHAR}) 'YYYY-MM-DD') parameterType= "Long" select from member m where m.IS_DELETE of mybatis =' N' and m.member_id IN # {item JdbcType=DECIMAL} public ServiceMessage selectByPrimaryKeyByArrayMemberId (List memberIds) {try {if (memberIds = = null | | memberIds.size () = = 0) {return super.returnParamsError ("parameter is empty!") ;} List list = memberMapper .selectByPrimaryKeyArrayMemberId (memberIds); return super.returnCorrectResult (list);} catch (Throwable e) {return super.returnException (e);}} public ServiceMessage selectByPrimaryKeyByArrayMemberId (List memberIds); List selectByPrimaryKeyByArrayMemberId (List memberIds) @ Test public void testSelectByPrimaryKeyByArrayMemberId () {InternalMemberService internalMemberService = J1SOAHessianHelper.getService (url,InternalMemberService.class); List memberIds = new ArrayList (); memberIds.add (1l); memberIds.add (21); memberIds.add (1855l); ServiceMessage sm = internalMemberService.selectByPrimaryKeyByArrayMemberId (memberIds); System.out.println (sm.getResult ());} Thank you for reading! This is the end of this article on "what are the parameterType input parameter types of MyBatis?". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it out for more people to see!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.