Differences and application scenarios between resulttype and resultmap

Project scenario ：

Tips ： Here is a brief introduction to the background of the project ：
Very happy , This problem is solved by comparison , Or the original way to solve the problem ：
1. check 2 Than 3 Cumulative

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Problem description

Tips ： The problems encountered in the project are described here ：

One 、 See this problem , You may think that the entity class is not in mybatis-config.xml Configuring aliases in （alias） As a result of , As shown in the figure below ：

After comparison , I found myself resultMap It has been written. resultType

Cause analysis ：

Tips ： Fill in the analysis of the problem here ：
MyBatis In query select When mapping , Return type can be used resultType, It can also be used. resultMap,resultType Is a direct representation of the return type , and resultMap To the outside ResultMap References to , however resultType Follow resultMap Can't exist at the same time .
stay MyBatis Query mapping , In fact, every attribute found is put in a corresponding Map Inside , Where key is property name , Value is its corresponding value .
① When the return type property provided is resultType when ,MyBatis Will Map The key value pairs in it are assigned to resultType Property corresponding to the specified object . So actually MyBatis The return type of each query mapping of is ResultMap, Only when the return type property provided is resultType When ,MyBatis To assign a corresponding value to resultType Properties of the specified object .
And here is the capital corresponding map, Lowercase names correspond to map The number
② When the return type provided is resultMap when , because Map Can't represent domain model well , We need to further transform it into corresponding objects , This is often useful in complex queries .

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Solution ：

Tips ： Fill in the specific solution to the problem here ：

I fill in resulttype No problem. , There is something wrong with the assignment , however resultMap Applications that will be mapped .over. 2 Problems have been solved .