Abnormal results and SPRINGMVC understanding when using MyBatis multi-table joint search

Today, when using MyBatis multi-table search, in the DOS window query can be out of the result set, but the use of MyBatis query when the last results returned only the last result

Then the study of the half-day did not get out, and later inadvertently found that the outermost layer from the table ID field after the results are detected, thus, the data is distinguished by the primary key, when the primary key is not in the query scope, the data default call the last statement

An instance of the service object cannot be used when using SPRINGMVC, and a null pointer exception is reported

Abnormal results and SPRINGMVC understanding when using MyBatis multi-table joint search