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This article mainly introduces the @ Autowired annotation injected xxxMapper error report how to do, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

@ Autowired comment injected xxxMapper error project scenario

Mybatis-Plus test

Problem description

In the test of the Mybatis-Plus scenario, it is found that the userMapper injected through the @ Autowired annotation will report an error.

This is because UserMapper is not a class that can create objects, but an interface.

@ Override public void run () {bytes = mmInStream.read (buffer); mHandler.obtainMessage (READ_DATA, bytes,-1, buffer). SendToTarget ();} solution

Option 1:

By adding @ Repository annotations.

Option 2:

Without using the @ Repository annotation, you can achieve injection by changing the @ Autowired annotation to the @ Resource annotation.

Analysis.

@ Autowired will report an error because the interface is not implemented

1. @ Autowired performs bean matching in byType mode by default, and @ Resource matches bean in byName mode by default.

2. @ Autowired is the annotation of Spring, and @ Resource is the annotation of J2EE. The package names of these two annotations are clear when you take a look at the import of annotations.

Spring belongs to a third party, and J2EE is Java's own thing, so it is recommended to use @ Resource annotations to reduce the coupling between code and Spring.

@ Autowired failed to load Mapper with an error of 404 or 500

When I have been misarranging, looking for annotations to add less or the database can not get the file, carelessness deceived me.

When @ Autowired fails to load Mapper and reports an error of 404or 500, you should pay more attention to the following points

Whether the package name is the same, and whether the package name is the same when loading the Mapper interface

Whether or not Autowired has been added to private XXXMapper xxxmapper;. If the startup class cannot start the display, it must be added (request = false)

The startup class must be placed under the java package, but under your com.xxxx package.

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