Mybatis配置文件报错：Error parsing SQL Mapper Configuration. ... Cannot find class 已找到解决方案

报错描述：

[DEBUG] 12:01:26.005 [main] o.a.i.l.LogFactory - Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter. 
[DEBUG] 12:01:26.027 [main] o.a.i.d.p.PooledDataSource - PooledDataSource forcefully closed/removed all connections. 
[DEBUG] 12:01:26.028 [main] o.a.i.d.p.PooledDataSource - PooledDataSource forcefully closed/removed all connections. 
[DEBUG] 12:01:26.028 [main] o.a.i.d.p.PooledDataSource - PooledDataSource forcefully closed/removed all connections. 
[DEBUG] 12:01:26.028 [main] o.a.i.d.p.PooledDataSource - PooledDataSource forcefully closed/removed all connections. 
Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException: 
### Error building SqlSession.
### The error may exist in userMapper.xml
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'userMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'User'.  Cause: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:82)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:66)
	at org.example.MyBatisDemo.main(MyBatisDemo.java:17)
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'userMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'User'.  Cause: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:133)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:110)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:80)
	... 2 more
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'userMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'User'.  Cause: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:125)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.parse(XMLMapperBuilder.java:98)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.mappersElement(XMLConfigBuilder.java:405)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:131)
	... 4 more
Caused by: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'User'.  Cause: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.builder.BaseBuilder.resolveClass(BaseBuilder.java:103)
	at org.apache.ibatis.builder.xml.XMLStatementBuilder.parseStatementNode(XMLStatementBuilder.java:105)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.buildStatementFromContext(XMLMapperBuilder.java:141)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.buildStatementFromContext(XMLMapperBuilder.java:133)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:123)
	... 7 more
Caused by: org.apache.ibatis.type.TypeException: Could not resolve type alias 'User'.  Cause: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:128)
	at org.apache.ibatis.builder.BaseBuilder.resolveAlias(BaseBuilder.java:132)
	at org.apache.ibatis.builder.BaseBuilder.resolveClass(BaseBuilder.java:101)
	... 11 more
Caused by: java.lang.ClassNotFoundException: Cannot find class: User
	at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:226)
	at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:103)
	at org.apache.ibatis.io.Resources.classForName(Resources.java:322)
	at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:124)
	... 13 more

 问题勘察：还有就是看自己的配置文件resultType这个位置是否标红

如果标红，表示配置文件无法对应包中的类 解决方案，使用全类名：

 附上配置文件代码：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="test">
<!--    Wrong-->
<!--    <select id="select" resultType="User">-->
<!--    Correct-->
    <select id="select" resultType="org.example.pojo.User">
        select * from tb_user;
    </select>
</mapper>