运行mybatis时报错：

lineNumber: 6; columnNumber: 40; 文档根元素 "mapper" 必须匹配 DOCTYPE 根 "configuration"。

Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 6; columnNumber: 40; 文档根元素 "mapper" 必须匹配 DOCTYPE 根 "configuration"。
	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:82)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:66)
	at com.sss.mybatis.test.MybatisTest.main(MybatisTest.java:19)
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 6; columnNumber: 40; 文档根元素 "mapper" 必须匹配 DOCTYPE 根 "configuration"。
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:109)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:92)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:80)
	... 2 more
Caused by: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 6; columnNumber: 40; 文档根元素 "mapper" 必须匹配 DOCTYPE 根 "configuration"。
	at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:256)
	at org.apache.ibatis.parsing.XPathParser.<init>(XPathParser.java:125)
	at org.apache.ibatis.builder.xml.XMLMapperBuilder.<init>(XMLMapperBuilder.java:78)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java:321)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:107)
	... 4 more
Caused by: org.xml.sax.SAXParseException; lineNumber: 6; columnNumber: 40; 文档根元素 "mapper" 必须匹配 DOCTYPE 根 "configuration"。
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
	at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
	

问题原因分析：想着在官网复制没毛病呀，仔细查看才发现自己复制错了，mapper与configuration大意大意了。

                      两个dtd是不一样的。