xml配置问题--------不允许有匹配 "[xX][mM][lL]" 的处理指令目标

• 剪不断，理还乱，是BUG

•   相遇：不允许有匹配 "[xX][mM][lL]" 的处理指令目标

  在编写MyBatic框架时，纯手编写mybatic-config.xml文件，遇见了你

Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException:
### Error building SqlSession.
### Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 7; 不允许有匹配 "[xX][mM][lL]" 的处理指令目标。
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:80)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:64)
    at f.b.y.test.H.main(H.java:21)
Caused by: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 7; 不允许有匹配 "[xX][mM][lL]" 的处理指令目标。
    at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:259)
    at org.apache.ibatis.parsing.XPathParser.<init>(XPathParser.java:125)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.<init>(XMLConfigBuilder.java:82)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:77)
    ... 2 more
Caused by: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 7; 不允许有匹配 "[xX][mM][lL]" 的处理指令目标。
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:441)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368)
    at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1436)
    at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPIData(XMLScanner.java:723)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanPIData(XMLDocumentFragmentScannerImpl.java:1018)
    at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPI(XMLScanner.java:691)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:912)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:347)
    at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:257)
    ... 5 more

• 眼里寻它千百次，蓦然回首它却在开头处

• 相知：XML文件的第一个元素且前面不能空格

 <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
 
    <!-- configuration构建MyBatic上下文 -->
<configuration>
 
    <typeAliases>
    <typeAlias alias="user" type="f.b.y.pojo.User"/>
    </typeAliases> 
 
    <!--数据库环境  -->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.jdbc.Driver"/>
                    <property name="url" value="jdbc:mysql://localhost:3306/mybatisnote"/>
                    <property name="username" value="root"/>
                    <property name="password" value="12345678"/>
                </dataSource>
        </environment>
    </environments>
 
    <!-- 映射文件 -->
        <mappers>
            <mapper resource="f/b/y/pojo/sqlmap/usersql.xml"/>
        </mappers>
</configuration>

• 相爱：能不能再靠近一些（去掉前面空格）

 <?xml version="1.0" encoding="UTF-8" ?>

• 因为遇见，所以感悟

1、人总是不断的犯错误，面对错误，大多数人的开始选择是找错误，找方法解决它，往往事与愿违。对于错误本身而言，错误就是错误，无论大 小，都是致命的，细心显得十分重要。

2、每一个人都会犯错，可怕的不是错误本身，可怕的是没有勇气去面对、去发现、去解决它。

3、每一个人一路走来不可能一帆风顺，代码运行可能是你正常代码不正常或你不正常代码正常。那些错误将磨砺你的意志、丰富你的阅历，也 许，下次遇到它你会觉得错误是多么亲切可爱，解决错误是多么荣耀的一件事啊！