最近学习MyBatis，学习到注解方式实现增删改查使遇到异常，困惑的很长时间，最终找到解决问题的方法，共勉！
写好注解的接口后注册到配置文件时使用
方式一
?
问题来了，抛出异常如下：
org.apache.ibatis.exceptions.PersistenceException:
### Error building SqlSession.
### Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance. Cause: org.xml.sax.SAXParseException; lineNumber: 26; columnNumber: 66; 必须为元素类型 "mapper" 声明属性 "class"。
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:8)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:60)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:44)
at com.liuyunlong.mybatis.utils.MyBatisUtil.getSession(MyBatisUtil.java:22)
at com.liuyunlong.mybatis.test.Lesson3.add(Lesson3.java:20)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.eva luate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.eva luate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.apache.ibatis.builder.BuilderException: Error creating document instance. Cause: org.xml.sax.SAXParseException; lineNumber: 26; columnNumber: 66; 必须为元素类型 "mapper" 声明属性 "class"。
at org.apache.ibatis.parsing.XPathParser.createDocument(XPathParser.java:238)
at org.apache.ibatis.parsing.XPathParser.
(XPathParser.java:107)
at org.apache.ibatis.builder.xml.XMLConfigBuilder.
(XMLConfigBuilder.java:52) at org.apache.ibatis.session.SqlSessionFactor