关于#MyBatis#的问题，如何解决？

MyBatis保错

org.apache.ibatis.exceptions.PersistenceException: 
### Error building SqlSession.
### The error may exist in mapper/BookMapper.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 'mapper/BookMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Book'.  Cause: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:52)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:36)
    at com.mywork.util.MyBatisUtils.<clinit>(MyBatisUtils.java:21)
    at Test.MyBatisTest.<init>(MyBatisTest.java:11)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:217)
    at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:266)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
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 'mapper/BookMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Book'.  Cause: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:121)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:98)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:50)
    ... 26 more
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'mapper/BookMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Book'.  Cause: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:122)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.parse(XMLMapperBuilder.java:94)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java:374)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:119)
    ... 28 more
Caused by: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Book'.  Cause: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.builder.BaseBuilder.resolveClass(BaseBuilder.java:118)
    at org.apache.ibatis.builder.xml.XMLStatementBuilder.parseStatementNode(XMLStatementBuilder.java:102)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.buildStatementFromContext(XMLMapperBuilder.java:137)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.buildStatementFromContext(XMLMapperBuilder.java:130)
    at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java:120)
    ... 31 more
Caused by: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Book'.  Cause: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:120)
    at org.apache.ibatis.builder.BaseBuilder.resolveAlias(BaseBuilder.java:149)
    at org.apache.ibatis.builder.BaseBuilder.resolveClass(BaseBuilder.java:116)
    ... 35 more
Caused by: java.lang.ClassNotFoundException: Cannot find class: Book
    at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:200)
    at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:89)
    at org.apache.ibatis.io.Resources.classForName(Resources.java:261)
    at org.apache.ibatis.type.TypeAliasRegistry.resolveAlias(TypeAliasRegistry.java:116)
    ... 37 more

java.lang.NullPointerException
    at com.mywork.util.MyBatisUtils.getSession(MyBatisUtils.java:29)
    at Test.MyBatisTest.<init>(MyBatisTest.java:11)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:217)
    at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:266)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)


Process finished with exit code -1

项目结构为：

BookMapper.xml 这个文件路径写错了

修改： xml的资源相对路径要和你的mapper接口的包目录相同

你的resources目录下的路径和java目录下的路径不一致，修改方法：
在resources目录下创建com\mywork\mapper目录，将BookMapper.xml和CustomerMapper.xml拷贝到这个目录中。

不知道你这个问题是否已经解决, 如果还没有解决的话:

帮你找了个相似的问题, 你可以看下: https://ask.csdn.net/questions/25285
你也可以参考下这篇文章：为什么要用MyBatis？MyBatis解决了什么问题？
除此之外, 这篇博客: MyBatis常见面试题汇总中的 MyBatis总如何执行批处理？ 部分也许能够解决你的问题, 你可以仔细阅读以下内容或者直接跳转源博客中阅读:
- 使用BatchExecutor完成批处理

如果你已经解决了该问题, 非常希望你能够分享一下解决方案, 写成博客, 将相关链接放在评论区, 以帮助更多的人 ^-^