MyBatis3.2.3在单独测试使用时，遇到了一个依赖cglib的错误。

左手的ㄟ右手 2022-05-08 03:04 128阅读 0赞

org.apache.ibatis.exceptions.PersistenceException: 
    ### Error building SqlSession.
    ### The error may exist in SQL Mapper Configuration
    ### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.lang.IllegalStateException: Cannot enable lazy loading because CGLIB is not available. Add CGLIB to your classpath.
        at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:51)
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:35)
        at top.belmode.test.UserMapperTest.testGetUserById1(UserMapperTest.java:20)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
        at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
        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.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
        at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
        at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
    Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.lang.IllegalStateException: Cannot enable lazy loading because CGLIB is not available. Add CGLIB to your classpath.
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:106)
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:89)
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:49)
        ... 25 more
    Caused by: java.lang.IllegalStateException: Cannot enable lazy loading because CGLIB is not available. Add CGLIB to your classpath.
        at org.apache.ibatis.executor.loader.cglib.CglibProxyFactory.<init>(CglibProxyFactory.java:53)
        at org.apache.ibatis.session.Configuration.setLazyLoadingEnabled(Configuration.java:292)
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.settingsElement(XMLConfigBuilder.java:199)
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:100)
        ... 27 more
    Caused by: java.lang.ClassNotFoundException: Cannot find class: net.sf.cglib.proxy.Enhancer
        at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:188)
        at org.apache.ibatis.io.ClassLoaderWrapper.classForName(ClassLoaderWrapper.java:87)
        at org.apache.ibatis.io.Resources.classForName(Resources.java:254)
        at org.apache.ibatis.executor.loader.cglib.CglibProxyFactory.<init>(CglibProxyFactory.java:51)
        ... 30 more

这段主要是说 `Error parsing SQL Mapper Configuration. Cause: java.lang.IllegalStateException: Cannot enable lazy loading because CGLIB is not available. Add CGLIB to your classpath.`

但是呢，加入`cglib3.2.jar`，你会发现还是报这个错；百度得知，还需求asm包，然后导入`asm2.2.3.jar`，还是错的~  
因为 `mybatis3.2.3`无法引用`cglib3.2`只能引入`cglib2.2.x`，而`cglib2.3`不能使用`asm2.2.x`，需要更高的版本`asm3.x`。  
至此，问题解决，可以开启懒加载。

--------------------

> 问题来了，后面当`mybatis`更新到更高的`3.4.x`，发现不用依赖上述两个包了，喵喵？？

仔细看了一下，3.4.x与3.2.x包结构的区别：

![8263107-0600bc45711a8cce.png][]

mybatis3.4.5

![8263107-f1b7f78e64d35e8f.png][]

mybatis3.2.3

**应该是mybatis高版本已经整合了反射包，没看源码不知道是那种代理模式，是jdk代理，还是cglib代理，也不知道从哪个版本开始，但是，至少3.4.x是不需要添加cglib和asm的jar包的。**

[8263107-0600bc45711a8cce.png]: /images/20220508/79928fda003445918ab47ee318d3a7a0.png
[8263107-f1b7f78e64d35e8f.png]: /images/20220508/c8a8c20dd97a4363b0b5ccec6e67ae2a.png