之前一直用的jfinal老版本3.5，一直很稳定，看到4.2发布了，于是决定与时俱进升级一下。但是，问题来了，启动很正常，但是涉及到service调用的基本都报错。注：4.2在本机windows下调试的时候也正常，但是部署到linux服务器上之后出问题了。
Caused by:
java.lang.ClassNotFoundException: com.work.web.system.daolian.DaoLianService$$EnhancerByJFinal
at java.lang.ClassLoader.findClass(ClassLoader.java:530)
at com.jfinal.proxy.ProxyClassLoader.findClass(ProxyClassLoader.java:64)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at com.jfinal.proxy.ProxyClassLoader.loadProxyClass(ProxyClassLoader.java:49)
at com.jfinal.proxy.ProxyFactory.getProxyClass(ProxyFactory.java:70)
at com.jfinal.proxy.ProxyFactory.get(ProxyFactory.java:41)
at com.jfinal.proxy.Proxy.get(Proxy.java:32)
at com.jfinal.aop.Duang.duang(Duang.java:42)
at com.work.web.system.daolian.DaoLianService.<clinit>(DaoLianService.java:16)
at com.work.web.system.daolian.DaoLianController.<init>(DaoLianController.java:20)
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 java.lang.Class.newInstance(Class.java:442)
at com.jfinal.core.ControllerFactory.getController(ControllerFactory.java:25)
at com.jfinal.core.ActionHandler.handle(ActionHandler.java:76)
at com.core.handler.XssHandler.handle(XssHandler.java:31)
at com.jfinal.core.JFinalFilter.doFilter(JFinalFilter.java:89)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
at com.core.filter.LoginFilter.chainAdmin(LoginFilter.java:115)
at com.core.filter.LoginFilter.doFilter(LoginFilter.java:48)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
at com.core.filter.WebFilter.doFilter(WebFilter.java:86)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
at com.core.filter.DomainFilter.doFilter(DomainFilter.java:50)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1602)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:502)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ssl.SslConnection$DecryptedEndPoint.onFillable(SslConnection.java:411)
at org.eclipse.jetty.io.ssl.SslConnection.onFillable(SslConnection.java:305)
at org.eclipse.jetty.io.ssl.SslConnection$2.succeeded(SslConnection.java:159)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
at java.lang.Thread.run(Thread.java:748)
Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error
SEVERE: /SessionService$$EnhancerByJFinal.java:3: error: package com.jfinal.aop does not exist
import com.jfinal.aop.Invocation;
^
Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error
SEVERE: /SessionService$$EnhancerByJFinal.java:4: error: cannot find symbol
public class SessionService$$EnhancerByJFinal extends SessionService {
^
symbol: class SessionService
Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error
SEVERE: /SessionService$$EnhancerByJFinal.java:6: error: package com.core.tools does not exist
public void del(com.core.tools.PageData p0) throws java.lang.Exception {
^
Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error
SEVERE: /SessionService$$EnhancerByJFinal.java:7: error: cannot find symbol
Invocation inv = new Invocation(this, 13L,
^
symbol: class Invocation
location: class com.work.web.system.session.SessionService$$EnhancerByJFinal
Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error
SEVERE: /SessionService$$EnhancerByJFinal.java:7: error: cannot find symbol
Invocation inv = new Invocation(this, 13L,
^
symbol: class Invocation
location: class com.work.web.system.session.SessionService$$EnhancerByJFinal总结一下，以上核心的报错如下：
Caused by: java.lang.ClassNotFoundException: com.work.web.system.daolian.DaoLianService$$EnhancerByJFinal Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error SEVERE: /SessionService$$EnhancerByJFinal.java:3: error: package com.jfinal.aop does not exist Jun 07, 2019 8:34:23 PM com.jfinal.proxy.ProxyCompiler error SEVERE: /SessionService$$EnhancerByJFinal.java:7: error: cannot find symbol Invocation inv = new Invocation(this, 13L,
在社区看到一篇帖子，跟我的情况很像，但是帖子并没有给出解决方案。http://www.jfinal.com/feedback/5931
目前我还在排查原因，尚未解决。已经暂时降到3.5版本了，降级后一切恢复正常。
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后续补充：
1.如果是web项目，jfinal最新版本已经解决上述问题
2.如果是非web项目，手动指定cglib为代理库可解决问题：ProxyManager.me().setProxyFactory(new CglibProxyFactory()); 更多请参考在线文档：https://jfinal.com/doc/4-8
再检查 JDK 最低要是 1.8 版本
最后，环境变量 CLASSPATH 最重要，检查配的环境变量，CLASSPATH 配置要是下面这样：
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
如果是 windows 系统，检查环境变量 CLASSPATH 的值为：
%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar
记得搞定后回来分享
升级到 4.2 功能、性能各方面要好很多