jFinal中报对应模型不存在的错误(The Table mapping of model: demo.User not exists)

jFinal中报对应模型不存在的错误(The Table mapping of model: demo.User not exists)

贴出错误:

java.lang.RuntimeException: The Table mapping of model: demo.User not exists. Please add mapping to ActiveRecordPlugin: activeRecordPlugin.addMapping(tableName, YourModel.class).
	at com.jfinal.plugin.activerecord.TableMapping.getTable(TableMapping.java:45)
	at com.jfinal.core.ModelInjector.injectActiveRecordModel(ModelInjector.java:83)
	at com.jfinal.core.ModelInjector.inject(ModelInjector.java:50)
	at com.jfinal.core.ModelInjector.inject(ModelInjector.java:37)
	at com.jfinal.core.Controller.getModel(Controller.java:625)
	at demo.UserController.add(UserController.java:35)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at com.jfinal.core.ActionInvocation.invoke(ActionInvocation.java:55)
	at com.jfinal.core.ActionHandler.handle(ActionHandler.java:73)
	at com.jfinal.core.JFinalFilter.doFilter(JFinalFilter.java:72)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Thread.java:744)

解决思路:
百度了一下,这样的错误不是太多,可能是很少人用的原因吧。
1、首先，我修改了数据库连接方式，

C3p0Plugin cp = new C3p0Plugin("jdbc:mysql://localhost:3306/jfinal","root", "a");
me.add(cp);
ActiveRecordPlugin arp = new ActiveRecordPlugin(cp);
arp.addMapping("user", User.class);

但是还报这个错，我想可能是连接数据库的url什么的错了，于是，写了一个简单的demo，测试了一下数据库连接方式没有错。
2、有说自己写一个bean的，我想都没想，pass了，jFinal就是不需要自己写bean的。
3、后来仔细找代码的错误，发现了，没有加这行 

   me.add(cp);

于是加上，想这回应该可以了吧，可还是报错。

C3p0Plugin cp = new C3p0Plugin("jdbc:mysql://localhost:3306/jfinal","root", "a");
me.add(cp);
ActiveRecordPlugin arp = new ActiveRecordPlugin(cp);
me.add(arp);
arp.addMapping("user", User.class);

4、于是，我把需要传对象的页面的属性都稍作修改，加上user. 
这回就好了，一个小小的错误，百度了很久，都是粗心惹的祸。
下回注意。