struts2 提交数据到Action 老是报出异常： Inappropriate OGNL expression: null，请高手来，要具体原因。

Question

INFO - Unable to find 'struts.multipart.saveDir' property setting. Defaulting to javax.servlet.context.tempdir
WARN - Error setting value
ognl.InappropriateExpressionException: Inappropriate OGNL expression: null
at ognl.SimpleNode.setValueBody(SimpleNode.java:257)
at ognl.SimpleNode.evaluateSetValueBody(SimpleNode.java:177)
at ognl.SimpleNode.setValue(SimpleNode.java:246)
at ognl.Ognl.setValue(Ognl.java:476)
at com.opensymphony.xwork2.ognl.OgnlUtil.setValue(OgnlUtil.java:192)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:155)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:143)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.setParameters(ParametersInterceptor.java:273)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:187)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:148)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:93)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:306)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:128)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:104)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
这个是补充的整体异常。 解决好的附加。

Answer 1

从页面向后台Action传递参数
a.直接传值
在前台页面写<a href="user/user!add?name=a&age=8">
后台Action中必须有name和age的get,set方法
b.使用域模型传递参数
在前台页面写<a href="user/user!add?user.name=a&user.age=8">
在后台Action中有一个对象user的get和set方法。对象user所在的类有对应的name、age的get,set方法
c.ModelDriven
在前台页面写<a href="user/user!add?name=a&age=8">
后台放的是一个对象，和b不同的是类继承了一个接口implements ModelDriven<User>，其中User是对象user对应的类名
没有user的set和get方法，而是
@Override
public User getModel(){return user;}
这是我之前学习struts2时做的笔记。你看看能帮你解决问题不。