高手们帮忙给看看是什么问题

[JavaPool]

<html:form action="admin_message.do" method="GET">
<html:text property="adminmessage.admin_name" />
</html:form>
页面和配置没问题我就不贴了
我的这个表单运行后报
javax.servlet.ServletException: No getter method for property adminmessage.admin_name of bean org.apache.struts.taglib.html.BEAN
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:673)
org.apache.jsp.index_jsp._jspService(index_jsp.java:82)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

错误。
我是按照书上的例子写的
我的值对象类和FORM类都是按照例子写的请问这个错误怎样改？

值对象类是

public class admin_message
{

public String admin_name;

public void setAdmin_Name(String name)
{
this.admin_name=name;
}

public String getAdmin_Name()
{
return this.admin_name;
}
}

FORM是
public class Admin_messageForm extends ActionForm {
private admin_message adminmessage=new admin_message();
public void setAdmin_Name(String name)
{
this.adminmessage.setAdmin_Name(name);
}
public String getAdmin_Name()
{
return this.adminmessage.getAdmin_Name();
}
public void setAdmin_message(admin_message adminmessage)
{
this.adminmessage=adminmessage;
}
public admin_message getAdmin_message(){
return this.adminmessage;
}
各位大侠们帮帮我吧！

[skycncomp]

No getter method for property adminmessage.admin_name of bean org.apache.struts.taglib.html.BEAN

[JavaPool]

怎样解决呢？我在值对象和FORM里都写了相应的方法了我也贴出来了