Struts中Action里对Form的运用理解

public ActionForward custDetail(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
String forward = "custDetail";
CustInforForm custInforForm = (CustInforForm) form;
try {
CustomerInfor customerInfor = custInforForm.getCustomerInfor();
if (!customerInfor.getCustomerId().equals("")) {
custInforForm.setCustomerInfor(customerInfor
.get(customerInfor.getCustomerId()));
custInforForm.setCheckboxSelect(customerInfor.getCustomerXxlx()
.split(","));//这句中customerInfor.getCustomerXxlx为空
}
} catch (ObjectPersistentException e) {
logger.error(e.getMessage(), e);
ActionErrors errors = new ActionErrors();
errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionError("error",
"查询失败:" + e.getMessage()));
saveErrors(request, errors);
}
return mapping.findForward(forward);
}

原因:CustomerInfor customerInfor = custInforForm.getCustomerInfor()会生成一个对象，并将对象地址赋给CustomerInfor类中private接口类型变量（假设为A），同时将A作为函数返回值赋给customerInfor，此时A和customerInfor同时指向这个对象。
custInforForm.setCustomerInfor(customerInfor.get(customerInfor.getCustomerId()));生成另一个对象，这个对象里各属性都有值，并将对象地址作为参数赋给Form里面的私有变量A，此时customerInfor仍然指向原来的对象,所以此时customerInfor里面没有CustomerXxlx的值

根据这个原理上面代码customerInfor.getCustomerXxlx()应该改为custInforForm.getCustomerInfor().getCustomerXxlx();才能正常运行。或者把有属性值的对象重新赋给customerInfor.如下代码：

代码

public ActionForward custDetail(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
String forward = "custDetail";
CustInforForm custInforForm = (CustInforForm) form;
try {
CustomerInfor customerInfor = custInforForm.getCustomerInfor();
if (!customerInfor.getCustomerId().equals("")) {
customerInfor = customerInfor.get(customerInfor.getCustomerId());
custInforForm.setCustomerInfor(customerInfor);
custInforForm.setCheckboxSelect(customerInfor.getCustomerXxlx().split(","));
}
// 在这里进行一条记录的查询操作！
} catch (ObjectPersistentException e) {
logger.error(e.getMessage(), e);
ActionErrors errors = new ActionErrors();
errors.add(ActionMessages.GLOBAL_MESSAGE, new ActionError("error",
"查询失败:" + e.getMessage()));
saveErrors(request, errors);
}
return mapping.findForward(forward);
}