<s:select>标签传值出错~~求指导。

Question

额，刚开始学SSH~~

[color=darkred]源码：[/color]

………… ………… …………

大类： 小类：

[color=darkred]bigCateList是通过BookDao类中的方法获取的，代码如下：[/color]
public List getBigCate() {

    try {
        Session session = MySessionFactory.currentSession();
        MySessionFactory.beginTransaction();
        List results = session.createQuery("from Bigcate").list();
        MySessionFactory.commitTransaction();
        MySessionFactory.closeSession();
        if (results != null && results.size() > 0) {
            return results;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

[color=darkred]表单提交的Action addBook方法的代码 如下 [/color]
public String addBook(){
Book book = new Book();
BookDao bookDao = new BookDaoImpl();
try{
book.setName(new String(bookname.getBytes("ISO-8859-1"),"GBK"));
book.setISBN(new String(ISBN.getBytes("ISO-8859-1"),"GBK"));
book.setAuthor(new String(author.getBytes("ISO-8859-1"),"GBK"));
book.setPress(new String(press.getBytes("ISO-8859-1"),"GBK"));
book.setPrice(price);
book.setSpecial(special);
book.setSalePrice(salePrice);
book.setInfor(new String(infor.getBytes("ISO-8859-1"),"GBK"));
book.setBigCateId(new String(bigCateId.getBytes("ISO-8859-1"),"GBK"));
book.setSmallCateId(new String(smallCateId.getBytes("ISO-8859-1"),"GBK"));
bookDao.addBook(book);
}catch (Exception ex) {
System.out.println("在执行BookMgrAction类中的addBook方法时出错：\n");
ex.printStackTrace();
}
return SUCCESS;
}

[color=darkred]表单提交后出错：[/color]
严重: Servlet.service() for servlet jsp threw exception
tag 'select', field 'list', name 'bigCateId': The requested list key 'bigCateList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]

Answer 1

你提交后是不是又返回到了一个页面，此页面上有你用的List.
而此list是没有值的。
你应该在取一次List ,这样返回到有list的页面才不会报错了。