在自定义 JSP 标记中传递 Java 对象值
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Passing a Java object value in Custom JSP tag
提问by Aditya R
I'm trying to pass a java variable from a custom jsp tag(Im using struts2 here to get the variable from the java class). Here is the error I'm getting.
我正在尝试从自定义 jsp 标记传递一个 java 变量（我在这里使用 struts2 从 java 类中获取变量）。这是我得到的错误。
javax.servlet.ServletException: /pages/editBidForm.jsp(51,8) According to TLD or attribute directive in tag file, attribute parentId does not accept any expressions
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:515)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)
....
Here is my jsp page(part)
这是我的jsp页面（部分）
<%@ taglib prefix="s" uri="/struts-tags" %>
<%@ taglib uri="/WEB-INF/taglib.tld" prefix="custom" %>
...
...
<table>
<tr>
<%
String bidformoid=null;
bidFormOid=request.getParameter("bidFormOid");
%>
<td> <custom:zorancustomtag parentType = "BIDFORM" parentId = "<%= pageContext.getAttribute("bidFormOid") %>" /></td>
</tr>
</table>
I'm not able to pass the parentId parameter correctly. I was able to pass the parentType parameter correctly since it involved only passing the string
我无法正确传递 parentId 参数。我能够正确传递 parentType 参数，因为它只涉及传递字符串
Here is the taglib file.
这是 taglib 文件。
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag
Library 1.2//EN"
"http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.1</jspversion>
<shortname>custom</shortname>
<tag>
<name>zorancustomtag</name>
<tagclass>com.zoran.action.CustomizedTag</tagclass>
<bodycontent>JSP</bodycontent>
<info>Tag having a body and attributes</info>
<attribute>
<name>name</name>
<required>false</required>
<rtexpvalue>false</rtexpvalue>
</attribute>
<attribute>
<name>parentType</name>
<required>true</required>
<rtexpvalue>true</rtexpvalue>
</attribute>
<attribute>
<name>parentId</name>
<required>true</required>
<rtexpvalue>false</rtexpvalue>
</attribute>
</tag>
</taglib>
And the java class of the custom tag.
以及自定义标签的java类。
public class CustomizedTag implements Tag {
private PageContext pageContext;
private Tag parent;
private String name;
private int parentId;
private String parentType;
List list = null;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
/* public CustomizedTag() {
super();
}
*/
public int doStartTag() throws JspException {
Session session = SessionUtil.getSession();
session.beginTransaction();
try {
JspWriter out = pageContext.getOut();
String parId = getParentId()+"";
// out.println(getParent()+" ");
String quer = "from ContentBase cb where cb.parentType=? AND cb.parentId=? ";//+parId;
Query query = session.createQuery(quer);
query.setParameter(0, getParentType());
query.setParameter(1, getParentId());
list = query.list();
ContentBase cb = new ContentBase();
if (null != list && !list.isEmpty()) {
cb = (ContentBase) list.get(0);
}
// pageContext.getOut().print("Sri "+getName());
out.println(cb.getDescription());
} catch (IOException ioe) {
throw new JspException("Error:"+ioe.getMessage());
}
return SKIP_BODY;
}
public int doEndTag() throws JspException {
return SKIP_PAGE;
}
public void release() {
}
public void setPageContext(PageContext pageContext) {
this.pageContext = pageContext;
}
public void setParent(Tag parent) {
this.parent = parent;
}
public Tag getParent() {
return parent;
}
public int getParentId() {
return parentId;
}
public void setParentId(int parentId) {
this.parentId = parentId;
}
public String getParentType() {
return parentType;
}
public void setParentType(String parentType) {
this.parentType = parentType;
}
}
Can anyone please let me know how to pass a java variable through custom jsp tag.
任何人都可以让我知道如何通过自定义 jsp 标记传递 java 变量。
Thanks, Aditya
谢谢，阿迪亚
回答by skaffman
The <rtexpvalue>element in your TLD should be <rtexprvalue>and needs to be set to true:
<rtexpvalue>您的 TLD 中的元素应该<rtexprvalue>并且需要设置为true：
<attribute>
<name>parentId</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
This allows runtime expressions to be supplied as the attribute value. I remain mystified as to who on the JSP design team thought it was a good idea to allow this to be set to false.
这允许将运行时表达式作为属性值提供。对于 JSP 设计团队中谁认为允许将其设置为 的好主意，我仍然感到困惑false。
回答by Gthompson83
Try wrapping the parentId value in ${}
尝试将 parentId 值包装在 ${} 中
<custom:zorancustomtag parentType = "BIDFORM" parentId = "${<%= pageContext.getAttribute("bidFormOid") %>}" />
