Struts logic:iterate input field - java

I currently have the following code and the data is displayed fine.
<logic:iterate name="myList" id="product" indexId="iteration" type="com.mycompany.MyBean">
<tr>
<td> <bean:write name="product" property="weight"/> </td>
<td> <bean:write name="product" property="sku"/> </td>
<td> <bean:write name="product" property="quantity"/> </td>
</tr>
</logic:iterate>
But now I need to make the "quantity" part modifiable. The user should be able to update that field, press submit and when its sent to the server, "myList" should automatically update with the new quantities.
I've tried searching for help on this but all I keep finding is examples on how to display data only, not modify it. Any help would be appreciated.


So this is tricky, because there are many things to get done in order for it to work. First, declare your tags inside the iterator with the html tags, with attribute INDEXED=TRUE and an ID DIFFERENT THAN THE NAME, i also took out the "indexId" attribute to use the simple "index" word for the index:
<logic:iterate name="myList" id="myListI" type="com.mycompany.MyBean">
<tr>
<td> <html:input name="myListI" property="weight" indexed="true"/> </td>
<td> <html:input name="myListI" property="sku" indexed="true"/> </td>
<td> <html:input name="myListI" property="quantity" indexed="true"/> </td>
</tr>
after that, in order for struts to be able to get and set the attributes of your beans, you need to declare EXTRA get and set methods inside your collection object, using the name you wrote in the id of the iterate tag. In this case, you would write 2 extra get and set methods for the "myListI" :
public void setMyListI(int index, myBean value){
this.myList.add(value);
}
public myBean getMyListI(int index){
return this.myList.get(index);
}


I think Th0rndikes answer is mostly correct. My implementation is slightly different, so it might be worth trying this as well.
Form
private List<Parameter> activeParameters;
public List<Parameter> getActiveParameters() {
return activeParameters;
}
public Parameter getParam(int index){
return this.activeParameters.get(index);
}
JSP
<logic:iterate name="MyForm" property="activeParameters" id="param">
<tr>
<td><bean:write name="param" property="prompt"/></td>
<td><html:text name="param" property="value" indexed="true"/></td>
</tr>
</logic:iterate>
In summary, I didn't use Type in the iterate tag, using the property tag instead. In the bean adding a getter with matched the name of the iterate ID in the JSP (param) with an index as a method parameter did the trick.


Take a look at this: http://wiki.apache.org/struts/StrutsCatalogLazyList
Indexed Properties
Struts html tags have an indexed attribute which will generate the
appropriate html to populate a collection of beans when the form is
submitted. The trick is to name the id attribute to the same as the
indexed property.
For example the following jsp...
<logic:iterate name="skillsForm" property="skills" id="skills">
<html:text name="skills" property="skillId" indexed="true"/>
</logic:iterate>
...will generate the following html
<input type="text" name="skills[0].skillId value="..."/>
<input type="text" name="skills[1].skillId value="..."/>
....
<input type="text" name="skills[n].skillId value="..."/>
When the form is submitted BeanUtils will first call the
getSkills(index) method to retrieve the indexed bean followed by
setSkillId(..) on the retrieved bean.


Theoretically, the indexed attribute of the struts html tags could be used for this:
Valid only inside of logic:iterate tag. If true then name of the html tag will be rendered as "id[34].propertyName". Number in brackets will be generated for every iteration and taken from ancestor logic:iterate tag.
But, there is no corresponding indexed attribute on the html:errors tag, which limits its usefulness. Also, the required combination of id, name and property attributes can be rather confusing.
I found it easier to use jsp scriptlets to generate the property name including the iteration index. The following code requires that your form has a string array property "quantity".
<% int idx=0; %>
<logic:iterate ...>
<html:text property='<%= "quantity[" + idx + "]" %>'/>
<html:errors property='<%= "quantity[" + idx + "]" %>'/>
<% i++; %>
</logic:iterate>

Related

Retrieve an array of parameters from a servlet [duplicate]

I am able to display an ArrayList of beans in a JSP form using JSTL by looping through the list and outputting the bean properties in a HTML input tag.
<c:forEach items="${listOfBeans}" var="bean">
<tr>
<td><input type="text" id="foo" value="${bean.foo}"/></td>
<td><input type="text" id="bar" value="${bean.bar}"/></td>
</tr>
</c:forEach>
How do I code the JSP so that when the page submits then the updated values are in the appropriate item of the the ArrayList?

Given this simplified model:
public class Item {
private Long id;
private String foo;
private String bar;
// ...
}
Here's how you can do it provided ${items} is List<Item>:
<c:forEach items="${items}" var="item">
<tr>
<td>
<input type="hidden" name="id" value="${item.id}" />
<input name="foo_${item.id}" value="${fn:escapeXml(item.foo)}" />
</td>
<td>
<input name="bar_${item.id}" value="${fn:escapeXml(item.bar)}" />
</td>
</tr>
</c:forEach>
(note the importance of fn:escapeXml() as XSS attack prevention)
So, basically, you need to set the item's unique identifier as a hidden input field in each row as shown in above snippet:
<input type="hidden" name="id" value="${item.id}" />
And you should in turn use this id as suffix of name of all input fields in the same row such as:
<input name="foo_${item.id}" ... />
In the servlet, you can collect all values of <input type="hidden" name="id" ...> from all rows by request.getParameterValues(). Just loop over it and then grab the individual inputs by id.
for (String id : request.getParameterValues("id")) {
String foo = request.getParameter("foo_" + id);
String bar = request.getParameter("bar_" + id);
// ...
}
You can also do this all without that id and grab all inputs by name as an array like so name="foo" and request.getParameterValues("foo"), but the ordering of request parameters is not under your control. HTML forms will send it in order, but the enduser can easily manipulate the order.
No need for JavaScript mess here.
See also:
Show JDBC ResultSet in HTML in JSP page using MVC and DAO pattern
ServletRequest.getParameterMap() returns Map<String, String[]> and ServletRequest.getParameter() returns String?
Send an Array with an HTTP Get

Displaying ${} of record from jsp to jsp

<c:forEach var = "student" items="${result}">
<tr>
<th>${student.name}</th>
<th>Notify</th>
</tr>
</c:forEach>
This is my output.jsp. Notice that I've put a link "Notify" to forward it on display.jsp. But I'm not sure how to display a record of student.name onto my display.jsp 's textbox. Thanks

You have to pass the student name over to the display.jsp (e.g. using a GET parameter).
Modify your link as follows:
<th>Notify</th>
Inside your display.jsp your textbox may look like this:
<input type="text" name="studentName" value="${param['studentName']}" />

How to handle buttons with same value but different names in Spring

I have a table that is dynamically created that has rows of movies.
It has a title column,
a media type column,
a rating column,
and a column that contains a "view" button.
When one of these view buttons is clicked,
I would like to go to a page that contains all the details of that movie by sending the title to the controller so I can query for it in mySql.
The problem is that for all these buttons,
the value is always going to be "view".
So my solution is to make the name of the button different as shown in the code below (this is the raw html generated from the jsp):
<html>
<body>
<form action="someAction">
<table>
<tr>
<th>title</th>
<th>type</th>
<th>rating</th>
</tr>
<tr>
<td>title1</td>
<td>DVD</td>
<td>R</td>
<td><input type="submit" name="mediaType.title1" value="view"></td>
</tr>
<tr>
<td>title2</td>
<td>DVD</td>
<td>R</td>
<td><input type="submit" name="mediaType.title2" value="view"></td>
</tr>
<tr>
<td>title3</td>
<td>BLU-RAY</td>
<td>PG-13</td>
<td><input type="submit" name="mediaType.title3" value="view"></td>
</tr>
</table>
</form>
</body>
</html>
I could then use a parameterMap to figure out which view was pressed.
That is messy and Spring has to have some way of being able to do this.
I thought something like this would work in the controller:
#RequestMapping("someAction", params = "mediaType.{title}=view")
public ModelAndView loadPage(String title) {
// use title to query mysql
// build Model
// return ModelAndView
}
However this doesn't work.
Is there something that I can use in Spring that would be simpler and cleaner like above instead of getting the parameterMap from the request?

If I'm understanding this correctly, you have rows of information organized into a table. You're looping through some kind of collection, which has the side effect of making each input field have similar 'name' attributes. As a result, it's difficult to determine which input fields you really care about. You've then chosen to use the button as an identifier (presumably, because only the one button you actually click on get's added to the request -all the others don't get submitted) to determine which 'row', and subsequent input fields.
I think this might all come down to which 'button' you're using. If you're using a literal input tag (type="submit" or "button") the 'value' attribute is what the user sees as the text on the button -so, you're forced to play shenanigans with the 'name' attribute (presumably by adding an index to the name, splitting the string once you get it out of the request, and using that identifier to get the other parameters out of the request that also have the same identifier appended to their 'name' attribute).
JSP
<input type="submit" name="view${varStatus.index}" value="View" />
HTML Source
<input type="submit" name="view3" value="View">
You should probably use the button tag instead. It allows the text that the user sees to be different than the value that is submitted in the request.
JSP
<button type="submit" name="view" value="${varStatus.index}" >View</button>
HTML Source
<button type="submit" name="view" value="3">View</button>
This gives you the 'identifier' for the row.
How Spring fits into this:
I played with the #RequestMapping and the #RequestParam annotations, and was unable to get Spring to give me the values directly into the controller. But, I was able to do it by writing a custom HandlerMethodArgumentResolver along with a custom annotation.
note: I'm using annotations and java config instead of xml config, AND probably more importantly -this was a quick and dirty example to get it working. adjust it as needed for your situation.
HandlerMethodArgumentResolver
Annotation
Controller method

Instead of putting the table inside one form, you could put multiple forms inside the table, in the TRs:
<tr>
<form action="someAction">
<td>title1<input type='hidden' name='title' value='title1' /></td>
<td>DVD</td>
<td>R</td>
<td><input type="submit" value="view"></td>
</form>
</tr>
Then each title has its own form and you send in the title (always with parameter name of title) from a hidden input.

The solution lies in this statement:
"I have a table that is dynamically created that has rows of movies".
Presumably,
you are looping through a list of movies and generating the table in the jsp file and each row has some unique identifier.
Add a hidden to identify the selected row.
Set the value of the hidden value in an onclick handler from the submit buttons.
Here is some example stuff:
<form ...>
<c:forEach blah var="row">
<tr>
...
<td><input type="submit" value="View" onclick="setSelectedRow('${row.id}')"/></td>
</c:forEach>
<input type="hidden" id="blammy" name="blammy" value=""/>
</form>
<script type="text/javascript">
function setSelectedRow(rowId)
{
... set blammy.value equal to rowId.
}
</script>
// the id is used by JavaScript to find the object in the DOM.
// the name is what appears in the request.
#RequestMapping("someAction")
public ModelAndView loadPage(
#RequestParameter("blammy") final String blammy)
{
...
}

Validate programatically generated form fields on client side and server side

I have a struts2 form that is programatically generated upon request. The element names for all the fields are the same namely idA and paramValue because I am passing the form values as array and looping through it for database inserts. Inserts are now OK, but I am still finding out how to validate the form.
Here's the form:
<s:iterator value="sysParamList" var="sysParam">
<tr>
<td>
<strong><s:property value="paramName" /></strong>
<input type="hidden" name="idA" value="<s:property value="id" />" />
</td>
<td>
<input type="text" name="paramValue" />
</td>
</tr>
</s:iterator>
The properties in my action are declared like
private String[] idA;
private String[] paramValue;
And I pass these in my DAO as-is. The DAO does the looping through the array for database insert.
I can validate forms using jquery.validate IF the form is hard coded in the JSP.

How to use a variable data as a scope variable in jstl

I want to dynamically create variable names in java el.
The problem is that the second line returns sessionScope.saved_activity as a string instead of data.
<c:set var="savedKey" value="sessionScope.saved_${entry.key}" />
<td> <input type="text" name="${entry.key}" value="${savedKey}"> </td>
How can I retrieve the data from a string in el ?

You need to create the sole key name and then use that as a dynamic key of the ${sessionScope} with the brace notation.
<c:set var="savedKeyName" value="saved_${entry.key}" />
<input type="text" name="${entry.key}" value="${sessionScope[savedKeyName]}">

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