Spring POST a large list of objects to controller - java

I followed the code from http://viralpatel.net/blogs/spring-mvc-multi-row-submit-java-list/ to post a list of objects to my Spring Controller. Soon, I ran into IndexOutOfBoundsException when the list size reached 256.
I found an answer which said setting the setAutoGrowCollectionLimit in WebDataBinder would solve this issue. So in my controller I did:
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.setAutoGrowCollectionLimit(2048);
}
#RequestMapping(value="/upload", method=RequestMethod.POST)
public String postData(Model model){
List<Products> products = //Some processing to get products list
ProductList productList = new ProductList();
productList.setProducts(products);
System.out.println(“Total records loaded: "+products.size());
model.addAttribute("productform", productList);
return “upload”;
}
#RequestMapping(value=“/process”, method=RequestMethod.POST)
public String uploadProcessedData(#ModelAttribute("productform") ProductList productList){
System.out.println(“Total records received: “+productList.getProducts().size());
return "upload";
}
My JSP code:
<form:form method="post" action="${pageContext.request.contextPath}/process” modelAttribute="productform">
<table>
<tr>
<th>Record</th>
<th>name</th>
</tr>
<c:forEach var="product" items="${productform.products}" varStatus="status">
<tr>
<td><c:out value="${status.index + 1}" /></td>
<td><input name="products[${status.index}].name” value="${product.name}”/></td>
</tr>
</c:forEach>
</table>
<input type="submit" value="Save" />
</form:form>
However, my form has 1000+ records and the controller only receives 556 records. Why this number? Is this because of any size limit? How can I get Spring to load all the 1000+ records.

You might want to add the enctype=multipart/form-data in the form tag for huge data, especially if you have non-ASCII characters in the payload. That might enable sending huge data in chunks.

Related

Output of a large table in Thymeleaf

The Spring-Boot App.
I want to output a table with data from the Book class to html.
Controller:
#GetMapping("/books")
public String showBooks(HttpServletRequest request, Model model) {
allBooks = bookService.getAll();
model.addAttribute("allBooks", allBooks);
return "books";
}
I use Thymeleaf.
Here is a snippet of html code:
<table border="1" style="width:250px">
<tr>
<th>No</th>
<th>Name</th>
</tr>
<tr th:each="allBooks, state : ${allBooks}">
<td th:utext="${state.count}">No</td>
<td th:text="${allBooks.name}">A Book'</td>
</tr>
</table>
There are more than 100 entries in the Book class.
How do I display them correctly so that they display 10 entries per page?
Thymeleaf is able to do this? Or do I need to use javaScript?

JSP Input value To Java Method -> HttpServletRequest gives NULL value

Hello Guys.
I have simple Storage page whichs display all Products from DB.
I set to each of them with Unique name to change the Amount of product.
When i want to catch this value in Java method its returns me null.
Can you help me what i need to do to corretly catching value's in this text inputs ?
Controller :
#Controller
public class StoragePageController extends HttpServlet {
#GET
#RequestMapping(value = "/storage/subamount/{id}")
public String substractTheAmountValue(#PathVariable("id") int id, Model model, HttpServletRequest request) {
String amount_req = request.getParameter("amount_sub_" + id);
System.out.println(amount_req);
return null;
}
}
JSP fragment :
<c:set var="licznik" value="${recordStartCounter }" />
<div align="center">
<table width="1000" border="0" cellpadding="6" cellspacing="2">
<c:forEach var="u" items="${productList }">
<c:set var="licznik" value="${licznik+1}" />
<tr onmouseover="changeTrBg(this)" onmouseout="defaultTrBg(this)">
<td align="right"><c:out value="${licznik }" /></td>
<td align="left"><c:out value="${u.description }" /></td>
<td align="left"><c:out value="${u.amount }" /></td>
<td align="center"><input type="text" name="amount_sub_${licznik}" id="amount_sub_${licznik}"></td>
<td align="center"><input type="button" value="Substract the value" onclick="window.location.href='${pageContext.request.contextPath}/storage/subamount/${licznik}'"/></td>
</tr>
</c:forEach>
</table>
You should be having your API controller like the one given below given that your UI is posting the data to your API / Controller (assuming you are using the latest version of Spring Boot). You have a #Get mapping which does not accept request payload in the body.
#RestController
public class StoragePageController {
#PostMapping(value = "/storage/subamount/{id}", produces = {"application/json"})
public String substractTheAmountValue(#PathVariable("id") int id, Model model) {
String amount_req = id;
System.out.println(amount_req);
return null;
}
}

Like/Dislike function with Spring Boot and Thymeleaf

I have a table in my Thymeleaf template which shows database data. I have additional two columns which contain Like and Dislike buttons for each row. I want to enable liking/disliking "posts". My idea was to simply increment Like/Dislike count in a database by updating database entity. So, in my template I got this:
<table id="css-serial" class="table table-striped table-inverse">
<tbody>
<tr>
<th>#</th>
<th>Kategorija</th>
<th>Vic</th>
<th>Likes</th>
<th>Dislikes</th>
<th>Razlika</th>
<th>Like</th>
<th>Dislike</th>
</tr>
<tr th:each="joke : ${jokes}">
<form method="POST" th:object="${updateJoke}" th:action="#{/}">
<td></td>
<td> <pre th:text="${joke.getCatName()}"></pre> </td>
<td> <div class="preforma" th:text="${joke.getContent()}" th:field="*{content}"></div> </td>
<td th:text="${joke.getLikes()}" th:field="*{likes}"></td>
<td th:text="${joke.getDislikes()}" th:field="*{dislikes}"></td>
<td th:text="${joke.likesDislikesSubtraction()}"></td>
<td><input type="submit" value="Svidja mi se" name="like"/></td>
<td><input type="submit" value="Ne svidja mi se" name="dislike"/></td>
</form>
</tr>
</tbody>
</table>
Controller GET and POST methods:
#RequestMapping(value="", method=RequestMethod.GET)
public String showJokes(Model model){
model.addAttribute("jokes", jokeService.listAllJokes());
return "jokestable";
}
#RequestMapping(params="like", method=RequestMethod.POST)
public String likeJoke(Joke joke, Model model){
model.addAttribute("updateJoke", joke);
jokeService.likeJoke(joke);
return showJokes(model);
}
#RequestMapping(params="dislike", method=RequestMethod.POST)
public String dislikeJoke(Joke joke, Model model){
model.addAttribute("updateJoke", joke);
jokeService.dislikeJoke(joke);
return showJokes(model);
}
Relevant methods in service layer:
public void likeJoke(Joke joke){
jokeRepository.likeJoke(joke.getContent());
}
public void dislikeJoke(Joke joke){
jokeRepository.dislikeJoke(joke.getContent());
}
Repository:
public interface JokeRepository extends CrudRepository<Joke, Long> {
Joke findByContent(String content);
#Modifying
#Query("UPDATE Joke j SET j.likes = j.likes+1 WHERE j.content=:content")
void likeJoke(#Param("content") String content);
#Modifying
#Query("UPDATE Joke j SET j.dislikes=j.dislikes+1 WHERE j.content=:content")
void dislikeJoke(#Param("content") String content);
}
This obviously doesn't work, and every time I hit the Like button, nothing happens, but when I go to IntelliJ, I see "Request method 'GET' not supported" (first time after refresh it shows this two times for each button, then every next time, only once). Is this solution even possible, or I have to change my approach? Any ideas?
P.S. Service class is annotated with #Transactional
If anyone wonders why do I
return showJokes(model);
it's because if I return template name, it doesn't show database data anymore when I hit the buttons, there's just empty table then (only th elements).
I suppose that possible problem could be that every Like button for every row is named the same, as well as Dislike buttons. But I don't know how to solve this.

How to bind an object list with thymeleaf?

I am having a lot of difficulty with POSTing back a form to the controller, which should contain simply an arraylist of objects that the user may edit.
The form loads up correctly, but when it's posted, it never seems to actually post anything.
Here is my form:
<form action="#" th:action="#{/query/submitQuery}" th:object="${clientList}" method="post">
<table class="table table-bordered table-hover table-striped">
<thead>
<tr>
<th>Select</th>
<th>Client ID</th>
<th>IP Addresss</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr th:each="currentClient, stat : ${clientList}">
<td><input type="checkbox" th:checked="${currentClient.selected}" /></td>
<td th:text="${currentClient.getClientID()}" ></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}" ></td>
</tr>
</tbody>
</table>
<button type="submit" value="submit" class="btn btn-success">Submit</button>
</form>
Above works fine, it loads up the list correctly. However, when I POST, it returns a empty object (of size 0). I believe this is due to the lack of th:field, but anyway here is controller POST method:
...
private List<ClientWithSelection> allClientsWithSelection = new ArrayList<ClientWithSelection>();
//GET method
...
model.addAttribute("clientList", allClientsWithSelection)
....
//POST method
#RequestMapping(value="/submitQuery", method = RequestMethod.POST)
public String processQuery(#ModelAttribute(value="clientList") ArrayList clientList, Model model){
//clientList== 0 in size
...
}
I have tried adding a th:field but regardless of what I do, it causes an exception.
I've tried:
...
<tr th:each="currentClient, stat : ${clientList}">
<td><input type="checkbox" th:checked="${currentClient.selected}" th:field="*{}" /></td>
<td th th:field="*{currentClient.selected}" ></td>
...
I cannot access currentClient (compile error), I can't even select clientList, it gives me options like get(), add(), clearAll() etc, so it things it should have an array, however, I cannot pass in an array.
I've also tried using something like th:field=${}, this causes runtime exception
I've tried
th:field = "*{clientList[__currentClient.clientID__]}"
but also compile error.
Any ideas?
UPDATE 1:
Tobias suggested that I need to wrap my list in a wraapper. So that's what I did:
ClientWithSelectionWrapper:
public class ClientWithSelectionListWrapper {
private ArrayList<ClientWithSelection> clientList;
public List<ClientWithSelection> getClientList(){
return clientList;
}
public void setClientList(ArrayList<ClientWithSelection> clients){
this.clientList = clients;
}
}
My page:
<form action="#" th:action="#{/query/submitQuery}" th:object="${wrapper}" method="post">
....
<tr th:each="currentClient, stat : ${wrapper.clientList}">
<td th:text="${stat}"></td>
<td>
<input type="checkbox"
th:name="|clientList[${stat.index}]|"
th:value="${currentClient.getClientID()}"
th:checked="${currentClient.selected}" />
</td>
<td th:text="${currentClient.getClientID()}" ></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}" ></td>
</tr>
Above loads fine:
Then my controller:
#RequestMapping(value="/submitQuery", method = RequestMethod.POST)
public String processQuery(#ModelAttribute ClientWithSelectionListWrapper wrapper, Model model){
...
}
The page loads correctly, the data is displayed as expected. If I post the form without any selection I get this:
org.springframework.expression.spel.SpelEvaluationException: EL1007E:(pos 0): Property or field 'clientList' cannot be found on null
Not sure why it's complaining
(In the GET Method it has: model.addAttribute("wrapper", wrapper);)
If I then make a selection, i.e. tick the first entry:
There was an unexpected error (type=Bad Request, status=400).
Validation failed for object='clientWithSelectionListWrapper'. Error count: 1
I'm guessing my POST controller is not getting the clientWithSelectionListWrapper. Not sure why, since I have set the wrapper object to be posted back via the th:object="wrapper" in the FORM header.
UPDATE 2:
I've made some progress! Finally the submitted form is being picked up by the POST method in controller. However, all the properties appear to be null, except for whether the item has been ticked or not. I've made various changes, this is how it is looking:
<form action="#" th:action="#{/query/submitQuery}" th:object="${wrapper}" method="post">
....
<tr th:each="currentClient, stat : ${clientList}">
<td th:text="${stat}"></td>
<td>
<input type="checkbox"
th:name="|clientList[${stat.index}]|"
th:value="${currentClient.getClientID()}"
th:checked="${currentClient.selected}"
th:field="*{clientList[__${stat.index}__].selected}">
</td>
<td th:text="${currentClient.getClientID()}"
th:field="*{clientList[__${stat.index}__].clientID}"
th:value="${currentClient.getClientID()}"
></td>
<td th:text="${currentClient.getIpAddress()}"
th:field="*{clientList[__${stat.index}__].ipAddress}"
th:value="${currentClient.getIpAddress()}"
></td>
<td th:text="${currentClient.getDescription()}"
th:field="*{clientList[__${stat.index}__].description}"
th:value="${currentClient.getDescription()}"
></td>
</tr>
I also added a default param-less constructor to my wrapper class and added a bindingResult param to POST method (not sure if needed).
public String processQuery(#ModelAttribute ClientWithSelectionListWrapper wrapper, BindingResult bindingResult, Model model)
So when an object is being posted, this is how it is looking:
Of course, the systemInfo is supposed to be null (at this stage), but the clientID is always 0, and ipAddress/Description always null. The selected boolean is correct though for all properties. I'm sure I've made a mistake on one of the properties somewhere. Back to investigation.
UPDATE 3:
Ok I've managed to fill up all the values correctly! But I had to change my td to include an <input /> which is not what I wanted... Nonetheless, the values are populating correctly, suggesting spring looks for an input tag perhaps for data mapping?
Here is an example of how I changed the clientID table data:
<td>
<input type="text" readonly="readonly"
th:name="|clientList[${stat.index}]|"
th:value="${currentClient.getClientID()}"
th:field="*{clientList[__${stat.index}__].clientID}"
/>
</td>
Now I need to figure out how to display it as plain data, ideally without any presence of an input box...
You need a wrapper object to hold the submited data, like this one:
public class ClientForm {
private ArrayList<String> clientList;
public ArrayList<String> getClientList() {
return clientList;
}
public void setClientList(ArrayList<String> clientList) {
this.clientList = clientList;
}
}
and use it as the #ModelAttribute in your processQuery method:
#RequestMapping(value="/submitQuery", method = RequestMethod.POST)
public String processQuery(#ModelAttribute ClientForm form, Model model){
System.out.println(form.getClientList());
}
Moreover, the input element needs a name and a value. If you directly build the html, then take into account that the name must be clientList[i], where i is the position of the item in the list:
<tr th:each="currentClient, stat : ${clientList}">
<td><input type="checkbox"
th:name="|clientList[${stat.index}]|"
th:value="${currentClient.getClientID()}"
th:checked="${currentClient.selected}" />
</td>
<td th:text="${currentClient.getClientID()}" ></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}" ></td>
</tr>
Note that clientList can contain null at
intermediate positions. Per example, if posted data is:
clientList[1] = 'B'
clientList[3] = 'D'
the resulting ArrayList will be: [null, B, null, D]
UPDATE 1:
In my exmple above, ClientForm is a wrapper for List<String>. But in your case ClientWithSelectionListWrapper contains ArrayList<ClientWithSelection>. Therefor clientList[1] should be clientList[1].clientID and so on with the other properties you want to sent back:
<tr th:each="currentClient, stat : ${wrapper.clientList}">
<td><input type="checkbox" th:name="|clientList[${stat.index}].clientID|"
th:value="${currentClient.getClientID()}" th:checked="${currentClient.selected}" /></td>
<td th:text="${currentClient.getClientID()}"></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}"></td>
</tr>
I've built a little demo, so you can test it:
Application.java
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
ClientWithSelection.java
public class ClientWithSelection {
private Boolean selected;
private String clientID;
private String ipAddress;
private String description;
public ClientWithSelection() {
}
public ClientWithSelection(Boolean selected, String clientID, String ipAddress, String description) {
super();
this.selected = selected;
this.clientID = clientID;
this.ipAddress = ipAddress;
this.description = description;
}
/* Getters and setters ... */
}
ClientWithSelectionListWrapper.java
public class ClientWithSelectionListWrapper {
private ArrayList<ClientWithSelection> clientList;
public ArrayList<ClientWithSelection> getClientList() {
return clientList;
}
public void setClientList(ArrayList<ClientWithSelection> clients) {
this.clientList = clients;
}
}
TestController.java
#Controller
class TestController {
private ArrayList<ClientWithSelection> allClientsWithSelection = new ArrayList<ClientWithSelection>();
public TestController() {
/* Dummy data */
allClientsWithSelection.add(new ClientWithSelection(false, "1", "192.168.0.10", "Client A"));
allClientsWithSelection.add(new ClientWithSelection(false, "2", "192.168.0.11", "Client B"));
allClientsWithSelection.add(new ClientWithSelection(false, "3", "192.168.0.12", "Client C"));
allClientsWithSelection.add(new ClientWithSelection(false, "4", "192.168.0.13", "Client D"));
}
#RequestMapping("/")
String index(Model model) {
ClientWithSelectionListWrapper wrapper = new ClientWithSelectionListWrapper();
wrapper.setClientList(allClientsWithSelection);
model.addAttribute("wrapper", wrapper);
return "test";
}
#RequestMapping(value = "/query/submitQuery", method = RequestMethod.POST)
public String processQuery(#ModelAttribute ClientWithSelectionListWrapper wrapper, Model model) {
System.out.println(wrapper.getClientList() != null ? wrapper.getClientList().size() : "null list");
System.out.println("--");
model.addAttribute("wrapper", wrapper);
return "test";
}
}
test.html
<!DOCTYPE html>
<html>
<head></head>
<body>
<form action="#" th:action="#{/query/submitQuery}" th:object="${wrapper}" method="post">
<table class="table table-bordered table-hover table-striped">
<thead>
<tr>
<th>Select</th>
<th>Client ID</th>
<th>IP Addresss</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr th:each="currentClient, stat : ${wrapper.clientList}">
<td><input type="checkbox" th:name="|clientList[${stat.index}].clientID|"
th:value="${currentClient.getClientID()}" th:checked="${currentClient.selected}" /></td>
<td th:text="${currentClient.getClientID()}"></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}"></td>
</tr>
</tbody>
</table>
<button type="submit" value="submit" class="btn btn-success">Submit</button>
</form>
</body>
</html>
UPDATE 1.B:
Below is the same example using th:field and sending back all other attributes as hidden values.
<tbody>
<tr th:each="currentClient, stat : *{clientList}">
<td>
<input type="checkbox" th:field="*{clientList[__${stat.index}__].selected}" />
<input type="hidden" th:field="*{clientList[__${stat.index}__].clientID}" />
<input type="hidden" th:field="*{clientList[__${stat.index}__].ipAddress}" />
<input type="hidden" th:field="*{clientList[__${stat.index}__].description}" />
</td>
<td th:text="${currentClient.getClientID()}"></td>
<td th:text="${currentClient.getIpAddress()}"></td>
<td th:text="${currentClient.getDescription()}"></td>
</tr>
</tbody>
When you want to select objects in thymeleaf, you dont actually need to create a wrapper for the purpose of storing a boolean select field. Using dynamic fields as per the thymeleaf guide with syntax th:field="*{rows[__${rowStat.index}__].variety}" is good for when you want to access an already existing set of objects in a collection. Its not really designed for doing selections by using wrapper objects IMO as it creates unnecessary boilerplate code and is sort of a hack.
Consider this simple example, a Person can select Drinks they like. Note: Constructors, Getters and setters are omitted for clarity. Also, these objects are normally stored in a database but I am using in memory arrays to explain the concept.
public class Person {
private Long id;
private List<Drink> drinks;
}
public class Drink {
private Long id;
private String name;
}
Spring controllers
The main thing here is that we are storing the Person in the Model so we can bind it to the form within th:object.
Secondly, the selectableDrinks are the drinks a person can select on the UI.
#GetMapping("/drinks")
public String getDrinks(Model model) {
Person person = new Person(30L);
// ud normally get these from the database.
List<Drink> selectableDrinks = Arrays.asList(
new Drink(1L, "coke"),
new Drink(2L, "fanta"),
new Drink(3L, "sprite")
);
model.addAttribute("person", person);
model.addAttribute("selectableDrinks", selectableDrinks);
return "templates/drinks";
}
#PostMapping("/drinks")
public String postDrinks(#ModelAttribute("person") Person person) {
// person.drinks will contain only the selected drinks
System.out.println(person);
return "templates/drinks";
}
Template code
Pay close attention to the li loop and how selectableDrinks is used to get all possible drinks that can be selected.
The checkbox th:field really expands to person.drinks since th:object is bound to Person and *{drinks} simply is the shortcut to referring to a property on the Person object. You can think of this as just telling spring/thymeleaf that any selected Drinks are going to be put into the ArrayList at location person.drinks.
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml"
xmlns:th="http://www.thymeleaf.org"
xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout" >
<body>
<div class="ui top attached segment">
<div class="ui top attached label">Drink demo</div>
<form class="ui form" th:action="#{/drinks}" method="post" th:object="${person}">
<ul>
<li th:each="drink : ${selectableDrinks}">
<div class="ui checkbox">
<input type="checkbox" th:field="*{drinks}" th:value="${drink.id}">
<label th:text="${drink.name}"></label>
</div>
</li>
</ul>
<div class="field">
<button class="ui button" type="submit">Submit</button>
</div>
</form>
</div>
</body>
</html>
Any way...the secret sauce is using th:value=${drinks.id}. This relies on spring converters. When the form is posted, spring will try recreate a Person and to do this it needs to know how to convert any selected drink.id strings into the actual Drink type. Note: If you did th:value${drinks} the value key in the checkbox html would be the toString() representation of a Drink which is not what you want, hence need to use the id!. If you are following along, all you need to do is create your own converter if one isn't already created.
Without a converter you will receive an error like
Failed to convert property value of type 'java.lang.String' to required type 'java.util.List' for property 'drinks'
You can turn on logging in application.properties to see the errors in detail.
logging.level.org.springframework.web=TRACE
This just means spring doesn't know how to convert a string id representing a drink.id into a Drink. The below is an example of a Converter that fixes this issue. Normally you would inject a repository in get access the database.
#Component
public class DrinkConverter implements Converter<String, Drink> {
#Override
public Drink convert(String id) {
System.out.println("Trying to convert id=" + id + " into a drink");
int parsedId = Integer.parseInt(id);
List<Drink> selectableDrinks = Arrays.asList(
new Drink(1L, "coke"),
new Drink(2L, "fanta"),
new Drink(3L, "sprite")
);
int index = parsedId - 1;
return selectableDrinks.get(index);
}
}
If an entity has a corresponding spring data repository, spring automatically creates the converters and will handle fetching the entity when an id is provided (string id seems to be fine too so spring does some additional conversions there by the looks). This is really cool but can be confusing to understand at first.

Pass multiple values from spring form jsp to spring controller on submit

I've a table which has multiple columns as in my database table. Few of the columns are editable and the values entered by the user should be updated back in the database on click of submit. For this Ive a foreach loop with value as HashMap of list of bean.
Below is my foreach loop:
<c:forEach items="${feeType.value}" var="feeItem" varStatus="feeVar">
<td >[b]<form:checkbox disabled="true" class="editable${ifeeCount}" path="includeFeeValue" value="${feeVar.index}"/> [/b]</td>
<td >${feeItem.feetypeId} </td>
<td >${feeItem.feeValue} </td>
<td >[b]<form:input class="editable${ifeeCount}" disabled="true" path="${feeItem.overridenFee}" value="${feeItem.overridenFee}"/>[/b]</td>
<td><form:errors path="overriddenFee" cssClass="error" /></td>
<td >${feeItem.lastUpdatedBy} </td>
<td >${feeItem.lastUpdatedDate} </td>
<td > ${feeItem.approvedBy}</td>
<td >${feeItem.approvalDate}</td>
<td align="left">[b]<form:input class="editable${ifeeCount}" disabled="true" path="feeComments[${feeVar.index}]"/>[/b]</td>
<td><form:errors path="feeComments" cssClass="error" /></td>
I'm iterating through a map called feeApprovalByFundId which is Map>. How do I get the updated values of the columns like checkbox, input box? I'm able to get in a String or String array but I won't know to which key was that mapped to. (Eg. Fund1 will have 10 fees - I will have under one hashmap key).
I tried iterating like this :
Collection<List<MyBaseBean>> newList = paswFeeMaintForm.getFeeApprovalByFundId().values();
for(List<MyBaseBean> myList: newList){
for(MyBaseBean myBean : myList){
System.out.println("Overriden fee : "+myBean.getOverridenFee());
}
}
The path in the form control binding is a string that represents a property binding expression. When the form is rendered, Spring knows what feeItem is due to the JSTL context in which the form control is being rendered. But on POST, that context is lost, so feeItem doesn't make sense.
Instead, given a form bean like this:
public class FormBean {
private Map<Integer, ChildBean> children = new HashMap<>();
public Map<Integer, ChildBean> getChildren() { return children; }
}
public class ChildBean {
private String name;
private String age;
}
And a controller like this:
#ModelAttribute("formBean")
public FormBean createFormBean() {
FormBean bean = new FormBean();
bean.add(new ChildBean("Joe", 5));
bean.add(new Childbean("Sam", 10));
}
#RequestMapping(...)
public String post(#ModelAttribute("formBean") FormBean formBean) { ... }
#RequestMapping(...)
public String get(#ModelAttribute("formBean") FormBean formBean) { ... }
In the view you would do this:
<form:form modelAttribute="formBean">
<c:forEach items="${formBean.children}" varStatus="s">
<form:input path="children[${s.index}].name" />
<form:input path="children[${s.index}].age" />
</c:forEach>
</form:form>
The rendered form elements would look something like:
<input type="text" name="children[0].name" />
<input type="text" name="children[0].age" />
<input type="text" name="children[1].name" />
<input type="text" name="children[1].age" />
Note that this is the standard indexed property syntax. Now, on the server side, there is enough context to determine which item in the collection should be modified.
For a map, the following no longer applies:
Also note that you don't have to return a list, but can specify the bean method to take an index and a single item, allowing you to define sparse collections (if you haven't constructed the collection ahead of time).

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