CODEWITHSUNDEEP
javaarraysmavenspring-bootthymeleaf
Moe
Moe

Reputation: 129

List with springboot and thymeleaf

I am trying to get a list of objects that are sent to the server from the html form as parameters for my list, then I will loop through those entries and then return them through the springboot th:each. But it doesn't seem to be working at all. On load the form appears but when I enter a value in it, then it returns an error page and the URL however turns: 

http://localhost:8080/@%7B/%7D?%24%7Bcontent%7D=hello

this output in eclipse says:

Expression "content" is not valid: only variable expressions ${...} or selection expressions *{...} are allowed in Spring field bindings

Note: content here is the value property in my form. My controller looks like this:

@Controller
public HelloList() {
    this.addUs = new ArrayList <>();
}

@RequestMapping("/")
public String getlist(@RequestParam (required = false) String content, Model model) {
    if (content != null && !content.trim().isEmpty()) {
        this.addUs.add(content);
    }

    model.addAttribute("list",addUs);
    return "index";
}

the index.html looks like this

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Insert title here</title>
</head>
<body>
<div>
    <ul>
        <li th:each="amHere: ${addUs}">
            <span th:text="${amHere}">hello! world</span>
        </li>
    </ul>

    <form action="@{/}" method="GET">
        <input type="text" name="content"/>
        <input type="submit" value="Submit"/>
    </form>
</div>
</body>
</html>

This might be a duplicate but it seems like most of the solutions I came across are not helping. So any help is mostly appreciated. Thank you in advance.

Upvotes: 1

Views: 882

Answers (2)

Moe
Moe

Reputation: 129

Turns out I was missing the initialization of my list in the constructor. I initialized the list by adding a value to it first in the constructor like this.

this.addUs.add("Hello World");

Because the @RequestMapping is mapped to the home path in my case index.html, any request gets sent there automatically. working example

Upvotes: 1

Metroids
Metroids

Reputation: 20487

action = "@{/}" should be th:action="@{/}". That's the reason you're seeing the weird url (because it's url encoding @{/}). Thymeleaf only evaluates expressions that start with th:.

I'm not sure about the other error. It looks like the html you've pasted doesn't match up with the error you are getting.

If you urldecode http://localhost:8080/@%7B/%7D?%24%7Bcontent%7D=hello, you get http://localhost:8080/@{/}?${content}=hello, which doesn't line up with your form.

Upvotes: 0

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