How to handle data from form in Spring MVC

Question

How to handle data from form in Spring MVC

1.2k views Asked by Constantine Gladky At 24 November 2024 at 00:23

I have jsp that show all posts in blog

<body>
    <table>
        <c:forEach var="post" items="${posts}">
            <tr>
                <td>${post.id}</td>
                <td>${post.text}</td>
                <td><a href="authors?name=${post.author}">Show author</a></td>
            </tr>
        </c:forEach>
    </table>

    <div>
        <a href="posts/get.json">JSON</a> <a href="posts/get.xml">XML</a>
    </div>

</body>

I have controller to handle it

@Controller
public class PostsController {

    @Autowired
    private PostDAO postDao;

    @RequestMapping("/posts")
    public String showAllPosts(ModelMap model) {

        List<Post> posts = postDao.findAll();
        model.addAttribute("posts", posts);
        return "posts";
    }

    @RequestMapping("/posts/get")
    public List<Post> getAllPosts() {
        List<Post> posts = postDao.findAll();
        return posts;
    }

}

Now I want to add form to save new post.

I add form in my jsp

<form:form method="POST" action="/posts/add" modelAttribute="post">
        <table>
            <tr>
                <td><form:label path="id">Id:</form:label></td>
                <td><form:input path="id" /></td>
            </tr>
            <tr>
                <td><form:label path="text">Text:</form:label></td>
                <td><form:input path="text" /></td>
            </tr>
        </table>
        <input type="submit" value="Save" />
    </form:form>

Also I add to controller.

@RequestMapping( value = "/posts/add", method = RequestMethod.POST)
    public String saveAdd(@ModelAttribute("post") Post post, ModelMap model) {

        model.addAttribute("posts", postDao.addPost(post));

        return "posts";
    }

Domain model Post.java

public class Post {

    private int id;

    private String author;

    private String text;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

}

But I get

 java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'post' available as request attribute

Original Q&A

There are 2 answers

Md Rahman On 11 April 2014 at 10:22

From Controller:

@RequestMapping(value = "createcustomer",method = RequestMethod.GET)
    public String customer(Model model)
    {
        Customer cus=new Customer();
        cus.setCustomerNumber("Test");
        model.addAttribute("customer",cus);
        return "createcustomer";
    }

In View:

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %> 

<div class="cl">    
   <form:form commandName="customer" method="POST">

      <p>Name: <c:out value="${customer.CustomerNumber}"></c:out></p>

   </form:form>
<div>

Output:

Name: Test

**Will Keeling** · Accepted Answer · 2013-12-13 11:23:46

Because your JSP contains the new form for adding a new post, it will need the model attribute post to be present when you go to /posts.

@RequestMapping("/posts")
public String showAllPosts(ModelMap model) {

    List<Post> posts = postDao.findAll();
    model.addAttribute("post", new Post()); // Add empty form backing object
    model.addAttribute("posts", posts);
    return "posts";
}

You could even split out model creation to a separate method if you find you're having to create the model in multiple places. This will ensure that its always available.

@ModelAttribute("post")
public Post createModel() {
    return new Post();
}

TechQA.

How to handle data from form in Spring MVC

There are 2 answers

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