java-thymeleaf“尝试重新发布已经创建的信息”

Question

我已经创建了一个用于创建博客文章的应用。现在，我正在尝试更新应用程序以执行CRUD功能。原始应用程序仍在工作，其中包括一个屏幕截图。

Blog Home screen

通过他们我可以登录和注销，或者可以创建新帖子。当我选择一个给定的用户名时，应按用户名列出所有帖子。见下文：

Blog posts by username

从这里我可以选择一个特定的博客文章，该博客文章将按用户名及其名称拉出该博客文章。另外，在此屏幕中，我修改了百里香叶以允许我编辑博客文章或删除博客文章。见下文：

Blog post by username and uid

当我单击“编辑”时，这是该操作的结果。我想做的是将信息从单个帖子页面传递到新的百里香模板中，并允许对信息进行编辑。完成编辑的信息后，继续并重新保存信息。见下文：

Blog posts edit by username and uid

我想知道我做错了什么。我将包含我的postcontroller.java，editpost.html，post.html，postdao.java。

package org.launchcode.blogz.controllers;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.launchcode.blogz.models.Post;
import org.launchcode.blogz.models.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class PostController extends AbstractController {

    @RequestMapping(value = "/blog/newpost", method = RequestMethod.GET)
    public String newPostForm() {
        return "newpost";
    }

    @RequestMapping(value = "/blog/newpost", method = RequestMethod.POST)
    public String newPost(HttpServletRequest request, Model model) {

        // TODO - implement newPost
        // get request parameters
        String title = request.getParameter("title");
        String body = request.getParameter("body");

        // get user from their session
        HttpSession newSession = request.getSession();
        User author = getUserFromSession(newSession);

        // validate parameters
        // if valid, create new Post
        // if not valid, send back to the form, with an error message

        if (title == null || title.isEmpty()) {
            model.addAttribute("error", "The title is missing from this post. Please enter a title.");
            return "newpost";
        }

        if (body == null || body.isEmpty()) {
            model.addAttribute("title", title);
            model.addAttribute("error", "The body of the post needs some content. Please enter some content for this post.");
            return "newpost";
        }

        // save the user's post
        Post post = new Post(title, body, author);
        postDao.save(post);

        // TODO - this redirect should go to the new post's page
        return "redirect:/blog/" + author.getUsername() + "/" + post.getUid();
    }

    @RequestMapping(value = "/blog/{username}/{uid}", method = RequestMethod.GET)
    public String singlePost(@PathVariable String username, @PathVariable int uid, Model model) {

        // TODO - implement singlePost
        // get the given parameters

        Post post = postDao.findByUid(uid);

        // get the given post
        // pass the post into the template

        model.addAttribute("error", "");
        model.addAttribute("post", post);

        return "post";
    }

    @RequestMapping(value = "/blog/{username}", method = RequestMethod.GET)
    public String userPosts(@PathVariable String username, Model model) {

        // TODO - implement userPosts
        // get all of the user's posts

        User user = userDao.findByUsername(username);
        List<Post> posts = user.getPosts();

        // pass the posts into the template

        model.addAttribute("posts", posts);

        return "blog";
    }

    @RequestMapping(value = "/blog/editpost/{username}/{uid}", method = RequestMethod.GET)
    public String editPostForm(@PathVariable String username, @PathVariable int uid, Model model){

        return "editPost";
    }

    @RequestMapping(value = "/blog/editpost/{username}/{uid}", method = RequestMethod.POST)
    public String editPost(HttpServletRequest request, @PathVariable String username, @PathVariable int id, Model model) {

        // TODO - implement newPost
        // get request parameters
        String title = request.getParameter("title");
        String body = request.getParameter("body");

        // get user from their session
        HttpSession newSession = request.getSession();
        User author = getUserFromSession(newSession);

        // validate parameters
        // if valid, create new Post
        // if not valid, send back to the form, with an error message

        if (title == null || title.isEmpty()) {
            model.addAttribute("error", "The title is missing from this post. Please enter a title.");
            return "editPost";
            }

        if (body == null || body.isEmpty()) {
            model.addAttribute("title", title);
            model.addAttribute("error", "The body of the post needs some content. Please enter some content for this post.");
            return "editPost";
            }

        // save the user's post
        Post post = new Post(title, body, author);
        postDao.save(post);

        // TODO - this redirect should go to the new post's page
        return "redirect:/blog/" + author.getUsername() + "/" + post.getUid();
    }

//    @RequestMapping(value = "/blog/deletepost")
//    public String deleteByUid(@PathVariable("uid") long id, Model model) {
//        String deleteSQL = "DELETE post WHERE uid = ${post.uid}";
//        PreparedStatement preparedStatement = dbConnection.prepareStatement(deleteSQL);
//        // execute delete SQL stetement
//        preparedStatement.executeUpdate();
//        return "index";
//    }

}

上面的代码是我的控制器

下一个是我的editpost.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org/">
<head th:replace="template :: dochead">
</head>
<body>

    <div th:replace="template :: navigation"></div>

    <h2>Edit Post</h2>

    <form method="post" th:object="$[post}">
        <label>
            <div>title</div>
            <input type="text" name="title" class="post-title" th:text="${post.title}"></input>"post-title" th:text="${post.title}"
        </label>
        <label>
            <div>post</div>
            <textarea name="body" class="post-body" th:text="${post.body}"></textarea>
        </label>
        <div class="error" th:text="${error}"></div>
        <button type="submit">Save</button>
    </form>

</body>
</html>

下一个代码段将是我的post.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org/">
<head th:replace="template :: dochead">
</head>
<body>

    <div th:replace="template :: navigation"></div>

    <h2>A Single Post</h2>

    <!-- TODO - display a single blog post -->
    <h3 class="post-title" th:text="${post.title}"></h3>
    <p class="post-body" th:text="${post.body}"></p>

    <div class="error" th:text="${error}"></div>

    <a href="@{/blog/editpost/${username}/${uid}">Edit</a>
    <a href="/blog/deletepost">Delete</a>

    <p class="footer">This post was created by <a th:href="'/blog/' + ${post.author.username}" th:text="${post.author.username}"></a> on the date <em><span th:text="${#dates.format(post.modified, 'yyyy-MM-dd hh:mm:ss')}"></span></em></p>

</body>
</html>

最后的代码段将是我的postdao.java

package org.launchcode.blogz.models.dao;

import java.util.List;

import javax.transaction.Transactional;

import org.launchcode.blogz.models.Post;
import org.launchcode.blogz.models.User;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Transactional
@Repository
public interface PostDao extends CrudRepository<Post, Integer> {

    List<Post> findByAuthor(User authorId);

    // TODO - add method signatures as needed

    Post findByUid(int uid);
    List<Post> findAll();
    void deleteByUid(int uid);

}

我希望有人能帮助我，对此我将不胜感激。

Answer 1

您的editpost.html出现错误。按下“编辑”按钮后，请注意您的浏览器URL，它是

  

localhost：8080 / blog / jfreynolds / @ {/ blog / editpost / $ {username} / $ {uid}

代替

  

localhost：8080 / blog / editpost / jreynolds / 2

只需在下面的href前面添加“ ：”，即可使用您的表达式。

<a th:href="@{/blog/editpost/${username}/${uid}">Edit</a>