PlayFramework完整实现一个APP（八)

创建Tag标签

1.创建Model

@Entity
@Table(name = "blog_tag")public class Tag extends Model implements Comparable<Tag> {
public String name;
PRivate Tag(String name) { this.name = name;
}
public String toString() { return name;
}
public int compareTo(Tag otherTag) { return name.compareTo(otherTag.name);
}
public static Tag findOrCreateByName(String name) {
Tag tag = Tag.find("byName", name).first(); if(tag == null) {
tag = new Tag(name);
} return tag;
}}

2.Post类添加Tag属性

@ManyToMany(cascade = CascadeType.PERSIST)public Set<Tag> tags;public Post(User author, String title, String content) {
this.comments = new ArrayList<Comment>(); this.tags = new TreeSet<Tag>(); this.author = author; this.title = title; this.content = content; this.postedAt = new Date();
}

　

3.Post类添加方法

关联Post和Tag

public Post tagItWith(String name) {
tags.add(Tag.findOrCreateByName(name)); return this;
}

　　

返回关联指定Tag的Post集合

public static List<Post> findTaggedWith(String... tags) { return Post.find( "select distinct p from Post p join p.tags as t where t.name in (:tags) group by p.id, p.author, p.title, p.content,p.postedAt having count(t.id) = :size"
).bind("tags", tags).bind("size", tags.length).fetch();
}

4.写测试用例

@Testpublic void testTags() { // Create a new user and save it
User bob = new User("[e-mail]", "secret", "Bob").save();
// Create a new post
Post bobPost = new Post(bob, "My first post", "Hello world").save();
Post anotherBobPost = new Post(bob, "Hop", "Hello world").save();
// Well
assertEquals(0, Post.findTaggedWith("Red").size());
// Tag it now
bobPost.tagItWith("Red").tagItWith("Blue").save();
anotherBobPost.tagItWith("Red").tagItWith("Green").save();
// Check
assertEquals(1, Post.findTaggedWith("Red", "Blue").size());
assertEquals(1, Post.findTaggedWith("Red", "Green").size());
assertEquals(0, Post.findTaggedWith("Red", "Green", "Blue").size());
assertEquals(0, Post.findTaggedWith("Green", "Blue").size()); }

测试Tag

5.继续修改Tag类，添加方法

public static List<Map> getCloud() {
List<Map> result = Tag.find( "select new map(t.name as tag, count(p.id) as pound) from Post p join p.tags as t group by t.name order by t.name"
).fetch(); return result;
}

6.将Tag添加到页面上

/yabe/conf/initial-data.yml 添加预置数据

Tag(play):
name: Play

Tag(architecture):
name: Architecture

Tag(test):
name: Test

Tag(mvc):
name: MVC

Post(jeffPost):
title: The MVC application
postedAt: 2009-06-06
author: jeff
tags:
- play
- architecture
- mvc
content: >
A Play

　　

7.修改display.html将tag显示出来

<div class="post-metadata">
<span class="post-author">by ${_post.author.fullname}</span>,
<span class="post-date">${_post.postedAt.format('dd MMM yy')}</span>
#{if _as != 'full'}
<span class="post-comments">
| ${_post.comments.size() ?: 'no'}
comment${_post.comments.size().pluralize()}
#{if _post.comments}
, latest by ${_post.comments[0].author}
#{/if}
</span>
#{/if}
#{elseif _post.tags}
<span class="post-tags">
- Tagged
#{list items:_post.tags, as:'tag'}
<a href="#">${tag}</a>${tag_isLast ? '' : ', '}
#{/list}
</span>
#{/elseif}
</div>

　　

8.添加listTagged 方法（Application Controller）

点击Tagged，显示所有带有Tag的Post列表

public static void listTagged(String tag) {
List<Post> posts = Post.findTaggedWith(tag);
render(tag, posts);
}

9.修改display.html，Tag显示

- Tagged
#{list items:_post.tags, as:'tag'}
<a href="@{Application.listTagged(tag.name)}">${tag}</a>${tag_isLast ? '' : ', '}
#{/list}

　　

10.添加Route

GET /posts/{tag} Application.listTagged

　　

现在有两条Route规则URL无法区分

GET /posts/{id} Application.show
GET /posts/{tag} Application.listTagged

为{id}添加规则

GET /posts/{<[0-9]+>id} 　　　　Application.show

　　

11.添加Post list页面，有相同Tag的Post

创建/app/views/Application/listTagged.html

#{extends 'main.html' /}
#{set title:'Posts tagged with ' + tag /}

*{********* Title ********* }*
#{if posts.size()>1}
<h3>There are ${posts.size()} posts tagged ${tag}</h3>
#{/if}
#{elseif posts}
<h3>There is 1 post tagged '${tag}'</h3>
#{/elseif}
#{else}
<h3>No post tagged '${tag}'</h3>
#{/else}

*{********* Posts list *********}*
<div class="older-posts">
#{list items:posts, as:'post'}
#{display post:post, as:'teaser' /}
#{/list}
</div>

　　

效果：

以上就是PlayFramework完整实现一个APP（八)的内容，更多相关内容请关注PHP中文网（www.php.cn）！