创建Tag标签
1.创建Model
@Entity
@Table(name="blog_tag")publicclassTag extends Model implements Comparable<Tag>{publicString name;PRivateTag(String name) {this.name =name;
}publicString toString() {returnname;
}publicintcompareTo(Tag otherTag) {returnname.compareTo(otherTag.name);
}publicstaticTag findOrCreateByName(String name) {
Tag tag= Tag.find("byName", name).first();if(tag ==null) {
tag=newTag(name);
}returntag;
}}
2.Post类添加Tag属性
@ManyToMany(cascade =CascadeType.PERSIST)publicSet<Tag>tags;publicPost(User author, String title, String content) {this.comments =newArrayList<Comment>();this.tags =newTreeSet<Tag>();this.author =author;this.title =title;this.content =content;this.postedAt =newDate();
}
3.Post类添加方法
关联Post和Tag
publicPost tagItWith(String name) {
tags.add(Tag.findOrCreateByName(name));returnthis;
}
返回关联指定Tag的Post集合
publicstaticList<Post>findTaggedWith(String... tags) {returnPost.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
@TestpublicvoidtestTags() {//Create a new user and save itUser bob =newUser("bob@Gmail.com", "secret", "Bob").save();//Create a new postPost bobPost =newPost(bob, "My first post", "Hello world").save();
Post anotherBobPost=newPost(bob, "Hop", "Hello world").save();//WellassertEquals(0, Post.findTaggedWith("Red").size());//Tag it nowbobPost.tagItWith("Red").tagItWith("Blue").save();
anotherBobPost.tagItWith("Red").tagItWith("Green").save();//CheckassertEquals(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
publicstaticList<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();returnresult;
}
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 MVCapplicationpostedAt: 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>${tag_isLast ? '' : ', '}
#{/list}
</span>
#{/elseif}
</div>
8.添加listTagged 方法（Application Controller）
点击Tagged，显示所有带有Tag的Post列表
publicstaticvoidlistTagged(String tag) {
List<Post> posts =Post.findTaggedWith(tag);
render(tag, posts);
}
9.修改display.html，Tag显示
- Tagged
#{list items:_post.tags, as:'tag'}
<a href="@{Application.listTagged(tag.name)}">${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：
。。