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("[email protected]", "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.showGET /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：
。。