1.添加Post類
package models;import java.util.*;import javax.persistence.*;import play.db.jpa.*;@Entity@Table(name = "blog_post")public class Post extends Model { public String title; public Date postedAt; @Lob public String content; @ManyToOne public User author; public Post(User author, String title, String content) { this.author = author; this.title = title; this.content = title; }}
@Lob 標識,字段是一個large text的類型,@ManyToOne 標識每個Post只能對應一個User,一個User可以對應多個Post
2. 添加測試用例
@Test public void createPost() { // Create a new user and save it User user = new User("bob@Gmail.com", "####", "Bob").save(); // Create a new post new Post(user, "My first post", "Hello world").save(); // Test that the post has been created assertEquals(1, Post.count()); // Retrieve all posts created by user List<Post> posts = Post.find("byAuthor", user).fetch(); // Tests assertEquals(1, posts.size()); Post firstPost = posts.get(0); assertNotNull(firstPost); assertEquals(user, firstPost.author); assertEquals("My first post", firstPost.title); assertEquals("Hello world", firstPost.content); assertNotNull(firstPost.postedAt); }
3.添加Comment類
@Entitypublic class Comment extends Model { public String author; public Date postedAt; @Lob public String content; @ManyToOne public Post post; public Comment(Post post, String author, String content) { this.post = post; this.author = author; this.content = content; this.postedAt = new Date(); }}
4.添加測試用例
@Testpublic void postComments() { // Create a new user and save it User bob = new User("bob@gmail.com", "secret", "Bob").save(); // Create a new post Post bobPost = new Post(bob, "My first post", "Hello world").save(); // Post a first comment new Comment(bobPost, "Jeff", "Nice post").save(); new Comment(bobPost, "Tom", "I knew that !").save(); // Retrieve all comments List<Comment> bobPostComments = Comment.find("byPost", bobPost).fetch(); // Tests assertEquals(2, bobPostComments.size()); Comment firstComment = bobPostComments.get(0); assertNotNull(firstComment); assertEquals("Jeff", firstComment.author); assertEquals("Nice post", firstComment.content); assertNotNull(firstComment.postedAt); Comment secondComment = bobPostComments.get(1); assertNotNull(secondComment); assertEquals("Tom", secondComment.author); assertEquals("I knew that !", secondComment.content); assertNotNull(secondComment.postedAt);}
5.在Post類中添加Comment
@OneToMany(mappedBy="post", cascade=CascadeType.ALL)public List<Comment> comments; public Post(User author, String title, String content) { this.comments = new ArrayList<Comment>(); this.author = author; this.title = title; this.content = title; this.postedAt = new Date();}
6.在Post類中添加方法
public Post addComment(String author, String content) { Comment newComment = new Comment(this, author, content).save(); this.comments.add(newComment); this.save(); return this;}
7.添加測試用例
@Testpublic void useTheCommentsRelation() { // Create a new user and save it User bob = new User("bob@gmail.com", "secret", "Bob").save(); // Create a new post Post bobPost = new Post(bob, "My first post", "Hello world").save(); // Post a first comment bobPost.addComment("Jeff", "Nice post"); bobPost.addComment("Tom", "I knew that !"); // Count things assertEquals(1, User.count()); assertEquals(1, Post.count()); assertEquals(2, Comment.count()); // Retrieve Bob's post bobPost = Post.find("byAuthor", bob).first(); assertNotNull(bobPost); // Navigate to comments assertEquals(2, bobPost.comments.size()); assertEquals("Jeff", bobPost.comments.get(0).author); // Delete the post bobPost.delete(); // Check that all comments have been deleted assertEquals(1, User.count()); assertEquals(0, Post.count()); assertEquals(0, Comment.count());}
運行Test,如有異常會出現下方提示
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