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POHibernate @OneToMany Relationship Causes Infinite Loop Or Empty Entries in JSON Result
 

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    <p>I have two entities, an entity "movie" and an entity "Clip" each clip belongs to one movie and a movie can have multiple clips.</p> <p>My code looks like:</p> <pre><code>Movie.java @OneToMany(mappedBy = "movie", targetEntity = Clip.class, cascade = CascadeType.ALL, fetch = FetchType.EAGER) private Set&lt;Clip&gt; clips = new HashSet&lt;Clip&gt;(); Clip.java @ManyToOne @JoinColumn(name="movie_id") private Movie movie; </code></pre> <p>The tables are being generated and each Clip has a column "movie_id" but this causes my application to end up in an infinite loop when I'm requesting Data</p> <pre><code> @Path("/{id:[0-9][0-9]*}") @GET @Produces(MediaType.APPLICATION_JSON) public Movie lookupMovieById(@PathParam("id") long id) { return em.find(Movie.class, id); } result: {"id":1,"version":1,"name":"MGS Walkthrough","filename":"video.mp4","movieCategories":[{"id":1,"version":1,"name":"Walkthrough"}],"clips":[{"id":1,"version":1,"name":"MGS Walkthrough P1","keywords":null,"movie":{"id":1,"version":1,"name":"MGS Walkthrough","filename":"video.mp4","movieCategories":[{"id":1,"version":1,"name":"Walkthrough"}],"clips":[{"id":1,"version":1,"name":"MGS Walkthrough P1","keywords":null,"movie":{"id":1,"version":1,"name":"MGS Walkthrough","filename":"video.mp4","movieCategories":[{"id":1,"version":1,"name":"Walkthrough"}],"clips":[{"id":1,"version":1,"name":"M... </code></pre> <p>It's the same result when I'm requesting a clip.</p> <p>When I change it to a @ManyToMany relationship there won't be any problems like that, but that's not what I need here. Can you help me? Setting fetchType to Lazy didn't work.</p> <p>Edit: I'm using the current JBoss development studio</p> <p>Edit: </p> <p>I "solved" this, by reading this article:</p> <p><a href="http://blog.jonasbandi.net/2009/02/help-needed-mapping-bidirectional-list.html">http://blog.jonasbandi.net/2009/02/help-needed-mapping-bidirectional-list.html</a></p> <p>"To map a bidirectional one to many, with the one-to-many side as the owning side, you have to remove the mappedBy element and set the many to one @JoinColumn as insertable and updatable to false. This solution is obviously not optimized and will produce some additional UPDATE statements."</p> <p>when I request a movie I get the following answer:</p> <p>{"id":1,"version":1,"name":"MGS Walkthrough","filename":"video.mp4","movieCategories":[{"id":1,"version":1,"name":"Walkthrough"}],"clips":[],"description":"Trailer zu mgs4"}</p> <p>the entry "clips" still appears. Is this still the wrong solution or do I just have to live with this?</p>
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