Java JPA1.0是否有JPA fluent API/Critera API？I'；我正在使用OpenJPA

是否有用于查询构建的JPA1.0 fluent api/接口？我使用的是OpenJPA1.x，所以我只能使用JPA1

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我发现，但是它的Maven RePO不正常工作。

< P>如果你被JPA 1所困扰，那么考虑使用它，在JPA之上提供一个流畅的类型化API。您必须使用1.6.0之前的版本，即1.5.4（他们在1.6.0中切换到JPA2.0）。这是您最好的选择。

简短的回答是否。但这取决于您使用的提供商。例如，如果您使用的是Hibernate，则始终可以从Hibernate获取CriteriaAPI。然而，在JPA1.0中，这是不受支持的。在JPA2.0中，您可以将与JPA和Hibernate一起使用

总之，如果使用Hibernate，只需修改setter以返回实体：

@Entity(name = "Post")
@Table(name = "post")
public class Post {
 
    @Id
    private Long id;
 
    private String title;
 
    public Post() {}
 
    public Post(String title) {
        this.title = title;
    }
 
    @OneToMany(
        cascade = CascadeType.ALL, 
        orphanRemoval = true, 
        mappedBy = "post"
    )
    private List<PostComment> comments = new ArrayList<>();
 
    public Long getId() {
        return id;
    }
 
    public Post setId(Long id) {
        this.id = id;
        return this;
    }
 
    public String getTitle() {
        return title;
    }
 
    public Post setTitle(String title) {
        this.title = title;
        return this;
    }
 
    public List<PostComment> getComments() {
        return comments;
    }
 
    public Post addComment(PostComment comment) {
        comment.setPost(this);
        comments.add(comment);
        return this;
    }
}

@Entity(name = "PostComment")
@Table(name = "post_comment")
public class PostComment {
 
    @Id
    @GeneratedValue
    private Long id;
 
    private String review;
 
    private Date createdOn;
 
    @ManyToOne
    private Post post;
 
    public Long getId() {
        return id;
    }
 
    public PostComment setId(Long id) {
        this.id = id;
        return this;
    }
 
    public String getReview() {
        return review;
    }
 
    public PostComment setReview(String review) {
        this.review = review;
        return this;
    }
 
    public Date getCreatedOn() {
        return createdOn;
    }
 
    public PostComment setCreatedOn(Date createdOn) {
        this.createdOn = createdOn;
        return this;
    }
 
    public Post getPost() {
        return post;
    }
 
    public PostComment setPost(Post post) {
        this.post = post;
        return this;
    }
}

如果您关心JPA的可移植性，那么您可能不想违反Java Bean规范，在这种情况下，您需要添加Fluent接口方法以及常规setter：

@Entity(name = "Post")
@Table(name = "post")
public class Post {
 
    @Id
    private Long id;
 
    private String title;
 
    public Post() {}
 
    public Post(String title) {
        this.title = title;
    }
 
    @OneToMany(
        cascade = CascadeType.ALL, 
        orphanRemoval = true, 
        mappedBy = "post"
    )
    private List<PostComment> comments = new ArrayList<>();
 
    public Long getId() {
        return id;
    }
 
    public void setId(Long id) {
        this.id = id;
    }
 
    public Post id(Long id) {
        this.id = id;
        return this;
    }
 
    public String getTitle() {
        return title;
    }
 
    public void setTitle(String title) {
        this.title = title;
    }
 
    public Post title(String title) {
        this.title = title;
        return this;
    }
 
    public List<PostComment> getComments() {
        return comments;
    }
 
    public Post addComment(PostComment comment) {
        comments.add(comment.post(this));
        return this;
    }
}
 
@Entity(name = "PostComment")
@Table(name = "post_comment")
public class PostComment {
 
    @Id
    @GeneratedValue
    private Long id;
 
    private String review;
 
    private Date createdOn;
 
    @ManyToOne
    private Post post;
 
    public Long getId() {
        return id;
    }
 
    public PostComment setId(Long id) {
        this.id = id;
        return this;
    }
 
    public String getReview() {
        return review;
    }
 
    public void setReview(String review) {
        this.review = review;
    }
 
    public PostComment review(String review) {
        this.review = review;
        return this;
    }
 
    public Date getCreatedOn() {
        return createdOn;
    }
 
    public void setCreatedOn(Date createdOn) {
        this.createdOn = createdOn;
    }
 
    public PostComment createdOn(Date createdOn) {
        this.createdOn = createdOn;
        return this;
    }
 
    public Post getPost() {
        return post;
    }
 
    public void setPost(Post post) {
        this.post = post;
    }
 
    public PostComment post(Post post) {
        this.post = post;
        return this;
    }
}

---

这并不是很重要（至少我的答案不是这样），但你将Hibernate（标题中）和OpenJPA（正文中）混合在一起。谢谢，我将编辑以供将来参考QueryDSL还支持JDO、Java集合、SQL和Lucene。（有偏见的评论，因为我是Querydsl开发人员）

@Entity(name = "Post")
@Table(name = "post")
public class Post {
 
    @Id
    private Long id;
 
    private String title;
 
    public Post() {}
 
    public Post(String title) {
        this.title = title;
    }
 
    @OneToMany(
        cascade = CascadeType.ALL, 
        orphanRemoval = true, 
        mappedBy = "post"
    )
    private List<PostComment> comments = new ArrayList<>();
 
    public Long getId() {
        return id;
    }
 
    public void setId(Long id) {
        this.id = id;
    }
 
    public Post id(Long id) {
        this.id = id;
        return this;
    }
 
    public String getTitle() {
        return title;
    }
 
    public void setTitle(String title) {
        this.title = title;
    }
 
    public Post title(String title) {
        this.title = title;
        return this;
    }
 
    public List<PostComment> getComments() {
        return comments;
    }
 
    public Post addComment(PostComment comment) {
        comments.add(comment.post(this));
        return this;
    }
}
 
@Entity(name = "PostComment")
@Table(name = "post_comment")
public class PostComment {
 
    @Id
    @GeneratedValue
    private Long id;
 
    private String review;
 
    private Date createdOn;
 
    @ManyToOne
    private Post post;
 
    public Long getId() {
        return id;
    }
 
    public PostComment setId(Long id) {
        this.id = id;
        return this;
    }
 
    public String getReview() {
        return review;
    }
 
    public void setReview(String review) {
        this.review = review;
    }
 
    public PostComment review(String review) {
        this.review = review;
        return this;
    }
 
    public Date getCreatedOn() {
        return createdOn;
    }
 
    public void setCreatedOn(Date createdOn) {
        this.createdOn = createdOn;
    }
 
    public PostComment createdOn(Date createdOn) {
        this.createdOn = createdOn;
        return this;
    }
 
    public Post getPost() {
        return post;
    }
 
    public void setPost(Post post) {
        this.post = post;
    }
 
    public PostComment post(Post post) {
        this.post = post;
        return this;
    }
}

doInJPA(entityManager -> {
    Post post = new Post()
    .id(1L)
    .title("High-Performance Java Persistence")
    .addComment(new PostComment()
        .review("Awesome book")
        .createdOn(Timestamp.from(
            LocalDateTime.now().minusDays(1).toInstant(ZoneOffset.UTC))
        )
    )
    .addComment(new PostComment()
        .review("High-Performance Rocks!")
        .createdOn(Timestamp.from(
            LocalDateTime.now().minusDays(2).toInstant(ZoneOffset.UTC))
        )
    )
    .addComment(new PostComment()
        .review("Database essentials to the rescue!")
        .createdOn(Timestamp.from(
            LocalDateTime.now().minusDays(3).toInstant(ZoneOffset.UTC))
        )
    );
    entityManager.persist(post);
});