如何访问jpa元模型中的子属性where子句中的

Question

我有两个实体之间存在关系。

public class Client implements Serializable { 
private static final long serialVersionUID = 1L; 

@Id 
@GeneratedValue 
private Integer id; 

@NotNull 
@Size(min = 3, max = 25) 
private String firstName; 

@NotNull 
@Size(min = 3, max = 25) 
private String lastName; 

private String login; 

private String password; 

@OneToMany(mappedBy = "client") 
private List<Project> projects; 
} 

和

public class Project implements Serializable { 
private static final long serialVersionUID = 4762714047114442539L; 

@Id 
@GeneratedValue 
private Integer id; 

private String name; 

@Temporal(TemporalType.TIMESTAMP) 
private Date startDate; 

@ManyToOne 
@JoinColumn 
private Client client; 
} 

我想用jpametamodel和标准的API做了一个查询。就像这样：

CriteriaBuilder cb = em.getCriteriaBuilder(); 
CriteriaQuery<Project> q = cb.createQuery(Project.class); 
Root<Project> projects = q.from(Project.class); 
q.where(cb.equal(projects.get(Project_.client), clientId)); 

问题对我来说，我不知道怎么去访问这个字符串客户的“ID”属性：

q.where(cb.equal(projects.get(Project_.client), clientId)); 

我想要得到的东西像

q.where(cb.equal(projects.get("client.id"), clientId)); 

但与jpametamodel。有可能的？ :)

Answer 1

试过这样的事情？

projects.get(Project_.client).get(Client_.id);