我有3个类,分别是User、Role和UserRole。我想获取UserRole的数据,但总是返回NULL。
这是用户类。
@NodeEntity
public class User {
@GraphId
Long id;
@NotNull
private String username;
@NotNull
private String password;
@NotNull
private String firstName;
@NotNull
private String lastName;
@NotNull
private String role;
@NotNull
private Boolean active;
@Relationship(type = "HAS_ROLE", direction = Relationship.OUTGOING)
private Set<UserRole> userRoles;
public User() {
super();
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public Boolean getActive() {
return active;
}
public void setActive(Boolean active) {
this.active = active;
}
public Iterable<UserRole> getUserRoles() {
return userRoles;
}
public void setUserRoles(Set<UserRole> userRoles) {
this.userRoles = userRoles;
}
}
这是我的角色类
@NodeEntity
public class Role {
@GraphId
Long id;
@NotNull
String name;
@Relationship(type = "HAS_ROLE",direction = Relationship.OUTGOING)
@JsonIgnore
private Set<UserRole> userRoles;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<UserRole> getUserRoles() {
return userRoles;
}
public void setUserRoles(Set<UserRole> userRoles) {
this.userRoles = userRoles;
}
public Role() {
super();
}
}
这是我的 UserRole 类
@RelationshipEntity(type = "HAS_ROLE")
public class UserRole {
@GraphId
Long id;
@StartNode
@Relationship(type="HAS_ROLE", direction=Relationship.INCOMING)
User user;
@EndNode
@Relationship(type="HAS_ROLE", direction=Relationship.INCOMING)
Role role;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Role getRole() {
return role;
}
public void setRole(Role role) {
this.role = role;
}
public UserRole(User user, Role role) {
super();
this.user = user;
this.role = role;
}
public UserRole() {
super();
}
}
我想显示所有用户数据,但结果总是显示 userRoles NULL。我正在使用 findAll(1) 和 findAll(2) 但没有什么不同。
与SDN 3不同,我们只在字段中添加@Fetch。在SDN 4中,没有@Fetch注释。我如何获取所有数据?
更新!!
我像 Luanne 答案一样更改了类,并修改了 User 类,如下所示:
@NodeEntity
public class User {
@GraphId
Long id;
@NotNull
private String username;
@NotNull
private String password;
@NotNull
private String firstName;
@NotNull
private String lastName;
@NotNull
private String role;
@NotNull
private Boolean active;
@Relationship(type = "HAS_ROLE")
private Set<UserRole> userRoles;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public Boolean getActive() {
return active;
}
public void setActive(Boolean active) {
this.active = active;
}
@Relationship(type = "HAS_ROLE")
public Set<UserRole> getUserRoles() {
return userRoles;
}
@Relationship(type = "HAS_ROLE")
public void setUserRoles(Set<UserRole> userRoles) {
this.userRoles = userRoles;
}
public User(){
super();
}
}
保存数据并显示后,角色显示如下:
[{"id":27,"username":"daviduck123","password":"admin","firstName":"David","lastName":"Vincent","role":"admin","active":null,"roles":{"id":"29","name":"ROLE_ADMIN"}}]
但之后我尝试再次显示所有数据,并且它再次返回 NULL,如下所示:
[{"id":27,"username":"daviduck123","password":"admin","firstName":"David","lastName":"Vincent","role":"admin","active":null,"roles":null}]
这是我的存储库 https://github.com/daviduck123/neo4j-ogm-infiniteloop
最佳答案
@RelationshipEntity表示两个节点之间的限定关系,因此在其中使用@Relationship是不正确的。
UserRole
应该看起来像
@RelationshipEntity(type = "HAS_ROLE")
public class UserRole {
@GraphId
Long id;
@StartNode
User user;
@EndNode
Role role;
Role
类中的关系方向应为 INCOMING,因为您正在定义从 User
到 的
:HAS_ROLE
关系角色
@Relationship(type = "HAS_ROLE",direction = Relationship.INCOMING)
@JsonIgnore
private Set<UserRole> userRoles;
@Relationship(type = "HAS_ROLE",direction = Relationship.INCOMING)
public Set<UserRole> getUserRoles() {
return userRoles;
}
@Relationship(type = "HAS_ROLE",direction = Relationship.INCOMING)
public void setUserRoles(Set<UserRole> userRoles) {
this.userRoles = userRoles;
}
确保访问器和修改器方法也被注释(当您具有 INCOMING 关系时,这是强制性的)。
关于Spring Data Neo4j 4 - @Fetch 更改为 findAll(int depth) 始终返回 null,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34646295/