Unable to retrieve Spring HATEOAS embedded resource object in case of #ManytoMany relationship and lookup table with extra column - spring-boot

Question

I am unable to retrieve embedded .I am using Spring boot ,spring data rest and spring JPA. I have 3 tables in data base
user
competency
user_competency (join/composite table with extra column)
User
#Entity
#Table(name = "\"user\"", schema = "public")
#JsonIdentityInfo(
generator = ObjectIdGenerators.IntSequenceGenerator.class,
property = "userId")
public class User implements java.io.Serializable {
private Long userId;
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "user_id", unique = true, nullable = false)
public Long getUserId() {
return this.userId;
}
public void setUserId(Long userId) {
this.userId = userId;
}
private Set<UserCompetency> userCompetencies = new HashSet<UserCompetency>(0);
#OneToMany(fetch = FetchType.EAGER,cascade = {CascadeType.ALL}, mappedBy = "user")
public Set<UserCompetency> getUserCompetencies() {
return this.userCompetencies;
}
public void setUserCompetencies(Set<UserCompetency> userCompetencies) {
this.userCompetencies = userCompetencies;
}
}
**Competency**
#Entity
#Table(name = "competency", schema = "public")
#JsonIdentityInfo(
generator = ObjectIdGenerators.IntSequenceGenerator.class,
property = "competencyId")
public class Competency implements java.io.Serializable {
private Long competencyId;
private Set<UserCompetency> userCompetencies = new HashSet<UserCompetency>(0);
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "competency_id", unique = true, nullable = false)
public Long getCompetencyId() {
return this.competencyId;
}
public void setCompetencyId(Long competencyId) {
this.competencyId = competencyId;
}
#OneToMany(fetch = FetchType.LAZY, mappedBy = "competency")
public Set<UserCompetency> getUserCompetencies() {
return this.userCompetencies;
}
public void setUserCompetencies(Set<UserCompetency> userCompetencies) {
this.userCompetencies = userCompetencies;
}
}
UserCompetency
#Entity
#Table(name = "user_competency", schema = "public")
#JsonIdentityInfo(
generator =ObjectIdGenerators.IntSequenceGenerator.class,
property = "id")
public class UserCompetency implements java.io.Serializable {
private UserCompetencyId id;
private Level level;
private User user;
private Competency competency;
#EmbeddedId
#AttributeOverrides({
#AttributeOverride(name = "competencyId", column = #Column(name = "competency_id", nullable = false)),
#AttributeOverride(name = "userId", column = #Column(name = "user_id", nullable = false)) })
public UserCompetencyId getId() {
return this.id;
}
public void setId(UserCompetencyId id) {
this.id = id;
}
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "level_id")
public Level getLevel() {
return this.level;
}
public void setLevel(Level level) {
this.level = level;
}
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "user_id", nullable = false, insertable = false, updatable = false)
public User getUser() {
return this.user;
}
public void setUser(User user) {
this.user = user;
}
#ManyToOne(fetch = FetchType.EAGER,cascade=CascadeType.ALL)
#JoinColumn(name = "competency_id", nullable = false, insertable = false, updatable = false)
public Competency getCompetency() {
return this.competency;
}
public void setCompetency(Competency competency) {
this.competency = competency;
}
}
UserCompetencyId
#Embeddable
public class UserCompetencyId implements java.io.Serializable {
private Long competencyId;
private Long userId;
public UserCompetencyId() {
}
public UserCompetencyId(Long competencyId, Long userId) {
this.competencyId = competencyId;
this.userId = userId;
}
#Column(name = "competency_id", nullable = false)
public Long getCompetencyId() {
return this.competencyId;
}
public void setCompetencyId(Long competencyId) {
this.competencyId = competencyId;
}
#Column(name = "user_id", nullable = false)
public Long getUserId() {
return this.userId;
}
public void setUserId(Long userId) {
this.userId = userId;
}
public boolean equals(Object other) {
if ((this == other))
return true;
if ((other == null))
return false;
if (!(other instanceof UserCompetencyId))
return false;
UserCompetencyId castOther = (UserCompetencyId) other;
return (this.getCompetencyId() == castOther.getCompetencyId()) && (this.getUserId() == castOther.getUserId());
}
}
UserCompetencyRepository
public interface UserCompetencyRepository extends JpaRepository<UserCompetency, UserCompetencyId> {
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>Demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<name>Demo</name>
<description>Demo api </description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-rest-hal-browser</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-hateoas</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.restdocs</groupId>
<artifactId>spring-restdocs-mockmvc</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-rest-webmvc</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
and I want to perform GET using URI,it return me embedded object and cannot get real value of objects attributes
GET http://localhost:8080/userCompetencies
How Can I get attribute values of User and Competency object where userId=8 Help is required
After implementing suggested Projection Issue still not resolved and here is screen shot

Answer 1

One way would be to use projections like for example:
#Projection(name = "edit" , types = Employee.class)
public interface EditEmployeeProjection {
String getFirstName();
String getLastName();
Set<Project> getProjects();
}
With this the project list will be embedded in the result for http://localhost:8080/api/employee/1?projection=edit
Projections would be used automatically if you add excerptProjection to you repository like described here: How to expose a complete tree structure with Spring Data REST and HATEOAS?
See for example here: https://shinesolutions.com/2015/04/15/spring-data-rest-and-projections/
EDITED
In you case a projection would look like:
#Projection(name = "edit" , types = UserCompetency.class)
public interface UserCompetencyProjection {
User getUser();
Competency getCompetency();
}
With http://localhost:8080/userCompetencies?projection=edit you would then see wanted result.
EDITED 2
The code I used:
Competency.class
#Entity
#Table(name = "competency", schema = "public")
#JsonIdentityInfo(
generator = ObjectIdGenerators.IntSequenceGenerator.class,
property = "competencyId")
public class Competency implements java.io.Serializable {
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "competency_id", unique = true, nullable = false)
private Long competencyId;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "competency")
private List<UserCompetency> userCompetencies = new ArrayList<>();
UserCompetency.class
#Entity
#Table(name = "user_competency", schema = "public")
#JsonIdentityInfo(
generator = ObjectIdGenerators.IntSequenceGenerator.class,
property = "id")
public class UserCompetency implements java.io.Serializable {
#EmbeddedId
#AttributeOverrides({
#AttributeOverride(name = "competencyId", column = #Column(name = "competency_id", nullable = false)),
#AttributeOverride(name = "userId", column = #Column(name = "user_id", nullable = false)) })
private UserCompetencyId id;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "user_id", nullable = false, insertable = false, updatable = false)
private User user;
#ManyToOne(fetch = FetchType.EAGER,cascade = CascadeType.ALL)
#JoinColumn(name = "competency_id", nullable = false, insertable = false, updatable = false)
private Competency competency;
UserCompetencyId.class
#Embeddable
public class UserCompetencyId implements java.io.Serializable {
#Column(name = "competency_id", nullable = false)
private Long competencyId;
#Column(name = "user_id", nullable = false)
private Long userId;
UserCompetencyRepository.class
#RepositoryRestResource(excerptProjection = UserCompetencyProjection.class)
public interface UserCompetencyRepository extends JpaRepository<UserCompetency, UserCompetencyId> {
After Implementing This ,In my case its not working to show desired jason [![enter image description here][2]][2]

Answer 2

It worked out ,actually i was missing annotation of #RepositoryRestResource(excerptProjection = UserCompetencyProjection.class)
on UserCompetencyRepository class now the output look like this I am skipping as it is output , and putting necessary output.