Failed to get Spring HATEOAS embedded resource object in case of @ManytoMany relationship and lookup table with extra column

Question

I can not get the built in. I use Spring boot, spring data and Spring JPA. I have 3 tables in the database

• User
• competence
• user_competency (join / composite table with optional 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 a GET using a URI, it returns an inline object to me and cannot get the real value of the attributes of the objects
GET http: // localhost: 8080 / userCompetencies

How to get attribute values ​​of a User and Competency object where userId = 8 is required Help

After implementing the proposed projection problem, it’s still not resolved, and a screenshot is shown here

Answer 1

One way is to use projections, for example, for example:

 @Projection(name = "edit" , types = Employee.class) public interface EditEmployeeProjection { String getFirstName(); String getLastName(); Set<Project> getProjects(); } 

The list of projects will be embedded in the result for http: // localhost: 8080 / api / employee / 1? Projection = edit

Predictions will be used automatically if you add excerptProjection to your repository, as described here: How to set up a complete tree structure using Spring Data REST and HATEOAS?

See here: https://shinesolutions.com/2015/04/15/spring-data-rest-and-projections/

EDITED

In this case, the projection will look like this:

 @Projection(name = "edit" , types = UserCompetency.class) public interface UserCompetencyProjection { User getUser(); Competency getCompetency(); } 

With http: // localhost: 8080 / userCompetencies? Projection = edit, you would see the desired result.

EDITED 2 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, in fact I did not notice the annotations
@RepositoryRestResource(excerptProjection = UserCompetencyProjection.class) in the UserCompetencyRepository class, now the result is as follows: I skip when it is output and put the necessary output.