java - How to join three entities in one table using spring jpa? -

i trying join 3 entities (table) using spring-jpa 1 table using many-to-many relationship.

three classes :

1] user

2] resource

3] privilege

and want combine these 3 entities 1 user_resource_privilege table

user entity

package com.****.acl.domain; import java.util.arraylist; import java.util.collection; import javax.persistence.column; import javax.persistence.entity; import javax.persistence.generatedvalue; import javax.persistence.id; import javax.persistence.manytomany;  import org.hibernate.annotations.genericgenerator;  import javax.persistence.*;  @entity public class user {  @id @generatedvalue(generator="system-uuid") @genericgenerator(name="system-uuid", strategy = "uuid") @column(name="user_id", nullable=false, length=40) private string userid;  @column(name="user_name", nullable=false, length=45) private string username;  @column(name="first_name", nullable=true, length=45) private string firstname;  @column(name="last_name", nullable=true, length=45) private string lastname;  @column(name="email", nullable=true, length=50) private string email;  public user(){  }  public user(string username, string firstname, string lastname, string email) {     this.username = username;     this.firstname = firstname;     this.lastname = lastname;     this.email = email;        }   getter , setters ....... } 

resource entity

import java.util.arraylist; import java.util.collection; import javax.persistence.*; import org.hibernate.annotations.genericgenerator;  @entity public class resource {  @id @generatedvalue(generator="system-uuid") @genericgenerator(name="system-uuid", strategy = "uuid") @column(name="resource_id", nullable=false, length=40) private string resourceid;  @column(name="resource_name", nullable=false, length=45) private string name;  @column(name="resource_type", nullable=false, length=45) private string type;  public resource(){  }  public resource(string name, string type) {     this.name = name;     this.type = type; }  getter , setter ...... } 

privilege entity

import java.util.arraylist; import java.util.collection; import javax.persistence.*; import org.hibernate.annotations.genericgenerator;  @entity public class privilege {  @id @generatedvalue(generator="system-uuid") @genericgenerator(name="system-uuid", strategy = "uuid") @column(name="privilege_id", nullable=false, length=40) private string privilegeid;  @column(name="resource_name", nullable=false, length=45) private string name;  @column(name="resource_description", nullable=true, length=45) private string description;  public privilege(){  }  getters , setters .... } 

now want create 1 table joining 3 entities described above.

the join in er diagram:

can please me in joining these 3 tables using many-to-many relationship , let me know how achieve using spring-jpa , rest ? great if please explain how insert data in "user_resource_privilege" table using rest/curl command ?

what make embeddable id , wrap class. can afterwards expand wrapper class hold other fields.

java geeks example of embedded id

you

@embeddable public class embeddedidclass implements serializable {   private string userid;   private string resourceid;   private string privilegeid;  // constructors, getters , setters, equals, etc }  @entity public class wrapper {   @embeddedid   private embeddedidclass id;  // constructors, etc } 

instead of using strings in example, should use complete objects , let hibernate (or it) it's stuff. should take id's database , it's magic itself.

edit: wanting insert id's values, keeping relationships this

@entity public class wrapper {   @id   private string id;   private user user;   private resource resource;   private privilege privilege;   // constructors   public wrapper(final user user, final resource resource, final privilege privilege) {     this.user = user;     this.resource = resource;     this.privilege = privilege;   } }