title: How to ignore null and empty value when use Neo4jOperations.save() to update properties with Spring Data Neo4j?
body: <p>spring-data-neo4j : 4.1.2<br>
  neo4j:3.0.3</p>
  
  <p>Node :</p>
  
  <pre><code>Person {id:1, name:"aa", cover:"1.jpg"}
  </code></pre>
  
  <p>Class:</p>
  
  <pre><code>@NodeEntity
  public class Person{
      @GraphId
      private Long id;
      private String name;
      private String cover;
      ...
  }
  </code></pre>
  
  <p>New object:</p>
  
  <pre><code>Person p = new Person();
  p.setId(1);
  p.setName("bb");
  </code></pre>
  
  <p>then update data:</p>
  
  <pre><code>p = neo4jOperations.save(p,0);
  </code></pre>
  
  <p>or:</p>
  
  <pre><code>personRepo.save(p,0); // interface extends GraphRepository&lt;Person&gt;
  </code></pre>
  
  <p>result:</p>
  
  <pre><code>Person {id:1, name:"bb"}
  </code></pre>
  
  <p>Question: cover property has been deleted，because p.cover is null. Is there a way can ignore null value when update?</p>