java使用Swagger文档报错“java.lang.NullPointerException:null”

 ERROR s.d.s.web.plugins.DocumentationPluginsBootstrapper:98 - Unable to scan documentation context default
java.lang.NullPointerException: null
	at springfox.documentation.schema.Example.equals(Example.java:131)
	at java.util.Objects.equals(Objects.java:59)
	at springfox.documentation.service.RequestParameter.equals(RequestParameter.java:132)
	at java.util.HashMap.putVal(HashMap.java:634)

@Override
public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    if (!o.toString().equals("")){
      Example example = (Example) o;
      return id.equals(example.id) &&
              Objects.equals(summary, example.summary) &&
              Objects.equals(description, example.description) &&
              value.equals(example.value) &&
              externalValue.equals(example.externalValue) &&
              mediaType.equals(example.mediaType) &&
              extensions.equals(example.extensions);
    } else {
      return false;
    }
  }