使用public String中的public static（非静态）

Question

我需要您帮忙在脚本上使用变量non static中的set variable static
  "GetIP_Public = this.conn_public;"

public class GlobalClass extends Application {

    public String conn_public;
    public static GlobalClass GetIP_Public;


    public static GlobalClass GetIP_Public(){
      GetIP_Public = this.conn_public;
     return GetIP_Public;
    }

    private static class GetIP_Public {

    }

    public String getConn_public() {
        return conn_public;
    }

    public void setConn_public(String conn_public) {
        this.conn_public = conn_public;

    }