从dubbo zookeeper注册地址提取出zookeeper地址的方法

zookeeper://localhost:2181
zookeeper://localhost:2181?client=zkclient
zookeeper://localhost:2181?backup=localhost:2182,localhost:2183
zookeeper://localhost:2181?client=zkclient&backup=localhost:2182,localhost:2183
------------结果------------
Optional[localhost:2181]
Optional[localhost:2181]
Optional[localhost:2181,localhost:2182,localhost:2182]
Optional[localhost:2181,localhost:2183,localhost:2183]

import java.util.Optional;
public class ZookeeperURL {
  public static final String PREFIX = "zookeeper://";
  public static final String BACKUP = "backup=";
  public static Optional<String> convertDubboRegistryToZookeeperURL(String dubboRegistry){
    StringBuilder zookeeperURL = new StringBuilder();
    if(dubboRegistry != null && dubboRegistry.startsWith(PREFIX)){
      dubboRegistry = dubboRegistry.substring(PREFIX.length());
      int index = dubboRegistry.indexOf("?");
      if(index > 0){
        zookeeperURL.append(dubboRegistry.substring(0, index));
        dubboRegistry = dubboRegistry.substring(index + 1);
        String[] dubboRegistries = dubboRegistry.split("&");
        for (int i = 0; i < dubboRegistries.length; i++) {
          if(dubboRegistries[i].startsWith(BACKUP)){
            String[] backups = dubboRegistries[i].substring(BACKUP.length()).split(",");
            for (int j = 0; j < backups.length; j++) {
              zookeeperURL.append(",").append(backups[i]);
            }
          }
        }
      } else {
        zookeeperURL.append(dubboRegistry);
      }
      return Optional.of(zookeeperURL.toString());
    }
    return Optional.empty();
  }
  public static void main(String[] args) {
    System.out.println(convertDubboRegistryToZookeeperURL("zookeeper://localhost:2181"));
    System.out.println(convertDubboRegistryToZookeeperURL("zookeeper://localhost:2181?client=zkclient"));
    System.out.println(convertDubboRegistryToZookeeperURL("zookeeper://localhost:2181?backup=localhost:2182,localhost:2183"));
    System.out.println(convertDubboRegistryToZookeeperURL("zookeeper://localhost:2181?client=zkclient&backup=localhost:2182,localhost:2183"));
  }
}