//获取ThreadLocal
private static ThreadLocal<Page> pageLocal = new ThreadLocal<Page>();
private Page getPage() {
  return pageLocal.get();
}

BoundSql boundSql = delegate.getBoundSql();
Object parameterObject = boundSql.getParameterObject();
Page page = this.getPage(parameterObject);
private Page getPage(Object parameterObject) {
    Page page = null;
    if (parameterObject instanceof Page) {
      page = (Page) parameterObject;
    } else if (parameterObject instanceof Map) {
      for (Object val : ((Map<?, ?>) parameterObject).values()) {
        if (val instanceof Page) {
          page = (Page) val;
        }
      }
    }
    return page;
  }

@Override
public Object plugin(Object target) {
  if (target instanceof StatementHandler) {
    return Plugin.wrap(target, this);
  } else {
    return target;
  }
}