JNDI-LDAP分页

我设法让分页工作像描述的here一样工作。问题是我需要公开一个看起来像这样的API：getUsers(pageSize, pageNumber)，这对于JNDI/LDAP执行分页的方式（每次传递给搜索方法的cookie）都不太合适。代码如下所示：JNDI-LDAP分页

private NamingEnumeration ldapPagedSearch(String filter, int pageSize, int pageNumber){ 
    InitialLdapContext ctx = getInitialContext(); 

    //TODO: get the id also, need to spec it in UI 
    // Create the search controls 
    SearchControls searchCtls = new SearchControls(); 
    searchCtls.setSearchScope(SearchControls.SUBTREE_SCOPE); 

    //keep a session 
    byte[] cookie = null; 

    //Request the paged results control 
    Control[] ctls = new Control[]{new PagedResultsControl(pageSize, true)}; 
    ctx.setRequestControls(ctls); 

    //Specify the search scope 
    NamingEnumeration results = null; 
    int currentPage = 1; 
    do { 
     results = ctx.search(getConfiguration().get(BASEDN_KEY), filter, searchCtls); 

     //we got to the right page, return this page 
     if(currentPage == pageNumber) { 
      return results; 
     } 

     // loop through this page, because we cannot get a proper cookie otherwise 
     // WARN: this could be a problem of performance 
     while (results.hasMore()) results.next(); 

     // examine the paged results control response 
     Control[] controls = ctx.getResponseControls(); 
     if (controls != null) { 
      for (Control control : controls) { 
       if (control instanceof PagedResultsResponseControl) { 
        cookie = ((PagedResultsResponseControl) control).getCookie(); 
       } 
      } 
     } 

     // pass the cookie back to the server for the next page 
     ctx.setRequestControls(new Control[]{new PagedResultsControl(pageSize, cookie, Control.CRITICAL) }); 

     //increment page 
     currentPage++; 
    } while (cookie != null); 


    ctx.close(); 

    //if we get here, means it is an empty set(consumed by the inner loop) 
    return results; 
}

看来我需要遍历所有页面以获取所需的页面。此外，我需要遍历页面上的所有条目，以便能够获取下一页。

有没有更好的方法？我担心性能问题。

来源

2011-04-21 calin014