刚开始用commons-jcs-2.2-bin
能够在默认和命名区域中成功存储任意复杂的对象（在使用组之前）。
在尝试使用组时，我可以看到（使用 JCSAdmin.jsp）我的键都已写入 - 但即使为我的所有键输出字符串值，例如
statesFIPSByStateCodeCache.putInGroup(state.getCode(), "stateFIPSByStateCode", state.getFipsId());
后续获取，例如
String fipsId = (String) statesFIPSByStateCodeCache.getFromGroup(stateCode, "stateFIPSByStateCode");
返回空值。
JCSAdmin.jsp 确认没有为这些键存储任何值，例如：
区域 [jurisdictions] 中键 [[GAN: groupId=[groupId=jurisdictions, stateFIPSByStateCode], attrName=WA]] 的项目
地区详情 | 所有地区
null
请帮忙！
问题似乎是我用于 GroupCacheAccess 的 JCSAdmin.jsp 版本缺乏支持（我无法找到该 JSP 作为项目可分发文件的一部分）。
我正在附加我的解决方案，该解决方案将识别并获取分组元素并使用 Gson 在项目“查看”页面上发出它们的内容以漂亮地打印对象。
<%--
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distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
--%>
<%@page import="org.apache.commons.jcs.JCS"%>
<%@page import="org.apache.commons.jcs.access.CacheAccess" %>
<%@page import="org.apache.commons.jcs.admin.CacheElementInfo" %>
<%@page import="org.apache.commons.jcs.admin.CacheRegionInfo" %>
<%@page import="java.io.Serializable" %>
<%@page import="java.util.HashMap" %>
<%@ page import="org.apache.commons.jcs.access.GroupCacheAccess" %>
<%@ page import="org.apache.commons.jcs.engine.control.group.GroupAttrName" %>
<%@ page import="org.apache.commons.jcs.engine.control.group.GroupId" %>
<%@ page import="org.apache.commons.jcs.engine.behavior.ICacheElement" %>
<%@ page import="org.springframework.util.StringUtils" %>
<%@ page import="com.google.gson.Gson" %>
<%@ page import="com.google.gson.GsonBuilder" %>
<jsp:useBean id="jcsBean" scope="request" class="org.apache.commons.jcs.admin.JCSAdminBean" />
<html>
<head>
<SCRIPT LANGUAGE="Javascript">
function decision( message, url )
{
if( confirm(message) )
{
location.href = url;
}
}
</SCRIPT>
<title> JCS Admin Servlet </title>
</head>
<body>
<%
String CACHE_NAME_PARAM = "cacheName";
String ACTION_PARAM = "action";
String CLEAR_ALL_REGIONS_ACTION = "clearAllRegions";
String CLEAR_REGION_ACTION = "clearRegion";
String REMOVE_ACTION = "remove";
String DETAIL_ACTION = "detail";
String REGION_SUMMARY_ACTION = "regionSummary";
String ITEM_ACTION = "item";
String KEY_PARAM = "key";
String SILENT_PARAM = "silent";
String DEFAULT_TEMPLATE_NAME = "DEFAULT";
String REGION_DETAIL_TEMPLATE_NAME = "DETAIL";
String ITEM_TEMPLATE_NAME = "ITEM";
String REGION_SUMMARY_TEMPLATE_NAME = "SUMMARY";
String templateName = DEFAULT_TEMPLATE_NAME;
HashMap<String, Object> context = new HashMap<String, Object>();
// Get cacheName for actions from request (might be null)
String cacheName = request.getParameter( CACHE_NAME_PARAM );
if ( cacheName != null )
{
cacheName = cacheName.trim();
}
// If an action was provided, handle it
String action = request.getParameter( ACTION_PARAM );
if ( action != null )
{
if ( action.equals( CLEAR_ALL_REGIONS_ACTION ) )
{
jcsBean.clearAllRegions();
}
else if ( action.equals( CLEAR_REGION_ACTION ) )
{
if ( cacheName == null )
{
// Not Allowed
}
else
{
jcsBean.clearRegion( cacheName );
}
}
else if ( action.equals( REMOVE_ACTION ) )
{
String[] keys = request.getParameterValues( KEY_PARAM );
for ( int i = 0; i < keys.length; i++ )
{
jcsBean.removeItem( cacheName, keys[ i ] );
}
templateName = REGION_DETAIL_TEMPLATE_NAME;
}
else if ( action.equals( DETAIL_ACTION ) )
{
templateName = REGION_DETAIL_TEMPLATE_NAME;
}
else if ( action.equals( ITEM_ACTION ) )
{
templateName = ITEM_TEMPLATE_NAME;
}
else if ( action.equals( REGION_SUMMARY_ACTION ) )
{
templateName = REGION_SUMMARY_TEMPLATE_NAME;
}
}
if ( request.getParameter( SILENT_PARAM ) != null )
{
// If silent parameter was passed, no output should be produced.
//return null;
}
else
{
// Populate the context based on the template
if ( templateName == REGION_DETAIL_TEMPLATE_NAME )
{
//context.put( "cacheName", cacheName );
context.put( "elementInfoRecords", jcsBean.buildElementInfo( cacheName ) );
}
else if ( templateName == DEFAULT_TEMPLATE_NAME )
{
context.put( "cacheInfoRecords", jcsBean.buildCacheInfo() );
}
}
///////////////////////////////////////////////////////////////////////////////////
//handle display
String elemToString="";
Gson gson = new GsonBuilder().setPrettyPrinting().create();
if ( templateName == ITEM_TEMPLATE_NAME )
{
String key = request.getParameter( KEY_PARAM );
if ( key != null )
{
key = key.trim();
}
org.apache.commons.jcs.engine.behavior.ICacheElement<?, ?> element;
if (key.startsWith("[")) {
// Need to parse the key for GroupCacheAccess
// [[GAN: groupId=[groupId=jurisdictions, states], attrName=01]]
int end = key.indexOf("]");
int start = key.indexOf(",")+1;
String groupName = key.substring(start, end).trim();
start = key.indexOf("e=")+2;
end = key.indexOf("]", start);
String keyValue = key.substring(start, end);
GroupCacheAccess groupCacheAccess = JCS.getGroupCacheInstance(cacheName);
Object o = groupCacheAccess.getFromGroup(keyValue, groupName);
String className = o.toString(); // should return an object label
className = className.substring(0, className.indexOf("@"));
elemToString = "<div style='font-weight: bold;'>" + className + "</div><div style='margin-top: 10px;'>" + gson.toJson(o) + "</div>";
} else {
CacheAccess<Serializable, Serializable> cache = JCS.getInstance( cacheName );
element = cache.getCacheElement( key );
elemToString = element.getVal().toString();
}
%>
<h1> Item for key [<%=key%>] in region [<%=cacheName%>] </h1>
<a href="JCSAdmin.jsp?action=detail&cacheName=<%=cacheName%>">Region Detail</a>
| <a href="JCSAdmin.jsp">All Regions</a>
<pre>
<%=elemToString %>
</pre>
<%
}
else if ( templateName == REGION_SUMMARY_TEMPLATE_NAME )
{
%>
<h1> Summary for region [<%=cacheName%>] </h1>
<a href="JCSAdmin.jsp">All Regions</a>
<%
CacheAccess<?, ?> cache = JCS.getInstance( cacheName );
String stats = cache.getStats();
%>
<br>
<b> Stats for region [<%=cacheName%>] </b>
<pre>
<%=stats%>
</pre>
<%
}
else if ( templateName == REGION_DETAIL_TEMPLATE_NAME )
{
%>
<h1> Detail for region [<%=cacheName%>] </h1>
<a href="JCSAdmin.jsp">All Regions</a>
<table border="1" cellpadding="5" >
<tr>
<th> Key </th>
<th> Eternal? </th>
<th> Create time </th>
<th> Max Life (s) </th>
<th> Till Expiration (s) </th>
</tr>
<%
CacheElementInfo[] list = (CacheElementInfo[]) context.get( "elementInfoRecords" );
for (CacheElementInfo element : list)
{
%>
<tr>
<td> <%=element.getKey()%> </td>
<td> <%=element.isEternal()%> </td>
<td> <%=element.getCreateTime()%> </td>
<td> <%=element.getMaxLifeSeconds()%> </td>
<td> <%=element.getExpiresInSeconds()%> </td>
<td>
<a href="JCSAdmin.jsp?action=item&cacheName=<%=cacheName%>&key=<%=element.getKey()%>"> View </a>
| <a href="JCSAdmin.jsp?action=remove&cacheName=<%=cacheName%>&key=<%=element.getKey()%>"> Remove </a>
</td>
</tr>
<%
}
CacheAccess<?, ?> cache = JCS.getInstance( cacheName );
String stats = cache.getStats();
%>
</table>
<br>
<b> Stats for region [<%=cacheName%>] </b>
<pre>
<%=stats%>
</pre>
<%
}
else
{
%>
<h1> Cache Regions </h1>
<p>
These are the regions which are currently defined in the cache. 'Items' and
'Bytes' refer to the elements currently in memory (not spooled). You can clear
all items for a region by selecting 'Remove all' next to the desired region
below. You can also <a href="javascript:decision('Clicking OK will clear all the data from all regions!','JCSAdmin.jsp?action=clearAllRegions')">Clear all regions</a>
which empties the entire cache.
</p>
<p>
<form action="JCSAdmin.jsp">
<input type="hidden" name="action" value="item">
Retrieve (key) <input type="text" name="key">
(region) <select name="cacheName">
<%
CacheRegionInfo[] listSelect = (CacheRegionInfo[]) context.get( "cacheInfoRecords" );
for (CacheRegionInfo record : listSelect)
{
%>
<option value="<%=record.getCacheName()%>"><%=record.getCacheName()%></option>
<%
}
%>
</select>
<input type="submit">
</form>
</p>
<table border="1" cellpadding="5" >
<tr>
<th> Cache Name </th>
<th> Items </th>
<th> Bytes </th>
<th> Status </th>
<th> Memory Hits </th>
<th> Aux Hits </th>
<th> Not Found Misses </th>
<th> Expired Misses </th>
</tr>
<%
CacheRegionInfo[] list = (CacheRegionInfo[]) context.get( "cacheInfoRecords" );
for (CacheRegionInfo record : listSelect)
{
%>
<tr>
<td> <%=record.getCacheName()%> </td>
<td> <%=record.getCacheSize()%> </td>
<td> <%=record.getByteCount()%> </td>
<td> <%=record.getCacheStatus()%> </td>
<td> <%=record.getHitCountRam()%> </td>
<td> <%=record.getHitCountAux()%> </td>
<td> <%=record.getMissCountNotFound()%> </td>
<td> <%=record.getMissCountExpired()%> </td>
<td>
<a href="JCSAdmin.jsp?action=regionSummary&cacheName=<%=record.getCacheName()%>"> Summary </a>
| <a href="JCSAdmin.jsp?action=detail&cacheName=<%=record.getCacheName()%>"> Detail </a>
| <a href="javascript:decision('Clicking OK will remove all the data from the region [<%=record.getCacheName()%>]!','JCSAdmin.jsp?action=clearRegion&cacheName=<%=record.getCacheName()%>')"> Clear </a>
</td>
</tr>
<%
}
%>
</table>
<%
}
%>
</body>
</html>