package org.apache.struts2.dispatcher.ng.filter;
import org.apache.struts2.StrutsStatics;
import org.apache.struts2.dispatcher.Dispatcher;
import org.apache.struts2.dispatcher.ng.PrepareOperations;
import org.apache.struts2.dispatcher.ng.ExecuteOperations;
import org.apache.struts2.dispatcher.ng.InitOperations;
import org.apache.struts2.dispatcher.mapper.ActionMapping;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* Handles both the preparation and execution phases of the Struts dispatching process. This filter is better to use
* when you don't have another filter that needs access to action context information, such as Sitemesh.
*/
public class StrutsPrepareAndExecuteFilter implements StrutsStatics, Filter {
private PrepareOperations prepare;
private ExecuteOperations execute;
//初始化過濾器
public void init(FilterConfig filterConfig) throws ServletException {
InitOperations init = new InitOperations(); //初始化輔助對象,封裝了初始化的一些操作
try {
FilterHostConfig config = new FilterHostConfig(filterConfig);
//對filterConfig進行封裝
init.initLogging(config); //通過config,初始化內部Struts的記錄
Dispatcher dispatcher = init.initDispatcher(config);
//通過config,創建並初始化dispatcher
init.initStaticContentLoader(config, dispatcher);
//通過config和dispatcher,初始化與過濾器相關的靜態內容加載器
prepare = new PrepareOperations(filterConfig.getServletContext(), dispatcher);
//通過config和dispatcher,創建request被處理前的系列操作對象
execute = new ExecuteOperations(filterConfig.getServletContext(), dispatcher);//通過config和dispatcher,創建處理request的系列操作對象
} finally {
init.cleanup(); //清空ActionContext
}
}
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
try {
prepare.createActionContext(request, response);
//創建ACTIONCONTEXT,並初始化Theadlocal
prepare.assignDispatcherToThread();
//指派dispatcher給Theadlocal
prepare.setEncodingAndLocale(request, response);
//設置request的編碼和LOCAL
request = prepare.wrapRequest(request); //封裝request
ActionMapping mapping = prepare.findActionMapping(request, response);
//查找並選擇創建ActionMapping
if (mapping == null) { //如果映射不存在
boolean handled = execute.executeStaticResourceRequest(request, response);
//試圖執行一個靜態資源的請求
if (!handled) {
chain.doFilter(request, response);
}
} else { //如果存在映射
execute.executeAction(request, response, mapping);
//執行action
}
} finally {
prepare.cleanupRequest(request); //清除request的Threadlocal
}
}
public void destroy() {
prepare.cleanupDispatcher();
}
}