Cet article présente principalement le tutoriel ActionMapping du Struts1. L'éditeur pense qu'il est plutôt bon, je vais le partager avec vous maintenant et le donner comme référence. Suivons l'éditeur et jetons un coup d'œil
Tout d'abord, le point d'arrêt est hors de la méthode processpath
<.>Cette méthode consiste à utiliser Pour intercepter des chaînes, nous allons voir aujourd'hui comment obtenir la méthode ActionMapping --- processMapping. Avant cela, parlons brièvement d'ActionMapping. Il ressort de son code source que les attributs les plus importants sont similaires à ActionMapping dans notre petite instance mvc. Ils ont tous un chemin, un type et un forwardMap. Il provient du fichier de configuration struts-config correspondant. Il s'agit de sauvegarder les informations de ce fichier de configuration en mémoire. Le code ActionMapping de la petite instance mvc spécifique est le suivant :
package com.cjq.servlet; import java.util.Map; public class ActionMapping { private String path; private Object type; private Map forwardMap; public String getPath() { return path; } public void setPath(String path) { this.path = path; } public Object getType() { return type; } public void setType(Object type) { this.type = type; } public Map getForwardMap() { return forwardMap; } public void setForwardMap(Map forwardMap) { this.forwardMap = forwardMap; } }
Entrez le code source :
/** * <p>Select the mapping used to process theselection path for this request * If no mapping can be identified, createan error response and return * <code>null</code>.</p> * * @param request The servlet request weare processing * @param response The servlet response weare creating * @param path The portion of the requestURI for selecting a mapping * * @exception IOException if an input/outputerror occurs */ protectedActionMapping processMapping(HttpServletRequestrequest, HttpServletResponse response, String path) throws IOException { // Is there a mapping for this path? ActionMapping mapping = (ActionMapping) moduleConfig.findActionConfig(path); // If a mapping is found, put it in the request and return it if (mapping != null) { request.setAttribute(Globals.MAPPING_KEY, mapping); return (mapping); } // Locate the mapping for unknown paths (if any) ActionConfig configs[] = moduleConfig.findActionConfigs(); for (int i = 0; i < configs.length; i++) { if (configs[i].getUnknown()) { mapping = (ActionMapping)configs[i]; request.setAttribute(Globals.MAPPING_KEY, mapping); return (mapping); } } // No mapping can be found to process this request String msg = getInternal().getMessage("processInvalid"); log.error(msg + " " + path); response.sendError(HttpServletResponse.SC_NOT_FOUND, msg); return null; }
ActionMapping mapping =(ActionMapping) moduleConfig.findActionConfig(path);
if (mapping != null) { request.setAttribute(Globals.MAPPING_KEY, mapping); return (mapping); }
// Locate the mapping for unknownpaths (if any) ActionConfig configs[] = moduleConfigfindActionConfigs(); for (int i = 0; i < configslength; i++) { if (configs[i].getUnknown()) { mapping = (ActionMapping)configs[i]; request.setAttribute(Globals.MAPPING_KEY, mapping); return (mapping); } } // No mapping can be found to process this request String msg = getInternal().getMessage("processInvalid"); log.error(msg + " " + path); response.sendError(HttpServletResponse.SC_NOT_FOUND, msg); return null;
/** * <p>Retrieve and return the <code>ActionForm</code> associatedwith * this mapping, creating and retaining oneif necessary. If there is no * <code>ActionForm</code> associated with this mapping,return * <code>null</code>.</p> * * @param request The servlet request weare processing * @param response The servlet response weare creating * @param mapping The mapping we are using */ protectedActionForm processActionForm(HttpServletRequestrequest, HttpServletResponse response, ActionMapping mapping) { // Create (if necessary) a form bean to use ActionForm instance = RequestUtilscreateActionForm (request, mapping, moduleConfig, servlet); if (instance == null) { return (null); } // Store the new instance in the appropriate scope if (log.isDebugEnabled()) { log.debug(" Storing ActionForm bean instance in scope '" + mapping.getScope() + "' under attribute key '" + mapping.getAttribute() + "'"); } if ("request".equals(mapping.getScope())) { request.setAttribute(mapping.getAttribute(), instance); } else { HttpSession session =requestgetSession(); session.setAttribute(mapping.getAttribute(), instance); } return (instance); }
// Create (if necessary) a formbean to use ActionForm instance = RequestUtils.createActionForm (request, mapping, moduleConfig, servlet); if (instance == null) { return (null); }
publicstaticActionForm createActionForm( HttpServletRequest request, ActionMapping mapping, ModuleConfig moduleConfig, ActionServlet servlet) { // Is there a form bean associated with this mapping? String attribute = mappinggetAttribute(); if (attribute == null) { return (null); } // Look up the form bean configuration information to use String name = mapping.getName(); FormBeanConfig config =moduleConfigfindFormBeanConfig(name); if (config == null) { log.warn("No FormBeanConfig found under '"+ name + "'"); return (null); } ActionForm instance = lookupActionForm(request,attribute, mappinggetScope()); // Can we recycle the existing form bean instance (if there is one)? try { if (instance != null && canReuseActionForm(instance,config)) { return (instance); } } catch(ClassNotFoundException e) { log.error(servlet.getInternal().getMessage("formBean",config.getType()), e); return (null); } return createActionForm(config,servlet); }
<form-beans> <form-bean name="loginForm" type=".struts.LoginActionForm"/> </form-beans>
这个标签在服务器一启动的时候就会利用digester读取这里的配置信息,并且放在FormBeanConfig类中,这样我们可以通过上面那一句话就可以把LoginForm字符串生成相应的对象。
之后调用了ActionForm instance = lookupActionForm(request,attribute, mapping.getScope());这个方法,这个方法主要是查找scope属性中有没有存在ActionForm。具体实现:
if ("request".equals(scope)){ instance = (ActionForm)request.getAttribute(attribute); } else { session = request.getSession(); instance = (ActionForm)session.getAttribute(attribute); }
这里判断scope属性值是否为request,如果是则从request中读出ActionForm,如果不是则从session中读出。程序如果是第一次执行,那么ActionForm会是为空的。因为这里的ActionForm为空,所以就进入了if判断语句中,最后通过调用return createActionForm(config, servlet);创建ActionForm并且返回。
之后processActionForm就会把返回来的ActionForm放入request或者session中。具体实现就是:
if ("request".equals(mapping.getScope())){ request.setAttribute(mapping.getAttribute(), instance); } else { HttpSession session =request.getSession(); session.setAttribute(mapping.getAttribute(), instance); }
到此为止,ActionForm就创建完成,当ActionForm创建完成之后,就要用其他的方法来往ActionForm中赋值了
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