struts 中的正常操作 class 与此模式有何区别？
What the difference between a normal action class in struts and this patern?
我正在开发一个项目，该项目使用两个动作 class，一个从另一个扩展，并且具有相同的方法实现（因此没有覆盖）。
一个动作 class 和 returns 一个 ActionForward 与 execute 方法有什么区别：
package com.mkyong.common.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.mkyong.common.form.HelloWorldForm;
public class HelloWorldAction extends Action{
public ActionForward execute(ActionMapping mapping,ActionForm form,
HttpServletRequest request,HttpServletResponse response)
throws Exception {
HelloWorldForm helloWorldForm = (HelloWorldForm) form;
helloWorldForm.setMessage("Hello World! Struts");
return mapping.findForward("success");
}
}
第二个逻辑：
SuggestCommentAction.java :
package org.dlese.dpc.suggest.action;
import org.dlese.dpc.suggest.SuggestUtils;
import org.dlese.dpc.suggest.comment.*;
import org.dlese.dpc.suggest.resource.urlcheck.*;
import org.dlese.dpc.suggest.action.form.SuggestCommentForm;
import org.dlese.dpc.xml.schema.*;
import org.dlese.dpc.xml.*;
import org.dlese.dpc.util.strings.FindAndReplace;
import org.dlese.dpc.vocab.MetadataVocab;
import java.util.*;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.util.MessageResources;
/**
* * Action controller for the Suggest a Comment servlet.
* @version $Id: SuggestCommentAction.java,
*/
public final class SuggestCommentAction extends SuggestAction {
private static boolean debug = true;
private SuggestCommentHelper suggestHelper = null;
/**
* Gets the SuggestCommentHelper attribute of the SuggestCommentAction
* object
*
* @return The SuggestCommentHelper value
* @exception ServletException NOT YET DOCUMENTED
*/
protected SuggestCommentHelper getSuggestHelper () throws ServletException {
if (suggestHelper == null) {
try {
suggestHelper = (SuggestCommentHelper) servlet.getServletContext().getAttribute("SuggestCommentHelper");
if (suggestHelper == null)
throw new Exception ();
} catch (Throwable t) {
throw new ServletException ("SuggestCommentHelper is not initialized");
}
}
return suggestHelper;
}
protected ActionForward initializeSuggestor(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws ServletException {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String id = request.getParameter("id");
if (id == null || id.trim().length() == 0) {
errors.add("error",
new ActionError("comment.id.required"));
saveErrors(request, errors);
return mapping.findForward("home");
}
scf.clear();
scf.setPopup("p".equals( request.getParameter("view")));
scf.setItemID(id);
// ensure the provided record id (itemID) corresponds to an existing record
String itemTitle = null;
String itemURL = null;
try {
Map itemRecordProps = this.getSuggestHelper().getItemRecordProps(id);
scf.setItemURL ((String)itemRecordProps.get ("url"));
scf.setItemTitle((String)itemRecordProps.get ("title"));
} catch (Exception e) {
errors.add("error",
new ActionError("comment.resource.not.found", id));
saveErrors(request, errors);
return mapping.findForward("home");
}
saveMessages(request, errors);
return mapping.findForward("form");
}
// ------------ Command Handlers ----------------------------------
protected ActionForward handleOtherCommands(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String command = request.getParameter("command");
prtln("command: " + command);
throw new ServletException("unsupported command: " + command);
}
protected ActionForward handleEditCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {
SuggestCommentForm scf = (SuggestCommentForm) form;
if (scf.getItemID() == null || scf.getItemID().length() == 0 ) {
prtln("can't edit without a id ... bailing");
return handleStaleData(mapping, form, request);
}
return mapping.findForward("form");
}
protected ActionForward handleCancelCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
scf.clear();
scf.setItemID("");
errors.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("comment.cancel"));
saveMessages(request, errors);
return mapping.findForward("home");
}
protected ActionForward handleDoneCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
// make sure there is a value for URL. If the user has previously "cancelled" and then
// used the back buttons to return to an old form that *looks* like it holds data, but really
// the data has been lost to the app upon cancellation
if (scf.getItemID() == null || scf.getItemID().length() == 0) {
prtln("can't get to done without a itemID ... bailing");
return handleStaleData(mapping, form, request);
}
// Validate
errors = validateSuggestForm(form, mapping, request);
// report errors
if (!errors.isEmpty()) {
saveErrors(request, errors);
return mapping.findForward("form");
}
return mapping.findForward("confirm");
}
protected ActionForward handleSubmitCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
// make sure there is a value for URL. If the user has previously "cancelled" and then
// used the back buttons to return to an old form that *looks* like it holds data, but really
// the data has been lost to the app upon cancellation
if (scf.getItemID() == null || scf.getItemID().length() == 0) {
prtln("can't submit without a url ... bailing");
return handleStaleData(mapping, form, request);
}
ActionMessages actionMessages = new ActionMessages();
CommentRecord rec = null;
try {
rec = createRecord(scf);
} catch (Exception e) {
System.out.println("createRecord() failed to set values\n" + e);
e.printStackTrace();
}
// putRecord to DCS
String newId = null;
try {
newId = this.getSuggestHelper().putRecordToDCS(rec);
} catch (Throwable e) {
prtln("putRecord error: " + e.getMessage());
}
boolean notificationSent = false;
try {
new CommentEmailer(newId, this.getSuggestHelper()).sendNotification(scf);
} catch (Exception e) {
prtlnErr ("Email error: " + e.getMessage());
}
if (!notificationSent) {
prtln("Notification NOT sent!");
}
else {
prtln("Notification sent");
}
scf.clear();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("comment.confirmation"));
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
/**
* The required fields for suggest-a-url are: url, nameFirst, nameLast,
* emailPrimary, instName
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected ActionErrors validateSuggestForm(ActionForm form,
ActionMapping mapping,
HttpServletRequest request) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String description = scf.getDescription();
String role = scf.getRole();
String share = scf.getShare();
String nameFirst = scf.getNameFirst();
String nameLast = scf.getNameLast();
String email = scf.getEmail();
String instName = scf.getInstName();
Boolean coppa = scf.getCoppa();
if ((description == null) || (description.trim().equals(""))) {
errors.add("description", new ActionError("field.required", "Comment"));
}
if ((role == null) || (role.trim().equals(""))) {
errors.add("role", new ActionError("field.required", "Role"));
}
if ((share == null) || (share.trim().equals(""))) {
errors.add("share", new ActionError("this.field.required", "Share"));
}
if ((nameFirst == null) || (nameFirst.trim().equals(""))) {
errors.add("nameFirst", new ActionError("field.required", "First Name"));
}
if ((nameLast == null) || (nameLast.trim().equals(""))) {
errors.add("nameLast", new ActionError("field.required", "Last Name"));
}
if (!coppa) {
errors.add("coppa", new ActionError("this.field.required"));
}
if ((instName == null) || (instName.trim().equals(""))) {
errors.add("instName", new ActionError("field.required.an", "Institution or Affiliation"));;
}
if ((email == null) || (email.trim().equals(""))) {
errors.add("email", new ActionError("field.required.an", "Email Address"));
}
else {
try {
SuggestUtils.validateEmail (email);
} catch (Exception e) {
errors.add("email",
new ActionError("generic.error", e.getMessage()));
}
}
return errors;
}
/**
* Update the SuggestionRecord (managed by SuggestCommentHelper) with values
* from the form bean.<P>
*
* @param form NOT YET DOCUMENTED
* @exception Exception Description of the Exception
*/
protected CommentRecord createRecord(ActionForm form)
throws Exception {
SuggestCommentForm scf = (SuggestCommentForm) form;
CommentRecord rec = this.getSuggestHelper().newRecord();
if (rec == null) {
throw new Exception("createRecord could not get a record from SuggestCommentForm");
}
rec.setTitle("Comment on " + scf.getItemTitle());
rec.setItemID(scf.getItemID());
rec.setDescription(scf.getDescription());
rec.setRole(scf.getRole());
rec.setShare(scf.getShare());
rec.setNameFirst(scf.getNameFirst());
rec.setNameLast(scf.getNameLast());
rec.setEmail(scf.getEmail());
rec.setInstName(scf.getInstName());
rec.setCreationDate(SuggestUtils.getBriefDate());
return rec;
}
/**
* Sets the debug attribute of the SuggestCommentAction class
*
* @param db The new debug value
*/
public static void setDebug(boolean db) {
debug = db;
}
/**
* Print a line to standard out.
*/
private static void prtln(String s) {
if (debug) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestCommentAction");
}
}
private static void prtlnErr(String s) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestCommentAction");
}
}
SuggestAction.java
package org.dlese.dpc.suggest.action;
import org.dlese.dpc.suggest.*;
import org.dlese.dpc.suggest.action.form.SuggestForm;
import org.dlese.dpc.xml.schema.*;
import org.dlese.dpc.xml.*;
import org.dlese.dpc.vocab.MetadataVocab;
import java.util.*;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.util.MessageResources;
/**
* Abstract controller for a Suggestor Client. Implements the following flow of
* control:
* <ol>
* <li> Presents form for user input
* <li> Validates input. if there are errors returns user to form, otherwise
* presents confirmation page.
* <li> User can elect to re-edit the form, or "submit" it.
* <li> confirmation page is displayed upon submission
* </ol>
*/
public abstract class SuggestAction extends Action {
private static boolean debug = true;
/**
* Gets the suggestHelper attribute of the SuggestAction object
*
* @return The suggestHelper value
* @exception ServletException NOT YET DOCUMENTED
*/
protected abstract SuggestHelper getSuggestHelper() throws ServletException;
/**
* Gets the schemaHelper attribute of the SuggestAction object
*
* @return The schemaHelper value
*/
protected SchemaHelper getSchemaHelper() {
try {
return getSuggestHelper().getSchemaHelper();
} catch (Exception e) {}
return null;
}
// --------------------------------------------------------- Public Methods
/**
* Processes the specified HTTP request and creates the corresponding HTTP
* response by forwarding to a JSP that will create it. Returns an {@link
* org.apache.struts.action.ActionForward} instance that maps to the Struts
* forwarding name "xxx.xxx," which must be configured in struts-config.xml to
* forward to the JSP page that will handle the request.
*
* @param mapping Description of the Parameter
* @param form Description of the Parameter
* @param request Description of the Parameter
* @param response Description of the Parameter
* @return Description of the Return Value
* @exception IOException Description of the Exception
* @exception ServletException Description of the Exception
*/
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
/*
Design note:
Only one instance of this class gets created for the app and shared by
all threads. To be thread-safe, use only local variables, not instance
variables (the JVM will handle these properly using the stack). Pass
all variables via method signatures rather than instance vars.
*/
SuggestForm sform = (SuggestForm) form;
SchemaHelper schemaHelper = getSchemaHelper();
sform.setSchemaHelper(schemaHelper);
MetadataVocab vocab = (MetadataVocab) servlet.getServletContext().getAttribute("MetadataVocab");
sform.setVocab(vocab);
ActionErrors errors = new ActionErrors();
ActionMessages actionMessages = new ActionMessages();
// Query Args
String command = request.getParameter("command");
// prtln("\ncommand: " + command + "\n");
org.dlese.dpc.schemedit.SchemEditUtils.showRequestParameters(request);
// HANDLE COMMAND
try {
if (command == null) {
// return handleCancelCommand(mapping, form, request, response);
return initializeSuggestor(mapping, form, request, response);
}
// NEW - present simple form to get (and validate) URL
if (command.equalsIgnoreCase("cancel")) {
return handleCancelCommand(mapping, form, request, response);
}
// EDIT - read record and present form for editing
if (command.equalsIgnoreCase("edit")) {
return handleEditCommand(mapping, form, request, response);
}
// SUBMIT - user has confirmed data - now write it to disk
// data is valid at this point and the user has hit the submit button
if (command.equalsIgnoreCase("submit")) {
return handleSubmitCommand(mapping, form, request, response);
}
// DONE - validate data and present confirmation page to user
if (command.equalsIgnoreCase("done")) {
return handleDoneCommand(mapping, form, request, response);
}
return handleOtherCommands(mapping, form, request, response);
} catch (Exception e) {
prtlnErr("ERROR: " + e.getMessage());
e.printStackTrace();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("generic.error", "Server Error: " + e.getMessage()));
} catch (Throwable t) {
prtlnErr("UNKNOWN ERROR: " + t.getMessage());
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("generic.error", "Unknown Server Error"));
}
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
protected abstract ActionForward initializeSuggestor(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException;
/**
* Hook for subclasses to handle commands that are outside the ones defined in
* this class.
*/
protected ActionForward handleOtherCommands(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException {
String command = request.getParameter("command");
prtln("command: " + command);
throw new ServletException("unsupported command: " + command);
}
/**
* Populate SuggestionForm, and forward user to edit-form.
* @exception Exception if SuggestionForm cannot be populated with required
* info.
*/
protected abstract ActionForward handleEditCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception;
protected abstract ActionForward handleCancelCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Validate information supplied by user, return to edit form if there are
* errors, or display confirmation page if there are no errors.
*/
protected abstract ActionForward handleDoneCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Attempt to write the suggestion to a DCS instance, forward user to
* confirmation page.
*/
protected abstract ActionForward handleSubmitCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Return user to suggestor front page and show message explaining that they
* were apparently trying to edit or submit data from a cancelled form
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected ActionForward handleStaleData(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request) {
SuggestForm sForm = (SuggestForm) form;
sForm.clear();
prtln("handleStaleData");
ActionMessages actionMessages = new ActionMessages();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("stale.data"));
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
/**
* The required fields for suggest-a-url are: url, nameFirst, nameLast,
* emailPrimary, instName
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected abstract ActionErrors validateSuggestForm(ActionForm form,
ActionMapping mapping,
HttpServletRequest request);
/**
* Update the SuggestionRecord (managed by SuggestResourceHelper) with values
* from the form bean
*
* @param form NOT YET DOCUMENTED
* @exception Exception Description of the Exception
*/
protected abstract SuggestionRecord createRecord(ActionForm form) throws Exception;
/**
* Sets the debug attribute of the SuggestAction class
*
* @param db The new debug value
*/
public static void setDebug(boolean db) {
debug = db;
}
/**
* Print a line to standard out.
*
* @param s The String to print.
*/
private static void prtln(String s) {
if (debug) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestAction");
}
}
private static void prtlnErr(String s) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestAction");
}
}
抽象基础 class 是一个 classic 命令模式处理程序：
String command = request.getParameter("command");
这决定了执行哪个命令运行。因此，无论是在表单还是 URL 中，通常应该 always/will 是一个 command 来确定流程的其余部分。
默认命令是 cancel、edit、submit 和 done，但实施 classes 可能会通过 handleOtherCommands 函数，在默认实现中抛出错误。
*请注意，在 SuggestCommentAction 中提供了一个无用的实现，该实现执行基础 class 已经执行的操作。
每个实现都应该实现 initializeSuggestor 功能。如果提供 none，此处的实现会提前检查 ID 和 returns。剩下的就是家务；确定它是否显示在弹出窗口中（view 参数），尝试查找记录，并 returns 适当的转发。
edit、cancel、done 和 submit、abstract 在基础 class 中，或多或少做你想做的期望：他们执行数据库操作并将视图路由到为 SuggestCommentAction.
定义的任何内容
每个实现都应提供处理特定表单验证要求的验证函数。
每个实现都应提供一个 createRecord 函数返回 SuggestionRecord 的实现，在本例中为 CommentRecord。这在很大程度上只是将表单数据编组到域对象中。 （请注意，有些库会自动执行此操作，但如果正在进行大量转换，则并不总是合适的。）
TL;DR:
这是一种为不同域对象委派基本 CRUD 操作的机制，其中每个域对象将由 SuggestAction.
的实现表示
这很可能（很有可能）是相当旧的代码：它打破了我认为是很多功能边界的东西，例如，它依赖于 Struts 1-specific functionality in each执行。在 S1 时代，这相当普遍，因为 S1 的架构和预期使用方式。
我正在开发一个项目，该项目使用两个动作 class，一个从另一个扩展，并且具有相同的方法实现（因此没有覆盖）。 一个动作 class 和 returns 一个 ActionForward 与 execute 方法有什么区别：
package com.mkyong.common.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import com.mkyong.common.form.HelloWorldForm;
public class HelloWorldAction extends Action{
public ActionForward execute(ActionMapping mapping,ActionForm form,
HttpServletRequest request,HttpServletResponse response)
throws Exception {
HelloWorldForm helloWorldForm = (HelloWorldForm) form;
helloWorldForm.setMessage("Hello World! Struts");
return mapping.findForward("success");
}
}
第二个逻辑：
SuggestCommentAction.java :
package org.dlese.dpc.suggest.action;
import org.dlese.dpc.suggest.SuggestUtils;
import org.dlese.dpc.suggest.comment.*;
import org.dlese.dpc.suggest.resource.urlcheck.*;
import org.dlese.dpc.suggest.action.form.SuggestCommentForm;
import org.dlese.dpc.xml.schema.*;
import org.dlese.dpc.xml.*;
import org.dlese.dpc.util.strings.FindAndReplace;
import org.dlese.dpc.vocab.MetadataVocab;
import java.util.*;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.util.MessageResources;
/**
* * Action controller for the Suggest a Comment servlet.
* @version $Id: SuggestCommentAction.java,
*/
public final class SuggestCommentAction extends SuggestAction {
private static boolean debug = true;
private SuggestCommentHelper suggestHelper = null;
/**
* Gets the SuggestCommentHelper attribute of the SuggestCommentAction
* object
*
* @return The SuggestCommentHelper value
* @exception ServletException NOT YET DOCUMENTED
*/
protected SuggestCommentHelper getSuggestHelper () throws ServletException {
if (suggestHelper == null) {
try {
suggestHelper = (SuggestCommentHelper) servlet.getServletContext().getAttribute("SuggestCommentHelper");
if (suggestHelper == null)
throw new Exception ();
} catch (Throwable t) {
throw new ServletException ("SuggestCommentHelper is not initialized");
}
}
return suggestHelper;
}
protected ActionForward initializeSuggestor(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws ServletException {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String id = request.getParameter("id");
if (id == null || id.trim().length() == 0) {
errors.add("error",
new ActionError("comment.id.required"));
saveErrors(request, errors);
return mapping.findForward("home");
}
scf.clear();
scf.setPopup("p".equals( request.getParameter("view")));
scf.setItemID(id);
// ensure the provided record id (itemID) corresponds to an existing record
String itemTitle = null;
String itemURL = null;
try {
Map itemRecordProps = this.getSuggestHelper().getItemRecordProps(id);
scf.setItemURL ((String)itemRecordProps.get ("url"));
scf.setItemTitle((String)itemRecordProps.get ("title"));
} catch (Exception e) {
errors.add("error",
new ActionError("comment.resource.not.found", id));
saveErrors(request, errors);
return mapping.findForward("home");
}
saveMessages(request, errors);
return mapping.findForward("form");
}
// ------------ Command Handlers ----------------------------------
protected ActionForward handleOtherCommands(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String command = request.getParameter("command");
prtln("command: " + command);
throw new ServletException("unsupported command: " + command);
}
protected ActionForward handleEditCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {
SuggestCommentForm scf = (SuggestCommentForm) form;
if (scf.getItemID() == null || scf.getItemID().length() == 0 ) {
prtln("can't edit without a id ... bailing");
return handleStaleData(mapping, form, request);
}
return mapping.findForward("form");
}
protected ActionForward handleCancelCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
scf.clear();
scf.setItemID("");
errors.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("comment.cancel"));
saveMessages(request, errors);
return mapping.findForward("home");
}
protected ActionForward handleDoneCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
// make sure there is a value for URL. If the user has previously "cancelled" and then
// used the back buttons to return to an old form that *looks* like it holds data, but really
// the data has been lost to the app upon cancellation
if (scf.getItemID() == null || scf.getItemID().length() == 0) {
prtln("can't get to done without a itemID ... bailing");
return handleStaleData(mapping, form, request);
}
// Validate
errors = validateSuggestForm(form, mapping, request);
// report errors
if (!errors.isEmpty()) {
saveErrors(request, errors);
return mapping.findForward("form");
}
return mapping.findForward("confirm");
}
protected ActionForward handleSubmitCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
SuggestCommentForm scf = (SuggestCommentForm) form;
// make sure there is a value for URL. If the user has previously "cancelled" and then
// used the back buttons to return to an old form that *looks* like it holds data, but really
// the data has been lost to the app upon cancellation
if (scf.getItemID() == null || scf.getItemID().length() == 0) {
prtln("can't submit without a url ... bailing");
return handleStaleData(mapping, form, request);
}
ActionMessages actionMessages = new ActionMessages();
CommentRecord rec = null;
try {
rec = createRecord(scf);
} catch (Exception e) {
System.out.println("createRecord() failed to set values\n" + e);
e.printStackTrace();
}
// putRecord to DCS
String newId = null;
try {
newId = this.getSuggestHelper().putRecordToDCS(rec);
} catch (Throwable e) {
prtln("putRecord error: " + e.getMessage());
}
boolean notificationSent = false;
try {
new CommentEmailer(newId, this.getSuggestHelper()).sendNotification(scf);
} catch (Exception e) {
prtlnErr ("Email error: " + e.getMessage());
}
if (!notificationSent) {
prtln("Notification NOT sent!");
}
else {
prtln("Notification sent");
}
scf.clear();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("comment.confirmation"));
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
/**
* The required fields for suggest-a-url are: url, nameFirst, nameLast,
* emailPrimary, instName
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected ActionErrors validateSuggestForm(ActionForm form,
ActionMapping mapping,
HttpServletRequest request) {
SuggestCommentForm scf = (SuggestCommentForm) form;
ActionErrors errors = new ActionErrors();
String description = scf.getDescription();
String role = scf.getRole();
String share = scf.getShare();
String nameFirst = scf.getNameFirst();
String nameLast = scf.getNameLast();
String email = scf.getEmail();
String instName = scf.getInstName();
Boolean coppa = scf.getCoppa();
if ((description == null) || (description.trim().equals(""))) {
errors.add("description", new ActionError("field.required", "Comment"));
}
if ((role == null) || (role.trim().equals(""))) {
errors.add("role", new ActionError("field.required", "Role"));
}
if ((share == null) || (share.trim().equals(""))) {
errors.add("share", new ActionError("this.field.required", "Share"));
}
if ((nameFirst == null) || (nameFirst.trim().equals(""))) {
errors.add("nameFirst", new ActionError("field.required", "First Name"));
}
if ((nameLast == null) || (nameLast.trim().equals(""))) {
errors.add("nameLast", new ActionError("field.required", "Last Name"));
}
if (!coppa) {
errors.add("coppa", new ActionError("this.field.required"));
}
if ((instName == null) || (instName.trim().equals(""))) {
errors.add("instName", new ActionError("field.required.an", "Institution or Affiliation"));;
}
if ((email == null) || (email.trim().equals(""))) {
errors.add("email", new ActionError("field.required.an", "Email Address"));
}
else {
try {
SuggestUtils.validateEmail (email);
} catch (Exception e) {
errors.add("email",
new ActionError("generic.error", e.getMessage()));
}
}
return errors;
}
/**
* Update the SuggestionRecord (managed by SuggestCommentHelper) with values
* from the form bean.<P>
*
* @param form NOT YET DOCUMENTED
* @exception Exception Description of the Exception
*/
protected CommentRecord createRecord(ActionForm form)
throws Exception {
SuggestCommentForm scf = (SuggestCommentForm) form;
CommentRecord rec = this.getSuggestHelper().newRecord();
if (rec == null) {
throw new Exception("createRecord could not get a record from SuggestCommentForm");
}
rec.setTitle("Comment on " + scf.getItemTitle());
rec.setItemID(scf.getItemID());
rec.setDescription(scf.getDescription());
rec.setRole(scf.getRole());
rec.setShare(scf.getShare());
rec.setNameFirst(scf.getNameFirst());
rec.setNameLast(scf.getNameLast());
rec.setEmail(scf.getEmail());
rec.setInstName(scf.getInstName());
rec.setCreationDate(SuggestUtils.getBriefDate());
return rec;
}
/**
* Sets the debug attribute of the SuggestCommentAction class
*
* @param db The new debug value
*/
public static void setDebug(boolean db) {
debug = db;
}
/**
* Print a line to standard out.
*/
private static void prtln(String s) {
if (debug) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestCommentAction");
}
}
private static void prtlnErr(String s) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestCommentAction");
}
}
SuggestAction.java
package org.dlese.dpc.suggest.action;
import org.dlese.dpc.suggest.*;
import org.dlese.dpc.suggest.action.form.SuggestForm;
import org.dlese.dpc.xml.schema.*;
import org.dlese.dpc.xml.*;
import org.dlese.dpc.vocab.MetadataVocab;
import java.util.*;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.util.MessageResources;
/**
* Abstract controller for a Suggestor Client. Implements the following flow of
* control:
* <ol>
* <li> Presents form for user input
* <li> Validates input. if there are errors returns user to form, otherwise
* presents confirmation page.
* <li> User can elect to re-edit the form, or "submit" it.
* <li> confirmation page is displayed upon submission
* </ol>
*/
public abstract class SuggestAction extends Action {
private static boolean debug = true;
/**
* Gets the suggestHelper attribute of the SuggestAction object
*
* @return The suggestHelper value
* @exception ServletException NOT YET DOCUMENTED
*/
protected abstract SuggestHelper getSuggestHelper() throws ServletException;
/**
* Gets the schemaHelper attribute of the SuggestAction object
*
* @return The schemaHelper value
*/
protected SchemaHelper getSchemaHelper() {
try {
return getSuggestHelper().getSchemaHelper();
} catch (Exception e) {}
return null;
}
// --------------------------------------------------------- Public Methods
/**
* Processes the specified HTTP request and creates the corresponding HTTP
* response by forwarding to a JSP that will create it. Returns an {@link
* org.apache.struts.action.ActionForward} instance that maps to the Struts
* forwarding name "xxx.xxx," which must be configured in struts-config.xml to
* forward to the JSP page that will handle the request.
*
* @param mapping Description of the Parameter
* @param form Description of the Parameter
* @param request Description of the Parameter
* @param response Description of the Parameter
* @return Description of the Return Value
* @exception IOException Description of the Exception
* @exception ServletException Description of the Exception
*/
public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
/*
Design note:
Only one instance of this class gets created for the app and shared by
all threads. To be thread-safe, use only local variables, not instance
variables (the JVM will handle these properly using the stack). Pass
all variables via method signatures rather than instance vars.
*/
SuggestForm sform = (SuggestForm) form;
SchemaHelper schemaHelper = getSchemaHelper();
sform.setSchemaHelper(schemaHelper);
MetadataVocab vocab = (MetadataVocab) servlet.getServletContext().getAttribute("MetadataVocab");
sform.setVocab(vocab);
ActionErrors errors = new ActionErrors();
ActionMessages actionMessages = new ActionMessages();
// Query Args
String command = request.getParameter("command");
// prtln("\ncommand: " + command + "\n");
org.dlese.dpc.schemedit.SchemEditUtils.showRequestParameters(request);
// HANDLE COMMAND
try {
if (command == null) {
// return handleCancelCommand(mapping, form, request, response);
return initializeSuggestor(mapping, form, request, response);
}
// NEW - present simple form to get (and validate) URL
if (command.equalsIgnoreCase("cancel")) {
return handleCancelCommand(mapping, form, request, response);
}
// EDIT - read record and present form for editing
if (command.equalsIgnoreCase("edit")) {
return handleEditCommand(mapping, form, request, response);
}
// SUBMIT - user has confirmed data - now write it to disk
// data is valid at this point and the user has hit the submit button
if (command.equalsIgnoreCase("submit")) {
return handleSubmitCommand(mapping, form, request, response);
}
// DONE - validate data and present confirmation page to user
if (command.equalsIgnoreCase("done")) {
return handleDoneCommand(mapping, form, request, response);
}
return handleOtherCommands(mapping, form, request, response);
} catch (Exception e) {
prtlnErr("ERROR: " + e.getMessage());
e.printStackTrace();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("generic.error", "Server Error: " + e.getMessage()));
} catch (Throwable t) {
prtlnErr("UNKNOWN ERROR: " + t.getMessage());
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("generic.error", "Unknown Server Error"));
}
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
protected abstract ActionForward initializeSuggestor(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException;
/**
* Hook for subclasses to handle commands that are outside the ones defined in
* this class.
*/
protected ActionForward handleOtherCommands(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws ServletException {
String command = request.getParameter("command");
prtln("command: " + command);
throw new ServletException("unsupported command: " + command);
}
/**
* Populate SuggestionForm, and forward user to edit-form.
* @exception Exception if SuggestionForm cannot be populated with required
* info.
*/
protected abstract ActionForward handleEditCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception;
protected abstract ActionForward handleCancelCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Validate information supplied by user, return to edit form if there are
* errors, or display confirmation page if there are no errors.
*/
protected abstract ActionForward handleDoneCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Attempt to write the suggestion to a DCS instance, forward user to
* confirmation page.
*/
protected abstract ActionForward handleSubmitCommand(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response);
/**
* Return user to suggestor front page and show message explaining that they
* were apparently trying to edit or submit data from a cancelled form
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected ActionForward handleStaleData(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request) {
SuggestForm sForm = (SuggestForm) form;
sForm.clear();
prtln("handleStaleData");
ActionMessages actionMessages = new ActionMessages();
actionMessages.add(ActionMessages.GLOBAL_MESSAGE,
new ActionMessage("stale.data"));
saveMessages(request, actionMessages);
return mapping.findForward("home");
}
/**
* The required fields for suggest-a-url are: url, nameFirst, nameLast,
* emailPrimary, instName
*
* @param mapping Description of the Parameter
* @param request Description of the Parameter
* @param form NOT YET DOCUMENTED
* @return Description of the Return Value
*/
protected abstract ActionErrors validateSuggestForm(ActionForm form,
ActionMapping mapping,
HttpServletRequest request);
/**
* Update the SuggestionRecord (managed by SuggestResourceHelper) with values
* from the form bean
*
* @param form NOT YET DOCUMENTED
* @exception Exception Description of the Exception
*/
protected abstract SuggestionRecord createRecord(ActionForm form) throws Exception;
/**
* Sets the debug attribute of the SuggestAction class
*
* @param db The new debug value
*/
public static void setDebug(boolean db) {
debug = db;
}
/**
* Print a line to standard out.
*
* @param s The String to print.
*/
private static void prtln(String s) {
if (debug) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestAction");
}
}
private static void prtlnErr(String s) {
org.dlese.dpc.schemedit.SchemEditUtils.prtln(s, "SuggestAction");
}
}
抽象基础 class 是一个 classic 命令模式处理程序：
String command = request.getParameter("command");
这决定了执行哪个命令运行。因此，无论是在表单还是 URL 中，通常应该 always/will 是一个 command 来确定流程的其余部分。
默认命令是 cancel、edit、submit 和 done，但实施 classes 可能会通过 handleOtherCommands 函数，在默认实现中抛出错误。
*请注意，在 SuggestCommentAction 中提供了一个无用的实现，该实现执行基础 class 已经执行的操作。
每个实现都应该实现 initializeSuggestor 功能。如果提供 none，此处的实现会提前检查 ID 和 returns。剩下的就是家务；确定它是否显示在弹出窗口中（view 参数），尝试查找记录，并 returns 适当的转发。
edit、cancel、done 和 submit、abstract 在基础 class 中，或多或少做你想做的期望：他们执行数据库操作并将视图路由到为 SuggestCommentAction.
每个实现都应提供处理特定表单验证要求的验证函数。
每个实现都应提供一个 createRecord 函数返回 SuggestionRecord 的实现，在本例中为 CommentRecord。这在很大程度上只是将表单数据编组到域对象中。 （请注意，有些库会自动执行此操作，但如果正在进行大量转换，则并不总是合适的。）
TL;DR:
这是一种为不同域对象委派基本 CRUD 操作的机制，其中每个域对象将由 SuggestAction.
这很可能（很有可能）是相当旧的代码：它打破了我认为是很多功能边界的东西，例如，它依赖于 Struts 1-specific functionality in each执行。在 S1 时代，这相当普遍，因为 S1 的架构和预期使用方式。