struts源码初步研究
struts1.3.8源码初步学习
先介绍一下HttpServlet
一下的代码是有jd（反编译工具，个人觉得还是不错的）反编译过来的 仅供参考
HttpServlet
/* */ public abstract class HttpServlet extends GenericServlet
/* */ implements Serializable
/* */ {
//doGet方法
/* */ protected void doGet(HttpServletRequest req, HttpServletResponse resp)
/* */ throws ServletException, IOException
/* */ {
}
//doPost方法
/* */ protected void doPost(HttpServletRequest req, HttpServletResponse resp)
/* */ throws ServletException, IOException
/* */ {
/* 386 */ String protocol = req.getProtocol();
/* 387 */ String msg = lStrings.getString("http.method_post_not_supported");
/* 388 */ if (protocol.endsWith("1.1"))
/* 389 */ resp.sendError(405, msg);
/* */ else
/* 391 */ resp.sendError(400, msg);
/* */ }
//doHead方法
/* */ protected void doHead(HttpServletRequest req, HttpServletResponse resp)
/* */ throws ServletException, IOException
/* */ {
/* 311 */ NoBodyResponse response = new NoBodyResponse(resp);
/* */
/* 313 */ doGet(req, response);
/* 314 */ response.setContentLength();
/* */ }
...........
//这里负责调用doGet或者doPost方法
/* */ protected void service(HttpServletRequest req, HttpServletResponse resp)
/* */ throws ServletException, IOException
/* */ {
/* 733 */ String method = req.getMethod();
/* */
/* 735 */ if (method.equals("GET")) {
/* 736 */ long lastModified = getLastModified(req);
/* 737 */ if (lastModified == -1L)
/* */ {
/* 740 */ doGet(req, resp);
/* */ } else {
/* 742 */ long ifModifiedSince = req.getDateHeader("If-Modified-Since");
/* 743 */ if (ifModifiedSince < lastModified / 1000L * 1000L)
/* */ {
/* 747 */ maybeSetLastModified(resp, lastModified);
/* 748 */ doGet(req, resp);
/* */ } else {
/* 750 */ resp.setStatus(304);
/* */ }
/* */ }
/* */ }
/* 754 */ else if (method.equals("HEAD")) {
/* 755 */ long lastModified = getLastModified(req);
/* 756 */ maybeSetLastModified(resp, lastModified);
/* 757 */ doHead(req, resp);
/* */ }
/* 759 */ else if (method.equals("POST")) {
/* 760 */ doPost(req, resp);
/* */ }
/* 762 */ else if (method.equals("PUT")) {
/* 763 */ doPut(req, resp);
/* */ }
/* 765 */ else if (method.equals("DELETE")) {
/* 766 */ doDelete(req, resp);
/* */ }
/* 768 */ else if (method.equals("OPTIONS")) {
/* 769 */ doOptions(req, resp);
/* */ }
/* 771 */ else if (method.equals("TRACE")) {
/* 772 */ doTrace(req, resp);
/* */ }
/* */ else
/* */ {
/* 780 */ String errMsg = lStrings.getString("http.method_not_implemented");
/* 781 */ Object[] errArgs = new Object[1];
/* 782 */ errArgs[0] = method;
/* 783 */ errMsg = MessageFormat.format(errMsg, errArgs);
/* */
/* 785 */ resp.sendError(501, errMsg);
/* */ }
/* */ }
/* */ }
下面开始介绍一些struts的源码，来自struts-1.3.8-all.zip
1.action
public class Action {
.....
public ActionForward execute(ActionMapping mapping, ActionForm form,
ServletRequest request, ServletResponse response)
throws Exception {
try {
return execute(mapping, form, (HttpServletRequest) request,
(HttpServletResponse) response);
} catch (ClassCastException e) {
return null;
}
}
//每个action都要实现这个方法
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
return null;
}
....
}
2.actionServlet
public class ActionServlet extends HttpServlet {
....
public void init() throws ServletException {
....
}
public void destroy() {
....
}
/**
* <p>Perform the standard request processing for this request, and create
* the corresponding response.</p>
*
* @param request The servlet request we are processing
* @param response The servlet response we are creating
* @throws IOException if an input/output error occurs
* @throws ServletException if a servlet exception is thrown
*/
//多有的方法doGet,doPost方法都走这里，并交给processor去调用处理相关
protected void process(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
ModuleUtils.getInstance().selectModule(request, getServletContext());
ModuleConfig config = getModuleConfig(request);
RequestProcessor processor = getProcessorForModule(config);
if (processor == null) {
processor = getRequestProcessor(config);
}
//在这里,交由RequestProcessor去处理，下面会详细说明
processor.process(request, response);
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
//注意这里
process(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
//同样注意这里
process(request, response);
}
....
}
3.RequestProcessor
public class RequestProcessor {
....
public void process(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
// Wrap multipart requests with a special wrapper
request = processMultipart(request);
// Identify the path component we will use to select a mapping
String path = processPath(request, response);
if (path == null) {
return;
}
if (log.isDebugEnabled()) {
log.debug("Processing a '" + request.getMethod() + "' for path '"
+ path + "'");
}
// Select a Locale for the current user if requested
processLocale(request, response);
// Set the content type and no-caching headers if requested
processContent(request, response);
processNoCache(request, response);
// General purpose preprocessing hook
if (!processPreprocess(request, response)) {
return;
}
this.processCachedMessages(request, response);
// Identify the mapping for this request
ActionMapping mapping = processMapping(request, response, path);
if (mapping == null) {
return;
}
// Check for any role required to perform this action
if (!processRoles(request, response, mapping)) {
return;
}
// Process any ActionForm bean related to this request
ActionForm form = processActionForm(request, response, mapping);
processPopulate(request, response, form, mapping);
// Validate any fields of the ActionForm bean, if applicable
try {
if (!processValidate(request, response, form, mapping)) {
return;
}
} catch (InvalidCancelException e) {
ActionForward forward = processException(request, response, e, form, mapping);
processForwardConfig(request, response, forward);
return;
} catch (IOException e) {
throw e;
} catch (ServletException e) {
throw e;
}
// Process a forward or include specified by this mapping
if (!processForward(request, response, mapping)) {
return;
}
if (!processInclude(request, response, mapping)) {
return;
}
// Create or acquire the Action instance to process this request
Action action = processActionCreate(request, response, mapping);
if (action == null) {
return;
}
//这里是重点
// Call the Action instance itself
ActionForward forward =
processActionPerform(request, response, action, form, mapping);
// Process the returned ActionForward instance
processForwardConfig(request, response, forward);
}
//这个方法调用action的execute的方法
protected ActionForward processActionPerform(HttpServletRequest request,
HttpServletResponse response, Action action, ActionForm form,
ActionMapping mapping)
throws IOException, ServletException {
try {
//看这里，大家大概明白了吧 呵呵
return (action.execute(mapping, form, request, response));
} catch (Exception e) {
return (processException(request, response, e, form, mapping));
}
}
...
}