Handler 處理流程
doFilter - Handler 鏈中每個 handler.handle(...)
容器初始化時訪問 web.xml 配置的 JFinalFilter.doFilter。沿著 Handler 鏈，每個 handler 調用 handle 方法進行處理，然後交給下一個 handler。
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
// 獲取 request、response，設置編碼
HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)res;
request.setCharacterEncoding(encoding);
// 初始化的時候可以看出 contextPathLength 為 0 或者為 項目名稱的長度
// 比如 target = webapp/xx/yy/zz，則截取後的 target = /xx/yy/zz
String target = request.getRequestURI();
if (contextPathLength != 0)
target = target.substring(contextPathLength);
// 在調用了 ActionHandler的 handle 方法之後，isHandled[0] 才會被置為 true。
boolean[] isHandled = {false};
try {
// 重頭戲，handler 鏈首到鏈尾 ActionHandler 依次進行處理
handler.handle(target, request, response, isHandled);
}
catch (Exception e) {
if (log.isErrorEnabled()) {
String qs = request.getQueryString();
log.error(qs == null ? target : target + "?" + qs, e);
}
}
// 若最後 isHandled[0] = false，會執行下一個 Filter。
if (isHandled[0] == false)
chain.doFilter(request, response);
}
JFinal 初始化過程中可以 add JFinal 庫中的Handler 或自定義的 Handler。
例如：ContextPathHandler，JFinal 自身擴展的 Handler。
訪問項目時就會走過 handler 方法設置 contextPath。這樣在前端就可以通過 ${CONTEXT_PATH} 得到項目根路徑。
public class ContextPathHandler extends Handler {
private String contextPathName;
public ContextPathHandler() {
contextPathName = "CONTEXT_PATH";
}
public ContextPathHandler(String contextPathName) {
if (StrKit.isBlank(contextPathName))
throw new IllegalArgumentException("contextPathName can not be blank.");
this.contextPathName = contextPathName;
}
public void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
request.setAttribute(contextPathName, request.getContextPath());
System.out.println("哈哈哈");
next.handle(target, request, response, isHandled);
}
}
FakeStaticHandler，也是 JFinal 自身擴展的 Handler。new FakeStaticHandler 時可定義後綴，訪問路徑 target 必須是以這個後綴結尾才可以進行下去。
public class FakeStaticHandler extends Handler {private String viewPostfix;
public FakeStaticHandler() {
viewPostfix= ".html";
}
public FakeStaticHandler(String viewPostfix) {
if (StrKit.isBlank(viewPostfix))
throw new IllegalArgumentException("viewPostfix can not be blank.");
this.viewPostfix = viewPostfix;
}
public void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
if ("/".equals(target)) {
next.handle(target, request, response, isHandled);
return;
}
if (target.indexOf('.') == -1) {
HandlerKit.renderError404(request, response, isHandled);
return ;
}
int index = target.lastIndexOf(viewPostfix);
if (index != -1)
target= target.substring(0, index);
next.handle(target, request, response, isHandled);
}
}
到達 Handler 鏈尾 ActionHandler 處理
訪問交給 Handler 鏈尾 ActionHandler，調用 handle 方法進行處理：根據訪問路徑 target 得到 Action，由 Action 得到 Controller。接著 new Invocation(action, controller).invoke() 進入責任鏈，反射機制調用 Controller 的方法處理（此方法可根據 Action 得到）。
public final void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
if (target.indexOf('.') != -1) {
return ;
}
isHandled[0] = true;
String[] urlPara= {null};
// actionMapping 根據 target 得到對應的 action
Action action = actionMapping.getAction(target, urlPara);
if (action == null) {
if (log.isWarnEnabled()) {
String qs= request.getQueryString();
log.warn("404 Action Not Found: " + (qs == null ? target : target + "?" + qs));
}
renderFactory.getErrorRender(404).setContext(request, response).render();
return ;
}
try {
// 由 action 得到對應的 Controller
Controller controller = action.getControllerClass().newInstance();
// Controller 初始化
controller.init(request, response, urlPara[0]);
if (devMode) {
if (ActionReporter.isReportAfterInvocation(request)) {
new Invocation(action, controller).invoke();
ActionReporter.report(controller, action);
}else {
ActionReporter.report(controller, action);
new Invocation(action, controller).invoke();
}
}
else {
// 調用 Controller 相應的處理方法
new Invocation(action, controller).invoke();
}
// 獲取對應的 Render，如果是一個 ActionRender，就再交給 handler 處理；如果 Render == null會按照默認Render處理；
Render render = controller.getRender();
if (render instanceof ActionRender) {
String actionUrl= ((ActionRender)render).getActionUrl();
if (target.equals(actionUrl))
throw new RuntimeException("The forward action url is the same as before.");
else
handle(actionUrl, request, response, isHandled);
return ;
}
if (render == null)
render= renderFactory.getDefaultRender(action.getViewPath() + action.getMethodName());
// 調用 Render 實現類講數據寫入頁面
render.setContext(request, response, action.getViewPath()).render();
}
catch (RenderException e) {
if (log.isErrorEnabled()) {
String qs= request.getQueryString();
log.error(qs== null ? target : target + "?" + qs, e);
}
}
catch (ActionException e) {
int errorCode = e.getErrorCode();
if (errorCode == 404 && log.isWarnEnabled()) {
String qs= request.getQueryString();
log.warn("404 Not Found: " + (qs == null ? target : target + "?" + qs));
}
else if (errorCode == 401 && log.isWarnEnabled()) {
String qs= request.getQueryString();
log.warn("401 Unauthorized: " + (qs == null ? target : target + "?" + qs));
}
else if (errorCode == 403 && log.isWarnEnabled()) {
String qs= request.getQueryString();
log.warn("403 Forbidden: " + (qs == null ? target : target + "?" + qs));
}
else if (log.isErrorEnabled()) {
String qs= request.getQueryString();
log.error(qs== null ? target : target + "?" + qs, e);
}
e.getErrorRender().setContext(request, response, action.getViewPath()).render();
}
catch (Throwable t) {
if (log.isErrorEnabled()) {
String qs= request.getQueryString();
log.error(qs== null ? target : target + "?" + qs, t);
}
renderFactory.getErrorRender(500).setContext(request, response, action.getViewPath()).render();
}
}View Cod
下面看看攔截器鏈如何處理
public class Invocation {
private Action action;
private static final Object[] NULL_ARGS = new Object[0]; // Prevent new Object[0] by jvm for paras of action invocation.
boolean useInjectTarget;
private Object target;
private Method method;
private Object[] args;
private MethodProxy methodProxy;
private Interceptor[] inters;
private Object returnValue = null;
private int index = 0;
// InvocationWrapper need this constructor
protected Invocation() {
this.action = null;
}
public Invocation(Action action, Controller controller) {
this.action = action;
this.inters = action.getInterceptors();
this.target = controller;
this.args = NULL_ARGS;
}
public Invocation(Object target, Method method, Object[] args, MethodProxy methodProxy, Interceptor[] inters) {
this.action = null;
this.target = target;
this.method = method;
this.args = args;
this.methodProxy = methodProxy;
this.inters = inters;
}
public void invoke() {
if (index < inters.length) {
inters[index++].intercept(this);
}
else if (index++ == inters.length) { // index++ ensure invoke action only one time
try {
// Invoke the action
if (action != null) {
returnValue= action.getMethod().invoke(target, args);
}
// Invoke the method
else {
// if (!Modifier.isAbstract(method.getModifiers()))
// returnValue = methodProxy.invokeSuper(target, args);
if (useInjectTarget)
returnValue= methodProxy.invoke(target, args);
else
returnValue= methodProxy.invokeSuper(target, args);
}
}
catch (InvocationTargetException e) {
Throwable t= e.getTargetException();
throw t instanceof RuntimeException ? (RuntimeException)t : new RuntimeException(e);
}
catch (RuntimeException e) {
throw e;
}
catch (Throwable t) {
throw new RuntimeException(t);
}
}
}
// ... many sets and gets
}
public class AInterceptor implements Interceptor {
public void intercept(Invocation inv) {
System.out.println("Before invoking ");
inv.invoke();
System.out.println("After invoking ");
}
}
public class BInterceptor implements Interceptor {
public void intercept(Invocation inv) {
System.out.println("Before invoking ");
inv.invoke();
System.out.println("After invoking ");
}
}
public class BInterceptor implements Interceptor {
public void intercept(Invocation inv) {
System.out.println("Before invoking ");
inv.invoke();
System.out.println("After invoking ");
}
}
new Invocation(action, controller).invoke()，由 action 得到攔截器數組，如果數組為空，就可以利用反射機制進入 Controller 的方法進行處理的了；
如果攔截器數組不為空，就會遇到攔截器1 的攔截 - inters[0].intercept(this)，數組下標 +1，攔截器1 繼續調用這個 Invocation 實例的 invoke() 方法，並且會在前後加上一些目的性操作；
若下標未越界，接著會遇到攔截器2 的攔截 - inters[1].intercept(this)，數組下標 +1，攔截器2 繼續調用這個 Invocation 實例的 invoke() 方法，並且會在前面加上一些目的性操作；
如此繼續直到下標越界，接著反射機制進入 Controller 的方法進行處理。
render(...)
接著上面 ActionHandler.handle 繼續，在 Controller 方法處理的最後，往往要調用 render 方法來實例化 render 變量。例如，我自定義的一個 IndexController，在最後一步調用 render("next.html")。
public class IndexController extends Controller {
public void index() {
// ...
render("next.html");
}
}
用到父類 Controller 的 render 方法，通過 renderFactory.getRender 得到 render 實例。
public abstract class Controller {
// ...
// render below ---
private static final RenderFactory renderFactory = RenderFactory.me();
/**
* Hold Render object when invoke renderXxx(...)
*/
private Render render;
public Render getRender() {
return render;
}
/**
* Render with any Render which extends Render
*/
public void render(Render render) {
this.render = render;
}
/**
* Render with view use default type Render configured in JFinalConfig
*/
public void render(String view) {
render= renderFactory.getRender(view);
}
/**
* Render with jsp view
*/
public void renderJsp(String view) {
render= renderFactory.getJspRender(view);
}
/**
* Render with freemarker view
*/
public void renderFreeMarker(String view) {
render= renderFactory.getFreeMarkerRender(view);
}
/**
* Render with velocity view
*/
public void renderVelocity(String view) {
render= renderFactory.getVelocityRender(view);
}
/**
* Render with json
* <p>
* Example:<br>
* renderJson("message", "Save successful");<br>
* renderJson("users", users);<br>
*/
public void renderJson(String key, Object value) {
render= renderFactory.getJsonRender(key, value);
}
/**
* Render with json
*/
public void renderJson() {
render= renderFactory.getJsonRender();
}
/**
* Render with attributes set by setAttr(...) before.
* <p>
* Example: renderJson(new String[]{"blogList", "user"});
*/
public void renderJson(String[] attrs) {
render= renderFactory.getJsonRender(attrs);
}
/**
* Render with json text.
* <p>
* Example: renderJson("{\"message\":\"Please input password!\"}");
*/
public void renderJson(String jsonText) {
render= renderFactory.getJsonRender(jsonText);
}
/**
* Render json with object.
* <p>
* Example: renderJson(new User().set("name", "JFinal").set("age", 18));
*/
public void renderJson(Object object) {
render= object instanceof JsonRender ? (JsonRender)object : renderFactory.getJsonRender(object);
}
/**
* Render with text. The contentType is: "text/plain".
*/
public void renderText(String text) {
render= renderFactory.getTextRender(text);
}
/**
* Render with text and content type.
* <p>
* Example: renderText("<user id='5888'>James</user>", "application/xml");
*/
public void renderText(String text, String contentType) {
render= renderFactory.getTextRender(text, contentType);
}
/**
* Render with text and ContentType.
* <p>
* Example: renderText("<html>Hello James</html>", ContentType.HTML);
*/
public void renderText(String text, ContentType contentType) {
render= renderFactory.getTextRender(text, contentType);
}
/**
* Forward to an action
*/
public void forwardAction(String actionUrl) {
render= new ActionRender(actionUrl);
}
/**
* Render with file
*/
public void renderFile(String fileName) {
render= renderFactory.getFileRender(fileName);
}
/**
* Render with file
*/
public void renderFile(File file) {
render= renderFactory.getFileRender(file);
}
/**
* Redirect to url
*/
public void redirect(String url) {
render= renderFactory.getRedirectRender(url);
}
/**
* Redirect to url
*/
public void redirect(String url, boolean withQueryString) {
render= renderFactory.getRedirectRender(url, withQueryString);
}
/**
* Render with view and status use default type Render configured in JFinalConfig
*/
public void render(String view, int status) {
render= renderFactory.getRender(view);
response.setStatus(status);
}
/**
* Render with url and 301 status
*/
public void redirect301(String url) {
render= renderFactory.getRedirect301Render(url);
}
/**
* Render with url and 301 status
*/
public void redirect301(String url, boolean withQueryString) {
render= renderFactory.getRedirect301Render(url, withQueryString);
}
/**
* Render with view and errorCode status
*/
public void renderError(int errorCode, String view) {
throw new ActionException(errorCode, renderFactory.getErrorRender(errorCode, view));
}
/**
* Render with render and errorCode status
*/
public void renderError(int errorCode, Render render) {
throw new ActionException(errorCode, render);
}
/**
* Render with view and errorCode status configured in JFinalConfig
*/
public void renderError(int errorCode) {
throw new ActionException(errorCode, renderFactory.getErrorRender(errorCode));
}
/**
* Render nothing, no response to browser
*/
public void renderNull() {
render= renderFactory.getNullRender();
}
/**
* Render with javascript text. The contentType is: "text/javascript".
*/
public void renderJavascript(String javascriptText) {
render= renderFactory.getJavascriptRender(javascriptText);
}
/**
* Render with html text. The contentType is: "text/html".
*/
public void renderHtml(String htmlText) {
render= renderFactory.getHtmlRender(htmlText);
}
/**
* Render with xml view using freemarker.
*/
public void renderXml(String view) {
render= renderFactory.getXmlRender(view);
}
public void renderCaptcha() {
render= renderFactory.getCaptchaRender();
}
}
根據 Controller 可以看出還能使用 renderJosn、renderText 等多種方法，這裡一筆帶過。
就先寫到這裡吧~~
----- End -----
Jfinal學習之路---Controller使用 http://www.linuxidc.com/Linux/2014-07/104323.htm
JFinal開發8個常見問題 http://www.linuxidc.com/Linux/2015-02/113421.htm
JFinal的詳細介紹：請點這裡
JFinal的下載地址：請點這裡
