最近一直在研究struts2,看了李刚写的一本struts2权威指南,但感觉讲的还是有点浅,但是做为入门的话,还是不错的.现在开始看struts2的源码,但由于本人能力有限,看的是头晕脑涨的,有很多不明白的地方,所以想把不明白的地方贴出来跟大家一起讨论讨论.
其中有一处也觉的是比较关键的一步:
以下是DefaultActionInvocation中的invoke()方法的源码:
Java代码
public String invoke() throws Exception {
String profileKey = "invoke: ";
try {
UtilTimerStack.push(profileKey);
if (executed) {
throw new IllegalStateException("Action has already executed"
;
}
if (interceptors.hasNext()) {
final InterceptorMapping interceptor = (InterceptorMapping) interceptors.next();
UtilTimerStack.profile("interceptor: "+interceptor.getName(),
new UtilTimerStack.ProfilingBlock() {
public String doProfiling() throws Exception {
resultCode = interceptor.getInterceptor().intercept(DefaultActionInvocation.this);
return null;
}
});
} else {
resultCode = invokeActionOnly();
}
// this is needed because the result will be executed, then control will return to the Interceptor, which will
// return above and flow through again
if (!executed) {
if (preResultListeners != null) {
for (Iterator iterator = preResultListeners.iterator();
iterator.hasNext()
{
PreResultListener listener = (PreResultListener) iterator.next();
String _profileKey="preResultListener: ";
try {
UtilTimerStack.push(_profileKey);
listener.beforeResult(this, resultCode);
}
finally {
UtilTimerStack.pop(_profileKey);
}
}
}
// now execute the result, if we're supposed to
if (proxy.getExecuteResult()) {
executeResult();
}
executed = true;
}
return resultCode;
}
finally {
UtilTimerStack.pop(profileKey);
}
}
public String invoke() throws Exception {
String profileKey = "invoke: ";
try {
UtilTimerStack.push(profileKey);
if (executed) {
throw new IllegalStateException("Action has already executed"
;
}
if (interceptors.hasNext()) {
final InterceptorMapping interceptor = (InterceptorMapping) interceptors.next();
UtilTimerStack.profile("interceptor: "+interceptor.getName(),
new UtilTimerStack.ProfilingBlock() {
public String doProfiling() throws Exception {
resultCode = interceptor.getInterceptor().intercept(DefaultActionInvocation.this);
return null;
}
});
} else {
resultCode = invokeActionOnly();
}
// this is needed because the result will be executed, then control will return to the Interceptor, which will
// return above and flow through again
if (!executed) {
if (preResultListeners != null) {
for (Iterator iterator = preResultListeners.iterator();
iterator.hasNext()
{
PreResultListener listener = (PreResultListener) iterator.next();
String _profileKey="preResultListener: ";
try {
UtilTimerStack.push(_profileKey);
listener.beforeResult(this, resultCode);
}
finally {
UtilTimerStack.pop(_profileKey);
}
}
}
// now execute the result, if we're supposed to
if (proxy.getExecuteResult()) {
executeResult();
}
executed = true;
}
return resultCode;
}
finally {
UtilTimerStack.pop(profileKey);
}
}
不明白是怎样迭代执行一个又一个的Interceptor中的intercept方法.
按照我的理解,至少我可以看到一个循环遍厉interceptors这个集合才对.
大家可以讨论讨论,有知道的也可以告诉我.谢谢.
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