@Override
public String doIntercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();//獲取當(dāng)前執(zhí)行的Action對(duì)象
if (!(action instanceof NoParameters)) {//判斷Action是否實(shí)現(xiàn)了NoParameters接口，實(shí)現(xiàn)該接口表示該Action沒有任何請求參數(shù)
ActionContext ac = invocation.getInvocationContext();//獲取ActionContext對(duì)象
final Map<String, Object> parameters = retrieveParameters(ac);//獲取請求參數(shù)Map
//省略...
if (parameters != null) {//如果請求參數(shù)不為null
Map<String, Object> contextMap = ac.getContextMap();//獲取ActionContext內(nèi)部的context Map，即OgnlContext對(duì)象
try {
//省略...
ValueStack stack = ac.getValueStack();//獲取值棧
setParameters(action, stack, parameters);//為值棧設(shè)置參數(shù)
} finally {
//省略...
}
}
}
return invocation.invoke();//調(diào)用下一個(gè)攔截器
}

protected void setParameters(Object action, ValueStack stack, final Map<String, Object> parameters) {
ParameterNameAware parameterNameAware = (action instanceof ParameterNameAware)
? (ParameterNameAware) action : null;//判斷Action有無實(shí)現(xiàn)ParameterNameAware接口
Map<String, Object> params;
Map<String, Object> acceptableParameters;//合法參數(shù)集合
//判斷參數(shù)設(shè)置是否有序，ordered默認(rèn)為false，即無序
if (ordered) {
params = new TreeMap<String, Object>(getOrderedComparator());//如果有序則要獲取比較器
acceptableParameters = new TreeMap<String, Object>(getOrderedComparator());
params.putAll(parameters);
} else {
params = new TreeMap<String, Object>(parameters);
acceptableParameters = new TreeMap<String, Object>();
}
//迭代請求參數(shù)
for (Map.Entry<String, Object> entry : params.entrySet()) {
String name = entry.getKey();
//判斷參數(shù)是否合法，如果Action實(shí)現(xiàn)了ParameterNameAware則acceptableName(name)返回true且parameterNameAware.acceptableParameterName(name)
//也返回true該參數(shù)才是合法的；如果Action沒有實(shí)現(xiàn)ParameterNameAware則參數(shù)是否合法由acceptableName(name)方法決定
boolean acceptableName = acceptableName(name) && (parameterNameAware == null || parameterNameAware.acceptableParameterName(name));
//如果參數(shù)合法
if (acceptableName) {
acceptableParameters.put(name, entry.getValue());//把合法參數(shù)添加到合法參數(shù)集合中
}
}
ValueStack newStack = valueStackFactory.createValueStack(stack);
//省略...
for (Map.Entry<String, Object> entry : acceptableParameters.entrySet()) {//迭代合法參數(shù)
String name = entry.getKey();//參數(shù)名
Object value = entry.getValue();//參數(shù)值
try {
newStack.setValue(name, value);//將該參數(shù)設(shè)置到ValueStack中
} catch (RuntimeException e) {
//省略...
}
}
//省略...
//看該方法的名稱是將合法參數(shù)添加到ActionContext中，但在該攔截器中，該方法為空實(shí)現(xiàn)，無任何代碼
//該方法被聲明為protected，即子類可以覆蓋該方法以改變行為
addParametersToContext(ActionContext.getContext(), acceptableParameters);
}

protected boolean acceptableName(String name) {
//調(diào)用isAccepted與isExcluded方法判斷
if (isAccepted(name) && !isExcluded(name)) {
return true;
}
return false;
}

protected boolean isAccepted(String paramName) {
if (!this.acceptParams.isEmpty()) {
for (Pattern pattern : acceptParams) {
Matcher matcher = pattern.matcher(paramName);
if (matcher.matches()) {
return true;
}
}
return false;
} else
return acceptedPattern.matcher(paramName).matches();
}
protected boolean isExcluded(String paramName) {
if (!this.excludeParams.isEmpty()) {
for (Pattern pattern : excludeParams) {
Matcher matcher = pattern.matcher(paramName);
if (matcher.matches()) {
return true;
}
}
}
return false;
}