Spring的解析源码
public void parseReplacedMethodSubElements(Element beanEle, MethodOverrides overrides) {
NodeList nl = beanEle.getChildNodes();
for (int i = 0; i < nl.getLength(); i++) {
Node node = nl.item(i);
//仅当在Spring默认bean的子元素下且为
if (isCandidateElement(node) && nodeNameEquals(node, REPLACED_METHOD_ELEMENT)) {
Element replacedMethodEle = (Element) node;
//提取要替换的旧的方法
String name = replacedMethodEle.getAttribute(NAME_ATTRIBUTE);
//提取对应的新的替换方法
String callback = replacedMethodEle.getAttribute(REPLACER_ATTRIBUTE);
ReplaceOverride replaceOverride = new ReplaceOverride(name, callback);
// Look for arg-type match elements.
List<Element> argTypeEles = DomUtils.getChildElementsByTagName(replacedMethodEle, ARG_TYPE_ELEMENT);
//记录参数
for (Element argTypeEle : argTypeEles) {
String match = argTypeEle.getAttribute(ARG_TYPE_MATCH_ATTRIBUTE);
match = (StringUtils.hasText(match) ? match : DomUtils.getTextValue(argTypeEle));
if (StringUtils.hasText(match)) {
replaceOverride.addTypeIdentifier(match);
}
}
replaceOverride.setSource(extractSource(replacedMethodEle));
overrides.addOverride(replaceOverride);
}
}
}
replaced-method的使用
public class LookupMethodBean {
public void test(){
System.out.println("原始方法!");
}
}
public class MethodReplace implements MethodReplacer {
public Object reimplement(Object obj, Method method, Object[] args) throws Throwable {
System.out.println("方法已经被替换!");
return null;
}
}
<bean name="replacer" class="MethodReplace"> </bean>
<bean name="testBean" class="LookupMethodBean">
<replaced-method name="test" replacer="replacer"> </replaced-method >
</bean>