package com.johnChnia.coderising2017.litestruts;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import java.io.File;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
public class Struts {
public static View runAction(String actionName, Map<String, String> parameters) throws Exception {
/*
0. 读取配置文件struts.xml
1. 根据actionName找到相对应的class , 例如LoginAction, 通过反射实例化(创建对象)
据parameters中的数据,调用对象的setter方法, 例如parameters中的数据是
("name"="test" , "password"="1234") ,
那就应该调用 setName和setPassword方法
2. 通过反射调用对象的exectue 方法, 并获得返回值,例如"success"
3. 通过反射找到对象的所有getter方法(例如 getMessage),
通过反射来调用, 把值和属性形成一个HashMap , 例如 {"message": "登录成功"} ,
放到View对象的parameters
4. 根据struts.xml中的 <result> 配置,以及execute的返回值, 确定哪一个jsp,
放到View对象的jsp字段中。
*/
SAXReader reader = new SAXReader();
Document document = null;
document = reader.read(new File("target/classes/struts.xml"));
Element node = document.getRootElement();
List<Element> elements = node.elements("action");
Class action = null;
Object actionInstance = null;
Method[] methods = null;
View view = null;
for (Element element :
elements) {
if (element.attribute("name").getValue().equals(actionName)) {
action = Class.forName(element.attribute("class").getValue());
Constructor constructor = action.getConstructor(null);
actionInstance = constructor.newInstance(null);
methods = action.getDeclaredMethods();
Iterator mapIterator = parameters.entrySet().iterator();
while (mapIterator.hasNext()) {
Map.Entry entry = (Map.Entry) mapIterator.next();
Object key = entry.getKey();
Object value = entry.getValue();
for (Method method :
methods) {
if (method.getName().equalsIgnoreCase("set" + key)) {
method.invoke(actionInstance, value);
break;
}
}
}
Method method = action.getMethod("execute", null);
String resultName = (String) method.invoke(actionInstance, null);
Map<String, String> map = new HashMap<>();
Field[] fields = action.getDeclaredFields();
for (Field field :
fields) {
String fieldName = field.getName();
String methodName = "get"
+ fieldName.substring(0, 1).toUpperCase()
+ fieldName.substring(1);
map.put(fieldName,
(String) action.getMethod(methodName, null)
.invoke(actionInstance, null));
}
String jsp = null;
Iterator<Element> xmlIterator = element.elementIterator();
while (xmlIterator.hasNext()) {
Element e = xmlIterator.next();
if (e.attribute("name").getValue().equals(resultName)) {
jsp = e.getTextTrim();
}
}
view = new View();
view.setParameters(map);
view.setJsp(jsp);
}
}
return view;
}
}