package com.coderising.litestruts;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.io.File;
import java.io.FileNotFoundException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
public class Struts {
private static Struts instance = null;
private static Map<String, StrutsXml> strutsXml;
private Struts() {
}
/**
* 单例模式初始化struts.xml，而不是每次跑runAction的时候都要初始化一次
*
* @return
*/
public static Struts init() throws FileNotFoundException {
if (instance == null) {
/**
* 0. 读取配置文件struts.xml
*/
//创建SAXReader对象
SAXReader reader = new SAXReader();
//读取文件 转换成Document
Document document = null;
try {
document = reader.read(new File("src/com/coding/coderising/litestruts/struts.xml"));
} catch (DocumentException e) {
e.printStackTrace();
}
//获取根节点元素对象
Element root = document.getRootElement();
if ("struts".equals(root.getName())) {
strutsXml = new HashMap<String, StrutsXml>();
Iterator<Element> actions = root.elementIterator();
while (actions.hasNext()) {
Element action = actions.next();
List<Attribute> attrList = action.attributes();
String actionName = null;
StrutsXml xml = null;
if (!"action".equals(action.getName())) {
continue;
}
//遍历属性节点
for (Attribute attribute : attrList) {
xml = new StrutsXml();
if ("name".equals(attribute.getName())) {
actionName = attribute.getValue();
}
if ("class".equals(attribute.getName())) {
xml.setClazz(attribute.getValue());
//获取result信息
Iterator<Element> results = action.elementIterator();
while (results.hasNext()) {
Element result = results.next();
List<Attribute> resultList = result.attributes();
for (Attribute resultAttr : resultList) {
//System.out.println(resultAttr.getValue() + " ,"+result.getText());
xml.getResult().put(resultAttr.getValue(), result.getText());
}
}
}
//System.out.println("属性"+attribute.getName() +":" + attribute.getValue());
}
strutsXml.put(actionName, xml);
}
} else {
throw new FileNotFoundException("not a struts XML file !");
}
instance = new Struts();
}
return instance;
}
public static View runAction(String actionName, Map<String, String> parameters) {
if (instance == null) return null;
if (actionName == null || "".equals(actionName.trim())) return null;
View view = new View();
StrutsXml struts = strutsXml.get(actionName);
Class clazz = null;
/**
* 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
*/
//获取相应处理的action
if (struts != null) {
String className = struts.getClazz();
try {
clazz = Class.forName(className);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
} else {
throw new NullPointerException("action not found in struts file !");
}
if (clazz != null) {
Object action = null;
try {
action = clazz.newInstance();
//反射调用设置参数
for (Map.Entry<String, String> entry : parameters.entrySet()) {
String para = entry.getKey();
if (!checkField(clazz, para)) continue;
//根据习惯，类的属性首字母在调用时大写，例如属性名是 age，则类方法为getAge
PropertyDescriptor pd = new PropertyDescriptor(para, clazz);
Method setMethod = pd.getWriteMethod();//获得set方法
setMethod.invoke(action, entry.getValue());
}
/**
* 2. 通过反射调用对象的exectue 方法， 并获得返回值，例如"success"
*/
//执行execute()
Method excuteMethod = clazz.getDeclaredMethod("execute");
String result = (String) excuteMethod.invoke(action);
//通过xml文件获取返回值
String jsp = struts.getResult().get(result);
if (jsp == null || jsp.trim().equals("")) {
throw new NullPointerException("the requested file is not found !");
}
/**
* 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
*/
//执行get方法
Map<String, String> viewMap = new HashMap<>();
Field[] fields = clazz.getDeclaredFields();//获得属性
for (Field field : fields) {
String getMethodName = "get" + field.getName().substring(0, 1).toUpperCase() + field.getName().substring(1);
Method getMethod = clazz.getDeclaredMethod(getMethodName);
String returnVal = (String) getMethod.invoke(action);
viewMap.put(field.getName(), returnVal);
}
/**
* 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。
*/
view.setJsp(jsp);
view.setParameters(viewMap);
} catch (IntrospectionException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
}
}
return view;
}
private static boolean checkField(Class clazz, String fieldName) {
if (fieldName == null || fieldName.trim().equals("")) return false;
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if (fieldName.equals(field.getName())) return true;
}
return false;
}
public static void main(String args[]) {
try {
Struts.init();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Map<String, String> paras = new HashMap<>();
paras.put("name", "test");
paras.put("password", "1234");
View view = Struts.runAction("login", paras);
}
}
class StrutsXml {
private String actionName;
private String clazz;
private Map<String, String> result = new HashMap<>();
public StrutsXml(String actionName, String clazz, Map<String, String> result) {
this.actionName = actionName;
this.clazz = clazz;
this.result = result;
}
public StrutsXml() {
}
public String getActionName() {
return actionName;
}
public void setActionName(String actionName) {
this.actionName = actionName;
}
public String getClazz() {
return clazz;
}
public void setClazz(String clazz) {
this.clazz = clazz;
}
public Map<String, String> getResult() {
return result;
}
public void setResult(Map<String, String> result) {
this.result = result;
}
}