今天講的是MVC優化版~
在上篇部落格自定義MVC——1中已經實作了簡易的計算機操作，但是有些代碼可以更加優化，并且作用性更強的。接下來要通過XML對自定義mvc架構進行增強。
将Action運用到XML
首先在Dispatchersevlet中的init()方法中，原有的
actionMap.put("/addCal",new AddCalAction());
actionMap.put("/delCal",new DelCalAction());
actionMap.put("/chenCal",new ChenCalAction());
actionMap.put("/chuCal",new ChuCalAction());
這種方法把路徑寫死了，不友善，
所有改成使用Action來寫，運用工廠模式，可以從XML裡面進行配置，
public void init() {
try {
configMode = ConfigModelFactory.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
}
2，跳轉調整
原有的跳轉是通過servlet重定向或者轉發完成的，但這樣就出現一個問題，每個servlet都得寫着一句，所有有些繁瑣，這也是可以優化的：
1，首先在每一個servlet方法中，将方法傳回值改為String，傳回的是要跳轉或者重定向的路徑 。例（增加）：
public String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(num1)+Integer.valueOf(num2));
return "calRes";
}
2，通過Action工廠模式獲得redirect，獲得這個判斷是否重定向，
然後在Dispatchersevlet中進行判斷，true代表重定向，false代表轉發。
String jsppath = forwardModel.getPath();
if(!"false".equals(forwardModel.getRedirect())) {
resp.sendRedirect(req.getContextPath()+jsppath);
}
else {
req.getRequestDispatcher(jsppath).forward(req, resp);
}
3，反射調用方法
現在這種情況，servlet要根據需求來操作的話，要寫很多個servlet，所有對于這個也是可以強化一下的：
1，之前的Action 隻能處理一個實體類的一個業務，現在要寫一個增強版的Action，凡是這個實體類的操作，對應的方法都可以寫在目前增強版的子控制器來完成。
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ActionSupport implements Action{
@Override
public final String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String methodName = req.getParameter("methodName");
String code = null;
try {
Method method = this.getClass().getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
method.setAccessible(true);
code = (String) method.invoke(this, req,resp);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
}
return code;
}
}
傳回的則是跳轉或者重定向的路徑。
2，然後建立一個專門處理事務的類，CalAction，所有的操作都由這個類來解決。
package com.web;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.zking.framework.ActionSupport;
import com.zking.framework.ModelDriven;
public class CalAction extends ActionSupport {
public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(num1)+Integer.valueOf(num2));
return "calRes";
}
public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(num1)-Integer.valueOf(num2));
return "calRes";
}
public String chen(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(num1)*Integer.valueOf(num2));
return "calRes";
}
public String chu(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String num1 = req.getParameter("num1");
String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(num1)/Integer.valueOf(num2));
return "calRes";
}
}
然後在Dispatchersevlet中擷取：
String code = action.execute(req, resp);
ForwardModel forwardModel = actionModel.get(code);
大概思路就是：首先通過XML解析獲得Cal.jsp要進入的action,通過這個路徑獲得類對象，然後通過這個類對象繼承了的ActionSupport的execute方法傳過來的req獲得參數，通過這個參數可以知道進行調用哪個方法。然後傳回路徑code。通過這個路徑code獲得傳回路徑：
<forward name="calRes" path="calRes.jsp" redirect="false" />
<forward name="success" path="/main.jsp" redirect="true" />
</action>
4，使參數進行自動封裝
在處理事務界面，每個參數都得自己擷取，這有些麻煩，能否讓這些參數自動封裝然後調用呢？
1，首先建立一個模型驅動接口，用來處理JSP頁面傳遞過來的參數，将所有的參數自動封裝到實體類T中：
public interface ModelDriven<T> {
T getMoadel ();
}
2，在處理界面實作這個接口，然後執行個體化一個對象，：
package com.web;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.zking.entity.Cal;
import com.zking.framework.ActionSupport;
import com.zking.framework.ModelDriven;
public class CalAction extends ActionSupport implements ModelDriven<Cal>{
private Cal cal = new Cal();
public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String num1 = req.getParameter("num1");
// String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(cal.getNum1())+Integer.valueOf(cal.getNum2()));
// req.getRequestDispatcher("calRes.jsp").forward(req, resp);
return "calRes";
}
public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String num1 = req.getParameter("num1");
// String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(cal.getNum1())-Integer.valueOf(cal.getNum2()));
// req.getRequestDispatcher("calRes.jsp").forward(req, resp);
return "calRes";
}
public String chen(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String num1 = req.getParameter("num1");
// String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(cal.getNum1())*Integer.valueOf(cal.getNum2()));
// req.getRequestDispatcher("calRes.jsp").forward(req, resp);
return "calRes";
}
public String chu(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String num1 = req.getParameter("num1");
// String num2 = req.getParameter("num2");
req.setAttribute("res", Integer.valueOf(cal.getNum1())/Integer.valueOf(cal.getNum2()));
// req.getRequestDispatcher("calRes.jsp").forward(req, resp);
return "calRes";
}
@Override
public Cal getMoadel() {
return cal;
}
}
通過這個對象進行指派，一開始對象裡肯定是沒值的，那麼怎麼給這個對象先指派呢？可以通過Dispatchersevlet來指派：
if(action instanceof ModelDriven) {
ModelDriven Modeldriven = (ModelDriven)action;
//獲得對象
Object model = Modeldriven.getMoadel();
// Map<String, String[]> map = req.getParameterMap();
// for(Map.Entry<String, String[]> entry : map.entrySet()) {
// //可以擷取到類對應的屬性bname，擷取到類所對應的屬性值；
// }
//将所有的參數自動封裝到實體類T中
BeanUtils.populate(model, req.getParameterMap());
}
5，使得架構的配置檔案可變
在原先的init（）中，configMode = ConfigModelFactory.newInstance();是寫死的，不友善更換XML檔案，所有這樣也是可以加工加強的：
在加工廠中，定義兩個方法即可：
一個有參一個無參，無參調用有參
public class ConfigModelFactory {
private ConfigModelFactory() {
}
private static ConfigModel configModel = null;
public static ConfigModel newInstance() throws Exception {
return newInstance("config.xml");
}
/**
* 工廠模式建立config模組化對象
*
* @param path
* @return
* @throws Exception
*/
public static ConfigModel newInstance(String path) throws Exception {
if (null != configModel) {
return configModel;
}
ConfigModel configModel = new ConfigModel();
InputStream is = ConfigModelFactory.class.getResourceAsStream(path);
SAXReader saxReader = new SAXReader();
Document doc = saxReader.read(is);
List<Element> actionEleList = doc.selectNodes("/config/action");
ActionModel actionModel = null;
ForwardModel forwardModel = null;
for (Element actionEle : actionEleList) {
actionModel = new ActionModel();
actionModel.setPath(actionEle.attributeValue("path"));
actionModel.setType(actionEle.attributeValue("type"));
List<Element> forwordEleList = actionEle.selectNodes("forward");
for (Element forwordEle : forwordEleList) {
forwardModel = new ForwardModel();
forwardModel.setName(forwordEle.attributeValue("name"));
forwardModel.setPath(forwordEle.attributeValue("path"));
forwardModel.setRedirect(forwordEle.attributeValue("redirect"));
actionModel.put(forwardModel);
}
configModel.put(actionModel);
}
return configModel;
}
public static void main(String[] args) {
try {
ConfigModel configModel = ConfigModelFactory.newInstance();
ActionModel actionModel = configModel.get("/loginAction");
ForwardModel forwardModel = actionModel.get("failed");
System.out.println(actionModel.getType());
System.out.println(forwardModel.getPath());
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void init() {
try {
//将原有的讀取架構的預設配置檔案轉變成可配置路徑的配置檔案
String xmlPath = this.getInitParameter("xmlPath");
if(xmlPath ==null||"".equals(xmlPath)) {
configMode = ConfigModelFactory.newInstance();
}else {
configMode = ConfigModelFactory.newInstance(xmlPath);
}
} catch (Exception e) {
e.printStackTrace();
}
}
這就是建議的自定義MVC架構，有什麼疑問可以下方留言或者聯系本人。
![關于Maven的Pom.xml報錯的解決辦法[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)