前言

在之前已经完成了一个自定义mvc模式
此次就是对上一个的补充与增强。

这是上次的图解、

重点：通过XML对自定义mvc框架进行增强

---

mvc之xml配置相应实现类

我们之前是用map集合来进行存储一个类的信息。

这样是有弊端的：比如你想添加一个东西的时候，必定要对这个集合的内容进行修改。

但是我们可以用到xml文件来对应每一个类，只需要修改xml文件就可以动态调用到某个类

现在的init()方法：

public void init() {
		config = configModelFactory.build();//调用默认的xml文件
}

可以用doPost获得

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	init();//使得map里有值
	String requestURI = req.getRequestURI(); //获取请求的路径
	System.out.println("截取前："+requestURI);
	
	String url = requestURI.substring(requestURI.lastIndexOf("/"), requestURI.lastIndexOf("."));//截取
	System.out.println("截取后："+url);
	
	
	actionModel actionModel = config.pop(url);
	if(actionModel==null) {
		throw new RuntimeException("你没有配置相关的action");
	}
	action action = (action)Class.forName(actionModel.getType()).newInstance();//实列化xml中type里面的内容地址
	String code = action.execute(req, resp);
}

xml文件的配置

<config>

	<action path="/add" type="com.liwangwang.web.addAction">//这个的type就是一个类的路径
		<forward name="calres" path="/calres.jsp" redirect="false" />
	</action>
	<action path="/del" type="com.liwangwang.web.delAction">
		<forward name="calres" path="/calres.jsp" redirect="false" />
	</action>

</config>

---

mvc之xml提供返回路径

在方法中有这样的req.getRequestDispatcher("calres.jsp").forward(req, resp);可能需要多次运用，所以可以在从xml中获取到返回的路径

所以简单的调用节点.

public String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String num1 = req.getParameter("num1");
		String num2 = req.getParameter("num2");
		req.setAttribute("res", Integer.parseInt(num1)+Integer.parseInt(num2));
		//req.getRequestDispatcher("calres.jsp").forward(req, resp);//我们要优化这行代码
		
		return "calres";
	}

实现

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		init();//使得map里有值
		String requestURI = req.getRequestURI(); //获取请求的路径
		System.out.println("截取前："+requestURI);
		
		String url = requestURI.substring(requestURI.lastIndexOf("/"), requestURI.lastIndexOf("."));//截取
		System.out.println("截取后："+url);
		
		
		actionModel actionModel = config.pop(url);
		if(actionModel==null) {
			throw new RuntimeException("你没有配置相关的action");
		}
		
		try {
			action action = (action)Class.forName(actionModel.getType()).newInstance();//实列化xml中type里面的内容地址
			
			if(action instanceof ModelDirven) {
				ModelDirven modeldirven = (ModelDirven)action;
				Object model = modeldirven.getModel();
				
				BeanUtils.populate(model, req.getParameterMap());
			}
			
			String code = action.execute(req, resp);//获取返回路径的名字
			forwardModel forwardModel = actionModel.pop(code);
			
			if(forwardModel==null) {
				throw new RuntimeException("你没有配置对应子控制器action的处理方式");
			}
			
			String jsppath = forwardModel.getPath();//获取返回的路径
			
			if(forwardModel.isRedirect()) {//判断是否要重定向
				resp.sendRedirect(req.getContextPath()+jsppath);
			}
			else  {//判断是否要转发
				req.getRequestDispatcher(req.getContextPath()+jsppath).forward(req, resp);
			}
			
			
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		}
	}

mvc之一个超类自动调用方法（需传method）

我们需要用一个方法来调用相对应的方法。

那么就需要用到了反射的机制。

将其全放入到calAction

public class CalAction extends actionSupper{
	public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
			String num1 = req.getParameter("num1");
			String num2 = req.getParameter("num2");
			req.setAttribute("res", Integer.parseInt(cal.getNum1())+Integer.parseInt(cal.getNum2()));
			
			return "calres";//返回路径的名字
		}
	public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
			String num1 = req.getParameter("num1");
			String num2 = req.getParameter("num2");
			req.setAttribute("res", Integer.parseInt(cal.getNum1())-Integer.parseInt(cal.getNum2()));
			
			return "calres";//返回的路径名字
		}
}

一个超类，

public class actionSupper implements action {


	public final String execute(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String code = null;
		try {
			Method Method = this.getClass().getDeclaredMethod(req.getParameter("method"), HttpServletRequest.class,HttpServletResponse.class);
			Method.setAccessible(true);
			code = (String) Method.invoke(this, req,resp);//调用相对应的方法
			
			
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		}
		
		return code;
	}

}

---

mvc之自动获取参数值

因为如果有多个参数的话就比较麻烦，所以需要优化

比如这行：

String num1 = req.getParameter("num1");
		String num2 = req.getParameter("num2");

创建一个接口

public interface ModelDirven<T>{
	T getModel();
}

然后继承

public class CalAction extends actionSupper implements ModelDirven<Cal> {
	
	private Cal cal =new Cal();
	
	public String add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	
		req.setAttribute("res", Integer.parseInt(cal.getNum1())+Integer.parseInt(cal.getNum2()));
		
		return "calres";
	}
	public String del(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("res", Integer.parseInt(cal.getNum1())-Integer.parseInt(cal.getNum2()));
		
		return "calres";
	}
	
	@Override
	public Cal getModel() {
		
		return cal;
	}
}

mvc之使得导入的xml可选择

大家大概也看到了，在之前init()方法是这样的：

public void init() {
				config = configModelFactory.build();
	}

优化后

public void init() {
		try {
			
			//使得调用指定位置的xml文件
			String xmlpath  = this.getInitParameter("xmlpath");
			if(xmlpath==null||"".equals(xmlpath)) {
				config = configModelFactory.build();
			}
			else {
				config = configModelFactory.build(xmlpath);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		
	}

需要在web.xml中配置

---

总结

在继承和实现的流程中，我还是有点没搞明白

Thanks♪(･ω･)ﾉ希望对大家有所帮助