基于URL的契约式简易MVC框架

一直以来对0配置的mvc框架很感兴趣。

最近，突发奇想，想试验一下如何利用url来实现契约式的mvc零配置框架。

首先，我们以一个普通的url为例。

"http://ipaddress：prot/project_name/business_name/moudle_name/action_name/"

我们假定从business_name开始我们对应的是java中的类包，moudle_name我们对应成 相应业务的对象名称。

而action_name则是 这个对象中的方法名称。

上面是我们假定的规则。

然后我们可以通过reflect可以找到这个请求相关的方法。这样就可以不同过配置文件来配置相关信息。

同事，我们在定义相对应的annotation来为操作成功失败后做跳转。

以上就是一个大概的思路。现在给大家看看相应的代码。

 

 

首先是我们的web。xml文件

<?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.4"
     xmlns="http://java.sun.com/xml/ns/j2ee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
     http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
     <servlet>
     <servlet-name>action</servlet-name>
     <servlet-class>com.pig.hub.dev.frameWork.action.ActionServlet</servlet-class>
     <init-param>
     <param-name>filename</param-name>
     <param-value>pig.web</param-value>
     </init-param>
      <load-on-startup>0</load-on-startup>
   </servlet>
   <servlet-mapping>
     <servlet-name>action</servlet-name>
     <url-pattern>*.pig</url-pattern>
   </servlet-mapping>
   <welcome-file-list>
     <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
 </web-app>

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>com.pig.hub.dev.frameWork.action.ActionServlet</servlet-class>
    <init-param>
    <param-name>filename</param-name>
    <param-value>pig.web</param-value>
    </init-param>
     <load-on-startup>0</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.pig</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

 其中定义了com.pig.hub.dev.frameWork.action.ActionServlet来去拦截所有的请求（。pig）。filename这个属性是为了给出系统中相应的完成的包名。

 

下面是ActionServlet相应的java代码

import com.pig.hub.dev.frameWork.action.exception.MakeUriException;

 /**
 * @author
 */
 public abstract class AbActionServlet extends HttpServlet implements
        BasicActionServlet {

     /**
     *
     */
     private static final long serialVersionUID = 7911661010594064823L;

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         try {
            doWork(request, response);
         } catch (MakeUriException e) {
        }
    }

     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         try {
            doWork(request, response);
         } catch (MakeUriException e) {
        }
    }

     /**
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     * @see com.pig.hub.dev.frameWork.action.BasicActionServlet#doWork(javax.servlet.http.HttpServletRequest,
     *      javax.servlet.http.HttpServletResponse)
     */
     public abstract void doWork(HttpServletRequest request,
             HttpServletResponse response) throws ServletException, IOException,
            MakeUriException;
}


---------------------------------------------------------

import com.pig.hub.dev.frameWork.action.exception.MakeUriException;

/**
 * @author 
 */
public abstract class AbActionServlet extends HttpServlet implements
		BasicActionServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 7911661010594064823L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			doWork(request, response);
		} catch (MakeUriException e) {
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			doWork(request, response);
		} catch (MakeUriException e) {
		}
	}

	/**
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 * @see com.pig.hub.dev.frameWork.action.BasicActionServlet#doWork(javax.servlet.http.HttpServletRequest,
	 *      javax.servlet.http.HttpServletResponse)
	 */
	public abstract void doWork(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException,
			MakeUriException;
}


---------------------------------------------------------

package com.pig.hub.dev.frameWork.action;

 import java.io.IOException;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.pig.hub.dev.frameWork.action.exception.MakeUriException;

 /**
 *
 */
 public interface BasicActionServlet {
     /**
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     * @throws MakeUriException
     */
     public void  doWork(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException,MakeUriException;
}
-------------------------------------------------------

package com.pig.hub.dev.frameWork.action;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.pig.hub.dev.frameWork.action.exception.MakeUriException;

/**
 * 
 */
public interface BasicActionServlet {
	/**
	 * @param request
	 * @param response
	 * @throws ServletException
	 * @throws IOException
	 * @throws MakeUriException
	 */
	public void  doWork(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException,MakeUriException;
}
-------------------------------------------------------

package com.pig.hub.dev.frameWork.action;

 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.HashMap;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.pig.hub.dev.frameWork.action.config.MethodBean;
 import com.pig.hub.dev.frameWork.action.exception.MakeUriException;
 import com.pig.hub.dev.frameWork.action.exception.MappingException;
 import com.pig.hub.dev.frameWork.action.exception.MethodException;

 public class ActionServlet extends AbActionServlet implements
        BasicActionServlet {

     /**
     *
     */
     private static final long serialVersionUID = 2848825411739564234L;

     private String fileName;

     public void init() throws ServletException {
         fileName = this.getInitParameter("filename");
    }
     @SuppressWarnings("unchecked")
     public void doWork(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException, MakeUriException {

        String s[] = BusinessConfig.makeUri(request);

         String errorMessage="";
         HashMap map = new HashMap();
         if (s.length > 2)
             throw new MakeUriException();

         try {
            MethodBean mBean = BusinessConfig.makeConfig(s, fileName);
            Method m = mBean.getM();
            Class c = mBean.getC();
            m.invoke(c.newInstance(), request, response);
            map = MappingUtil.makeHashMap(m);
             request.getRequestDispatcher((String) map.get("success")).forward(
                    request, response);

         } catch (SecurityException e) {
             errorMessage = "someting";

         } catch (ClassNotFoundException e1) {
             errorMessage = "someting";
         } catch (MethodException e2) {
             errorMessage = "someting";
         } catch (NoSuchMethodException e3) {
             errorMessage = "someting";
         } catch (IllegalArgumentException e4) {
             errorMessage = "someting";
         } catch (IllegalAccessException e5) {
             errorMessage = "someting";
         } catch (InvocationTargetException e6) {
             errorMessage = "someting";
         } catch (InstantiationException e) {
             errorMessage = "someting";
         } catch (MappingException e) {
             errorMessage = "someting";
         } finally {
             if (!errorMessage.equals(""))
                 request.getRequestDispatcher((String) map.get("fail")).forward(
                        request, response);

        }
    }

}

package com.pig.hub.dev.frameWork.action;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.pig.hub.dev.frameWork.action.config.MethodBean;
import com.pig.hub.dev.frameWork.action.exception.MakeUriException;
import com.pig.hub.dev.frameWork.action.exception.MappingException;
import com.pig.hub.dev.frameWork.action.exception.MethodException;

public class ActionServlet extends AbActionServlet implements
		BasicActionServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 2848825411739564234L;

	private String fileName;

	public void init() throws ServletException {
		fileName = this.getInitParameter("filename");
	}
	@SuppressWarnings("unchecked")
	public void doWork(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException, MakeUriException {

		String s[] = BusinessConfig.makeUri(request);
		
		String errorMessage="";
		HashMap map = new HashMap();
		if (s.length > 2)
			throw new MakeUriException();

		try {
			MethodBean mBean = BusinessConfig.makeConfig(s, fileName);
			Method m = mBean.getM();
			Class c = mBean.getC();
			m.invoke(c.newInstance(), request, response);
			map = MappingUtil.makeHashMap(m);
			request.getRequestDispatcher((String) map.get("success")).forward(
					request, response);

		} catch (SecurityException e) {
			errorMessage = "someting";

		} catch (ClassNotFoundException e1) {
			errorMessage = "someting";
		} catch (MethodException e2) {
			errorMessage = "someting";
		} catch (NoSuchMethodException e3) {
			errorMessage = "someting";
		} catch (IllegalArgumentException e4) {
			errorMessage = "someting";
		} catch (IllegalAccessException e5) {
			errorMessage = "someting";
		} catch (InvocationTargetException e6) {
			errorMessage = "someting";
		} catch (InstantiationException e) {
			errorMessage = "someting";
		} catch (MappingException e) {
			errorMessage = "someting";
		} finally {
			if (!errorMessage.equals(""))
				request.getRequestDispatcher((String) map.get("fail")).forward(
						request, response);
			
		}
	}

}

以上基本有一个抽象类一个接口一个实现构成，其实只是用到了简单的模板方法。

其中，String s[] = BusinessConfig.makeUri(request);是为了得到url中相应的业务名对象名以及方法名称。

然后通过MethodBean mBean = BusinessConfig.makeConfig(s, fileName）来构建一个自定义的方法对象。

package com.pig.hub.dev.frameWork.action.config;

 import java.lang.reflect.Method;

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.pig.hub.dev.frameWork.action.exception.MethodException;

 public class MethodBean implements java.io.Serializable {
     /**
     *
     */
     private static final long serialVersionUID = -5753278542873561978L;
     private Class c;
     private Method m;
     private String name;


     public Class getC() {
         return c;
    }

     public void setC(Class c) {
         this.c = c;
    }

     public Method getM() {
         return m;
    }

     public void setM() throws MethodException, ClassNotFoundException,
            SecurityException, NoSuchMethodException {
         if (name == null || name.equals(""))
             throw new MethodException();
         if (c == null)
             throw new ClassNotFoundException();
         m = c.getDeclaredMethod(name, HttpServletRequest.class,
                 HttpServletResponse.class);
    }

     public String getName() {
         return name;
    }

     public void setName(String name) {
         this.name = name;
    }
}

package com.pig.hub.dev.frameWork.action.config;

import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.pig.hub.dev.frameWork.action.exception.MethodException;

public class MethodBean implements java.io.Serializable {
	/**
	 * 
	 */
	private static final long serialVersionUID = -5753278542873561978L;
	private Class c;
	private Method m;
	private String name;
	

	public Class getC() {
		return c;
	}

	public void setC(Class c) {
		this.c = c;
	}

	public Method getM() {
		return m;
	}

	public void setM() throws MethodException, ClassNotFoundException,
			SecurityException, NoSuchMethodException {
		if (name == null || name.equals(""))
			throw new MethodException();
		if (c == null)
			throw new ClassNotFoundException();
		m = c.getDeclaredMethod(name, HttpServletRequest.class,
				HttpServletResponse.class);
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

 通过 m = c.getDeclaredMethod(name, HttpServletRequest.class,  HttpServletResponse.class);得到url对应的方法对象。

下面就简单了

m.invoke(c.newInstance(), request, response);

执行而已。

 

现在通过契约式的url可以访问到相应的对象了。那么还差一个如何跳转。

首先我们自定义一个annotation

package com.pig.hub.dev.frameWork.annotation;

 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;

 /**
 *
 */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 public @interface MappingConfig {

    String success();

    String fail();

    String exception();

}

package com.pig.hub.dev.frameWork.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MappingConfig {

	String success();

	String fail();

	String exception();

}

 其中有三个属性，success fail exception分别指在成功后跳转的地方或者失败后跳转的。。。

下面是在实际对象中如何使用这三个对象。

public class aa {
     @MappingConfig(success="../index.jsp",fail="",exception="")
     public void bb(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         System.out.print("test------------");
         request.setAttribute("123", "成功了");
    }

}

public class aa {
	@MappingConfig(success="../index.jsp",fail="",exception="")
	public void bb(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		System.out.print("test------------");
		request.setAttribute("123", "成功了");
	}

}

 然后通过

package com.pig.hub.dev.frameWork.action;

 import java.lang.reflect.Method;
 import java.util.HashMap;

 import com.pig.hub.dev.frameWork.action.exception.MappingException;
 import com.pig.hub.dev.frameWork.annotation.MappingConfig;

 public class MappingUtil {
     @SuppressWarnings("unchecked")
     public static HashMap makeHashMap(Method m) throws MappingException {
         MappingConfig an = m.getAnnotation(MappingConfig.class);

         if (an == null)
             throw new MappingException();
         HashMap map = new HashMap();

         map.put("success", an.success());
         map.put("fail", an.fail());
         map.put("exception", an.exception());
         return map;

    }

}

package com.pig.hub.dev.frameWork.action;

import java.lang.reflect.Method;
import java.util.HashMap;

import com.pig.hub.dev.frameWork.action.exception.MappingException;
import com.pig.hub.dev.frameWork.annotation.MappingConfig;

public class MappingUtil {
	@SuppressWarnings("unchecked")
	public static HashMap makeHashMap(Method m) throws MappingException {
		MappingConfig an = m.getAnnotation(MappingConfig.class);

		if (an == null)
			throw new MappingException();
		HashMap map = new HashMap();

		map.put("success", an.success());
		map.put("fail", an.fail());
		map.put("exception", an.exception());
		return map;

	}

}

 

得到要执行的方法上的annotation然后将他属性放入一个hashmap中。

下面就是跳转了（成功的）

   request.getRequestDispatcher((String) map.get("success")).forward(
     request, response);

 

这样就完成了一个基于url契约的零配置mvc的实现。

呵呵，实在有点简单，问题也很多。

写这个东西的目的其实在于学习一下java的基本知识。现在大家没事干就说这样那样的框架，我想不如自己来试着如何实现。通过自己来实现，可以明白好多东西，然后在去用那写框架我想会更加得心应手。

以上纯属功能上的实现，问题很多很多，例如在actionservlet中有一大堆的异常，这样写出来很别扭，其中还有自己定义的异常。

欢迎大家给我提出建议。