六、自定义MVC

本篇博文博主就用纯代码展示啦

用MVC登录的例子

1.首先得有两个界面

login.jsp（登录的页面）

  <body>
        <h1>登录</h1>
        <form action="login.do" method="post">
              用户名:<input type="text" name="uname"/><br/>
              密码:<input type="password" name="upass"/><br/>
              <input type="submit" value="登录"/><br/>
        </form>
        <%-- 浏览器查看：    http://localhost:8080/项目名/login.jsp --%>
  </body>

index.jsp（登录成功的页面）

   ......
   </head>
  
   <body>
       登录成功！<br>
   </body>

2.写util包的DBHelper类

package com.zking.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;

public class DBHelper {
   
	   public static Connection getConn(){
		      try {
				    Context context=new InitialContext();
				    Context contextJava=(Context)context.lookup("java:comp/env");
				    DataSource ds=(DataSource)contextJava.lookup("jdbc/UsersDB");
				    return ds.getConnection();
			  } catch (Exception e) {
				   e.printStackTrace();
			  }
			  return null;
	   }
	
	   public static void close(Connection conn,PreparedStatement ps,ResultSet rs){
		      try {
				  if(conn!=null && !conn.isClosed()){
					   conn.close();
				  }
				  if(ps!=null){
					   ps.close();
				  }
				  if(rs!=null){
					   rs.close();
				  }
			 } catch (Exception e) {
				  e.printStackTrace();
			 }
	   }
	
	
}

3.写entity包的实体类

package com.zking.entity;

public class Users {
       private int uid;
       private String uname;
       private String upass;
	public Users() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Users(String uname, String upass) {
		super();
		this.uname = uname;
		this.upass = upass;
	}
	public Users(int uid, String uname, String upass) {
		super();
		this.uid = uid;
		this.uname = uname;
		this.upass = upass;
	}
	public int getUid() {
		return uid;
	}
	public void setUid(int uid) {
		this.uid = uid;
	}
	public String getUname() {
		return uname;
	}
	public void setUname(String uname) {
		this.uname = uname;
	}
	public String getUpass() {
		return upass;
	}
	public void setUpass(String upass) {
		this.upass = upass;
	}
	@Override
	public String toString() {
		return "Users [uid=" + uid + ", uname=" + uname + ", upass=" + upass
				+ "]";
	}
       
}

4.写Dao包

package com.zking.dao;

import com.zking.entity.Users;

public interface UsersDao {

	   public boolean Login(Users u);
	   
}

package com.zking.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.zking.entity.Users;
import com.zking.util.DBHelper;

public class UsersDaoImp implements UsersDao {

	public boolean Login(Users u) {
		   boolean b=false;
		   Connection conn=DBHelper.getConn();
		   PreparedStatement ps=null;
		   ResultSet rs=null;
		   try {
			   ps=conn.prepareStatement("select * from Users where uname=? and upass=?");
			   ps.setString(1, u.getUname());
			   ps.setString(2, u.getUpass());
			   rs=ps.executeQuery();
			   return b=rs.next();
		} catch (Exception e) {
			 e.printStackTrace();
		}finally{
			 DBHelper.close(conn, ps, rs);
		}
		return b;
	}

}

5.写Biz包

package com.zking.biz;

import com.zking.entity.Users;

public interface UsersBiz {
   
	   public boolean Login(Users u);
}

package com.zking.biz;

import com.zking.dao.UsersDao;
import com.zking.dao.UsersDaoImp;
import com.zking.entity.Users;

public class UsersBizImp implements UsersBiz {

	private UsersDao ud;

	public UsersBizImp() {
		   ud = new UsersDaoImp();
	}

	public boolean Login(Users u) {
		return ud.Login(u);
	}

}

6.定义个servlet（TotalServlet）控制所有的*.do请求

package com.zking.servlet;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Reader;
import java.util.Properties;

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

public class TotalServlet extends HttpServlet{
	
	@Override
	public void init(ServletConfig config) throws ServletException {
		try {
			Properties pro=new Properties();//加载配置文件config.properties
			Properties proObject=new Properties();
			String path=config.getServletContext().getRealPath("/");//1获取服务器的路径
			FileInputStream fis=new FileInputStream(path+"WEB-INF/config.properties");
			pro.load(fis);
			config.getServletContext().setAttribute("properties", pro);////将properties存放到application中
			config.getServletContext().setAttribute("propertiesObject", proObject);
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		    String uri=req.getRequestURI();//获取请求路径
		    //截取
		    int lastXie=uri.lastIndexOf("/");//获取最后一个斜杠的位置
		    int lastPoint=uri.lastIndexOf(".");//获取最后一个点的位置
		    uri=uri.substring(lastXie+1, lastPoint);
		    System.out.println("请求路径："+uri);
		    //从application中获取properties
		    Properties pro=(Properties) req.getSession().getServletContext().getAttribute("properties");
		    //根据键获取值
		    String className=pro.getProperty(uri);
		    System.out.println("获取到相对应的全限定名为:"+className);
		    Properties proObject=(Properties) req.getSession().getServletContext().getAttribute("propertiesObject");
		    TotalDo total=(TotalDo) proObject.get(className);
		    //根据类的全限定名 来 实例化 该对象
		   try {
			   if(total==null){//初始化对象
				   total=(TotalDo)Class.forName(className).newInstance();
				   proObject.put(className, total);//必须存放
			   }
			   total.execute(req,resp);
		  } catch (Exception e) {
			   e.printStackTrace();
		  }
	}

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doPost(req, resp);
	}
	
	
}

7.新建一个接口(TotalDo)，声明方法execute();将所有的实现类继承action接口

package com.zking.servlet;

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

/**
 * 所有servlet的接口
 */
public interface TotalDo {
	   
       public void execute(HttpServletRequest req, HttpServletResponse resp);
}

8.登录的业务逻辑

package com.zking.servlet;

import java.io.IOException;

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

import com.zking.biz.UsersBizImp;
import com.zking.entity.Users;

public class LoginDo implements TotalDo{

	public void execute(HttpServletRequest req, HttpServletResponse resp) {
		   resp.setContentType("text/html; charset=UTF-8");
		
		   String uname=req.getParameter("uname");
		   String upass=req.getParameter("upass");
		   
		   UsersBizImp ubi=new UsersBizImp();
		   boolean b=ubi.Login(new Users(uname,upass));
		   if(b){
			     System.out.println("登录成功！");
			     try {
					req.getRequestDispatcher("index.jsp").forward(req, resp);
				} catch (ServletException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}
		   }else{
			     System.out.println("登录失败！");
			     try {
					resp.sendRedirect("login.jsp");
				} catch (IOException e) {
					e.printStackTrace();
				}
		   }
	}

}

9.在WEB-INF目录下写config.properties

login=com.zking.servlet.LoginDo

10.配置web.xml

  <!-- 配置总的Servlet -->
  <servlet>
  	<servlet-name>totalServlet</servlet-name>
  	<servlet-class>com.zking.servlet.TotalServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>totalServlet</servlet-name>
	<url-pattern>*.do</url-pattern>  
  </servlet-mapping>

到此，一个简单的用mvc框架进行登录的例子就写好了。