structs2-使用filter作为控制器的MVC应用

偏执的太偏执、 2022-04-15 05:11 135阅读 0赞

MVC设计模式的概览  
实现MVC（Model -View- Controller(servlet/filter)）  
在index.jsp页面中有超链接跳转到input.jsp，在input.jsp中表单添加数据，提交并显示在details.jsp页面中  
index.jsp页面中：

input.jsp页面中

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
    
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>Insert title here</title>
    </head>
    <body>
    <form action="product-save.action"method="post"></form>
    produceName：<input type="text" name="produceName">
    produceDesc：<input type="text" name="produceDesc">
    producePrice：<input type="text" name="producePrice">
    <input type="submit" value="提交">
    </body>
    </html>

在details.jsp中

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
    <%@ taglib prefix="f"  uri="http://java.sun.com/jsf/core"%>
    <%@ taglib prefix="h"  uri="http://java.sun.com/jsf/html"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>Insert title here</title>
    </head>
    <body>
    productId：${requestScope.product.productId} 
    productName：${requestScope.product.productName} 
    productDesc：${requestScope.product.productDesc} 
    productPrice：${requestScope.product.productPrice} 
    </body>
    </html>

filter类中

package com.guigu.struts;
        
        import java.io.IOException;
        import javax.servlet.Filter;
        import javax.servlet.FilterChain;
        import javax.servlet.FilterConfig;
        import javax.servlet.ServletException;
        import javax.servlet.ServletRequest;
        import javax.servlet.ServletResponse;
        import javax.servlet.annotation.WebFilter;
        
        /**
         * Servlet Filter implementation class FilterDispatcher
         */
        @WebFilter({ "/FilterDispatcher", "*.action" })
        public class FilterDispatcher implements Filter {
        
            
        	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        		HttpServletRequest request=(HttpServletRequest)request;
        		String servlePath=request.getServletPath();
        		String path=null;
        		//2.判断servlePath，若其等于"/product-input.action"，则转发到"/WEB-INF/pages/input.jsp"
        		if("/product-input.action".equals(servlePath))
        			path="/WEB-INF/pages/input.jsp";
        		//3.若其等于/product-save.action，则
        		if("/product-save.action".equals(servlePath)) {
        			String productName=request.getParameter("productName");
        			String productDesc=request.getParameter("productDesc");
        			String productPrice=request.getParameter("productPrice");
        		
        		//3.1获取请求信息封装为一个product对象
        		Product product=new Product (null,productName,productDesc, productPrice);
        		//3.2执行保存操作
        		System.out.println("保存操作");
        		product.setProductId(122);
        		//3.4把product对象保存在request中
        		request.setAttribute("product",product);
        		path="/WEB-INF/pages/details.jsp";}
        		if(path!=null)
        		{request.getRequestDispatcher(path).forword(request,response);}
        		
        		chain.doFilter(request, response);
        	}
    	/**
    	 * @see Filter#init(FilterConfig)
    	 */
    	public void init(FilterConfig fConfig) throws ServletException {
    		// TODO Auto-generated method stub
    	}
    
    }

product类

package com.guigu.struts;
    
    public class Product {
    private Integer productId;
    private String productName;
    private String productDesc;
    private String productPrice;
    public String getProductName() {
    	return productName;
    }
    public void setProductName(String productName) {
    	this.productName = productName;
    }
    public String getProductDesc() {
    	return productDesc;
    }
    public void setProductDesc(String productDesc) {
    	this.productDesc = productDesc;
    }
    public String getProductPrice() {
    	return productPrice;
    }
    public void setProductPrice(String productPrice) {
    	this.productPrice = productPrice;
    }
    
    
    public Product(Integer productId, String productName, String productDesc, String productPrice) {
    	super();
    	this.productId = productId;
    	this.productName = productName;
    	this.productDesc = productDesc;
    	this.productPrice = productPrice;
    }
    public Integer getProductId() {
    	return productId;
    }
    public void setProductId(Integer productId) {
    	this.productId = productId;
    }
    public Product() {
    	super();
    	// TODO Auto-generated constructor stub
    }
    
    }

使用Filter作为控制器好处：  
使用一个过滤器作为控制器，可以方便应用程序中对所有资源（包括静态资源）进行控制访问

servlet 和filter 对比  
1.servlet 能做的filter都能完成  
2.filter一个有filterChain,这个API在servlet没有。