Strut2_使用Filter作为控制器的MVC应用_${requestscope.product.productid }-优快云博客

本文链接：https://blog.youkuaiyun.com/a2181745/article/details/43935331

在input.jsp页面输入表单信息，details.jsp中显示表单信息。Filter类进行逻辑处理，根据servletPath来执行不同的操作。

input.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'input.jsp' starting page</title>

	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
		<form action="product-save.action" method="post"> 
			ProductName :<input type="text" name="productName"/><br>
			ProductDesc: <input type=" text" name="productDesc"/><br>
			ProductPrice: <input type=" text" name="productPrice"/><br>
			<input type="submit" value="Submit"/>
		</form>
  </body>
</html>

details.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'details.jsp' starting page</title>

	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
		  ProductName :${requestScope.product.productName} <br>  
		  ProductId :${requestScope.product.productId} <br>
		  ProductDesc :${requestScope.product.productDesc} <br>
	      ProductPrice :${requestScope.product.productPrice} <br>
  </body>
</html>

Filter类：

public class FilterDispatcher implements Filter {

	public void destroy() {
		
	}

	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req=(HttpServletRequest) request;
		//1.获取servlet的Path
		String serlvetPath=req.getServletPath();
		System.out.println(serlvetPath);
		String path=null;
		//2.判断servletPath，若等于“product-input.action”则转发到input.jsp
		if("/product-input.action".equals(serlvetPath)){
			path="/WEB-INF/pages/input.jsp";
		}
		//3.若等于save则
	    if("/product-save.action".equals(serlvetPath)){
	    	String productName= request.getParameter("productName");
	    	String productDesc= request.getParameter("productDesc");
	    	String productPrice= request.getParameter("productPrice");
	    	Product product = new Product(null,productName,productDesc,Double.parseDouble(productPrice));
	    	System.out.println("Save:"+ product.getProductName());
	    	product.setProductId(Integer.valueOf(1001));
	    	//将Product保存到 request中
	    	request.setAttribute("product", product);
	    	path="/WEB-INF/pages/details.jsp";
	    }
		if (path != null) {
			request.getRequestDispatcher(path).forward(request, response);
			return;
		}
		chain.doFilter(request, response);
	}

	public void init(FilterConfig arg0) throws ServletException {

	}

}

web.xml配置文件：

<?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">
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <filter>
    <display-name>FilterDispatcher</display-name>
  	<filter-name>FilterDispatcher</filter-name>
  	<filter-class>com.hcx.struts2.helloWorld.FilterDispatcher</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>FilterDispatcher</filter-name>
  	<url-pattern>*.action</url-pattern>
  </filter-mapping>
  
</web-app>

Servlet VS Filter

1.servlet 能做的Filter都能完成

2.Filter 独有FilterChain，这个API在Servlet中不存在，filter能进行拦截