struts2:使用Filter作为控制器的MVC

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使用Fliter作为控制器，可以方便的在应用程序里对所有资源包括静态资源进行控制访问

以下是一个用Filter作为控制器的例子
程序结构
这里写图片描述

web.xml的配置

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0"     xmlns="http://java.sun.com/xml/ns/javaee"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <filter>    <filter-name>product</filter-name>    <filter-class>com.struts.first.FilterDispatcher</filter-class>  </filter>  <filter-mapping>    <filter-name>product</filter-name>    <url-pattern>*.action</url-pattern>  </filter-mapping>  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

index.jsp

<body>    <a href="product-input.action">product input</a></body>

input.jsp

<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>

details.jsp

<body>    ProductName:${requestScope.product.productId}<br/>    ProductName:${requestScope.product.productName}<br/>    ProductName:${requestScope.product.productDesc}<br/>    ProductName:${requestScope.product.productPrice}<br/>  </body>

FilterDispatcher.java

public class FilterDispatcher implements Filter {    @Override    public void destroy() {}    @Override    public void doFilter(ServletRequest request, ServletResponse response,            FilterChain chain) throws IOException, ServletException {        HttpServletRequest req=(HttpServletRequest)request;        String path=null;        //1.获取servletPath        String servletPath=req.getServletPath();        System.out.println(servletPath);        //2.判断servletPath，若其等于"/product-input.action"则转发到        //  /WEB-INF/pages/input.jsp        if("/product-input.action".equals(servletPath)){            path="/WEB-INF/pages/input.jsp";        }        //3.若其等于"/product-input.action"则转发到/WEB-INF/pages/details.jsp        if("/product-save.action".equals(servletPath)){            //1).获取请求参数            String productName= request.getParameter("productName");            String productDesc= request.getParameter("productDesc");            String productPrice= request.getParameter("productPrice");            //2).把请求信息封装为一个Product对象            Product product =                     new Product(null, productName, productDesc, Double.parseDouble(productPrice));            //3).模拟执行保存操作            System.out.println("save"+product.toString());            product.setProductId(1001);            //4).把Product对象保存到request中.${param.productName}->${requestScope.product.productName}            request.setAttribute("product", product);            path="/WEB-INF/pages/details.jsp";        }        if(path!=null){            request.getRequestDispatcher(path).forward(request, response);            return;//重要。转发完就代表已经给过响应了，该方法就要结束，就不能在执行后面的doFilter了        }        chain.doFilter(request, response);    }    @Override    public void init(FilterConfig config) throws ServletException {}}

Product.java

public class Product {      private Integer productId;    private String productName;    private String productDesc;    private Double productPrice;    public Product(){}    public Product(Integer productId, String productName, String productDesc,            double 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 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 Double getProductPrice() {        return productPrice;    }    public void setProductPrice(Double productPrice) {        this.productPrice = productPrice;    }    @Override    public String toString() {        return "Product [productName=" + productName + ", productDesc="                + productDesc + ", productPrice=" + productPrice + "]";    }}

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