Web--Filter使用装饰器模式解决全站中文乱码问题

古城微笑少年丶 2021-08-13 11:23 317阅读 0赞

#### 使用过滤器完成对中文编码的统一处理问题： ####

表单页面：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>表单</title>
    </head>
    <body>
        <form action="/JavaEEDemo/encoding" method="get">
            用户名:<input type="text" name="username"><br/>
            密  码:<input type="password" name="password"><br/>
            <input type="submit" value="提交">
    
        </form>
    </body>
    </html>

处理表单的Servlet：

public class EncodingServlet extends HttpServlet { 
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
            String username = request.getParameter("username");
            String password = request.getParameter("password");
    
            System.out.println(username + "：" + password);
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
            doPost(request, response);
        }
    }

过滤器：

package pers.zhang.filter;
    
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    
    /** * @author zhang * @date 2019/9/21 - 15:55 */
    public class EncodingFilter implements Filter { 
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            //被增强的对象
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            //增强对象
            EnhanceRequest enhanceRequest = new EnhanceRequest(request);
    
    
            filterChain.doFilter(enhanceRequest, servletResponse);
        }
    
        @Override
        public void destroy() { 
    
        }
    }
    
    class EnhanceRequest extends HttpServletRequestWrapper { 
    
        private HttpServletRequest request;
    
        public EnhanceRequest(HttpServletRequest request) { 
            super(request);
            this.request = request;
        }
    
        //对getParaameter增强
        @Override
        public String getParameter(String name) { 
            String parameter = request.getParameter(name);//乱码
            try { 
                parameter = new String(parameter.getBytes("iso8859-1"),"UTF-8");
            } catch (UnsupportedEncodingException e) { 
                e.printStackTrace();
            }
            return parameter;
        }
    
    }

配置：

<filter>
            <filter-name>encodingFilter</filter-name>
            <filter-class>pers.zhang.filter.EncodingFilter</filter-class>
        </filter>
        <filter-mapping>
            <filter-name>encodingFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>

测试：  
启动服务器，访问表单页面：  
![在这里插入图片描述][20190921164854775.png]  
点击提交，控制台输出：

张三：123456

[20190921164854775.png]: /images/20210813/13b274de4ab74c09addc347dddc2dde4.png