Servlet——使用Filter对提交数据进行转义

电玩女神 2022-05-16 06:12 197阅读 0赞

### 使用包装设计模式对request进行增强 ###

package com.kexin.web.filter;
    
    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.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    import javax.servlet.http.HttpServletResponse;
    
    public class HtmlFilter implements Filter {
        
    
        @Override
        public void destroy() {
            // TODO Auto-generated method stub
    
        }
    
        @Override
        public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain chain)
                throws IOException, ServletException {
            HttpServletRequest request = (HttpServletRequest) arg0;
            HttpServletResponse response = (HttpServletResponse) arg1;
            chain.doFilter(new MyRequest1(request), response);
        }
    
        @Override
        public void init(FilterConfig arg0) throws ServletException {
            // TODO Auto-generated method stub
    
        }
    
    
    }
    class MyRequest1 extends HttpServletRequestWrapper{
        private HttpServletRequest request;
        public MyRequest1(HttpServletRequest request) {
            super(request);
            this.request = request;
        }
        @Override
        public String getParameter(String name) {
            String message = this.request.getParameter(name);
            if (message == null)
                return (null);
            char content[] = new char[message.length()];
            message.getChars(0, message.length(), content, 0);
            StringBuffer result = new StringBuffer(content.length + 50);
            for (int i = 0; i < content.length; i++) {
                switch (content[i]) {
                case '<':
                    result.append("<");
                    break;
                case '>':
                    result.append(">");
                    break;
                case '&':
                    result.append("&");
                    break;
                case '"':
                    result.append(""");
                    break;
                default:
                    result.append(content[i]);
                }
            }
            return (result.toString());
        }
    
    
    }