代理模式的相关使用

　本例子主要是处理request编码问题

public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
        final HttpServletRequest request1=(HttpServletRequest) request;
        request.setCharacterEncoding("utf-8");
        //创建代理对象
        HttpServletRequest p=(HttpServletRequest) Proxy.newProxyInstance(request1.getClass().getClassLoader(),
                new Class[]{HttpServletRequest.class}
                ,new InvocationHandler() {

                    public Object invoke(Object proxy, Method method, Object[] args)
                            throws Throwable {
                        Object returnValue=null;
                        String m=method.getName();
                        if("getParameter".equals(m)){
                            //对get方法进行处理
                            String value=request1.getParameter(args[0].toString());
                            String me=request1.getMethod();
                            if("GET".equals(me)){
                                value=new String(value.getBytes("iso8859-1"),"utf-8");
                            }
                            return value;

                        }else{
                            returnValue=method.invoke(request1, args);
                        }
                        return returnValue;
                    }
                });
        System.out.println("过滤器执行");
        chain.doFilter(p, response);
    }