使用适配器模式解决全局乱码

package com.book.filter;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;

/**
 * DESCRIPTION:${DESCRIPTION}
 * User: liwei
 * DateTime: 2015/10/17:18:50
 */
public class GlobalEncodingFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        response.setContentType("text/html;charset=utf-8");
        request = new MyRequest(request);//
        filterChain.doFilter(request, response);
    }

    @Override
    public void destroy() {

    }

}

class MyRequest extends HttpServletRequestWrapper {

    HttpServletRequest request;

    public MyRequest(HttpServletRequest request) {
        super(request);
        this.request = request;
    }

    @Override
    public String getParameter(String name) {
        if(name!=null){
            String[] values = getParameterMap().get(name);
            return values[0];
        }
       return null;
    }

    @Override
    public String[] getParameterValues(String name) {
        if(name!=null){
            return getParameterMap().get(name);
        }
       return null;
    }

    private boolean flag = true;

    @Override
    public Map<String, String[]> getParameterMap() {
        Map<String, String[]> map = request.getParameterMap();
        if (flag) {
            for (Map.Entry<String, String[]> m : map.entrySet()) {
                String values[] = m.getValue();
                for (int i = 0; i < values.length; i++) {
                    try {
                        values[i] = new String(values[i].getBytes("iso-8859-1"), "UTF-8");
                    } catch (UnsupportedEncodingException e) {
                        e.printStackTrace();
                    }
                }
            }
            flag = false;
        }

        return map;
    }
}