完整的字符编码过滤器

   字符过滤器

package com.pdworld.web.filter;

import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;

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.HttpServletResponse;

public class Encode implements Filter {

	private String encode;
	private String decode;
	public void destroy() {
		
	}
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req=(HttpServletRequest)request;
		HttpServletResponse resp=(HttpServletResponse)response;
		
		//获得请求方式
		String method=req.getMethod();
		//post 请求可直接设置编码方式
		if("post".equalsIgnoreCase(method)){
			System.out.println("进行编码!");
			request.setCharacterEncoding("GBK");
			response.setCharacterEncoding("GBK");
		}else{
			//get 请求
			//从请求中获得所有参数的键值对
			Map params=req.getParameterMap();
			//获得所有参数的值
			Collection c=params.values();
			//迭代出每一个参数
			for(Iterator it=c.iterator();it.hasNext();){
				String[] values=(String[])it.next();
				//对每一个字符进行重新的编码解码
				for(int i=0;i<values.length;i++){
					values[i]=new String(values[i].getBytes(encode),decode);
				}
			}
			//将回复的编码设置为utf-8
			response.setCharacterEncoding("GBK");
		}
		//将请求传递到下一个环节
		chain.doFilter(request, response);
	}

	public void init(FilterConfig config) throws ServletException {
		encode=config.getInitParameter("encode");
		decode=config.getInitParameter("decode");
          
	}

}