字符编码过滤器EncodingFilter

package com.lzcc.mvc.web.filter;

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

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.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.http.HttpServletRequest;
@WebFilter(filterName="encodingFilter",urlPatterns="/*",initParams={@WebInitParam(description="字符编码",name="charSet",value="UTF-8")})
public class EncodingFilter implements Filter{

 private String charSet;
 
 @Override
 public void destroy() {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void doFilter(ServletRequest req, ServletResponse resp,
   FilterChain chain) throws IOException, ServletException {
  // TODO Auto-generated method stub
  
  HttpServletRequest request = (HttpServletRequest)req;
  
  // 判断用户的请求类型
  if(request.getMethod().equalsIgnoreCase("POST")){// 如果请求是POST
   req.setCharacterEncoding(this.charSet);// 设置统一编码
  }else{// get请求
   
   Map<String, String[]> maps = req.getParameterMap();
   
   Iterator<Entry<String, String[]>> iter =  maps.entrySet().iterator();
   
   while(iter.hasNext()){
    
    Entry<String, String[]> map = iter.next();
    
    String[] values = map.getValue();
    
    for (int i = 0; i < values.length; i++) {
     values[i] = new String(values[i].getBytes("ISO-8859-1"), this.charSet);
    }
   }
   
  }
  
  chain.doFilter(req, resp);// 将请求继续传递
 }

 @Override
 public void init(FilterConfig config) throws ServletException {
  // TODO Auto-generated method stub
  this.charSet = config.getInitParameter("charSet");
 }
 
}