一个简单的JAVA字符集过滤器实现

package dw05prj.util.filter; 

import javax.servlet.Filter; 
import javax.servlet.FilterConfig; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRequest; 
import javax.servlet.ServletResponse; 
import javax.servlet.FilterChain; 
import java.io.IOException; 

/*页面字符集过滤流*/ 

/* 
在web.xml中配制的例子 
CharEncodingFilterdw05prj.util.filter.CharEncodingFiltercharsetGBKCharEncodingFilter/* 
*/ 

public class CharEncodingFilter implements Filter { 

private String charSet ; 

public void init(FilterConfig parm1) throws ServletException { 
charSet = parm1.getInitParameter("charset") ; 
if (charSet == null && charSet.length()