java web filter handles messy code

When we read the foreground data on servlet pages, we often have the problem of garbled code

You use it in servlet every time

String encoding="utf-8"; 
request.setCharacterEncoding(enconding); 
response.setCharacterEncoding(enconding); 

The conversion to code can be cumbersome

So using filters we can avoid this duplication of effort

web. xml configuration

<filter> 
 <filter-name>encodingFilter</filter-name> 
 <filter-class>com.scx.filter.Filter</filter-class> 
 <!--  Initialization parameter  --> 
 <init-param> 
  <param-name>encoding</param-name> 
  <param-value>utf-8</param-value> 
 </init-param> 
 </filter> 
 <!-- filter The mapping relationship  --> 
 <filter-mapping> 
 <filter-name>encodingFilter</filter-name> 
 <url-pattern>/*</url-pattern> 
 </filter-mapping> 

Filter

package com.scx.filter; 
import java.io.IOException; 
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 Filter implements javax.servlet.Filter{ 
  // Read the filter configuration file  
  private FilterConfig config; 
  public void destroy() { 
    // TODO Auto-generated method stub 
  } 
  public void doFilter(ServletRequest arg0, ServletResponse arg1, 
      FilterChain chain) throws IOException, ServletException { 
    // TODO Auto-generated method stub 
    HttpServletRequest request=(HttpServletRequest) arg0; 
    HttpServletResponse response=(HttpServletResponse) arg1; 
    String encoding=config.getInitParameter("encoding"); 
    if(encoding==null||"".equals(encoding)){ 
      encoding="utf-8"; 
    } 
    request.setCharacterEncoding(encoding); 
    response.setCharacterEncoding(encoding); 
    chain.doFilter(request, response); 
  } 
  public void init(FilterConfig arg0) throws ServletException { 
    // TODO Auto-generated method stub 
    config=arg0; 
  } 
} 

In this way, the data read in servlet will not appear disorderly code situation