import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
public class CharacterEncodingFilter implements Filter{
    private FilterConfig config;
    private String encoding;
    private boolean enable;
    
    public void destroy() {
        
    }
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain filterChain) throws IOException, ServletException {
        
        if(this.enable){
            request.setCharacterEncoding(encoding);
            response.setCharacterEncoding(encoding); 
        }
        
        filterChain.doFilter(request, response);
        
        
    }
    public void init (FilterConfig config ) throws ServletException {
        this.config = config;
        loadConfigParams();
        
        
    }
    private void loadConfigParams() {
        this.encoding= this.config.getInitParameter("enconding"); 
        String flag = this.config.getInitParameter("enable");
        if(flag.equalsIgnoreCase("true")){
            this.enable = true;
        }else{
            this.enable = false;
        }
        
        
    }
}
 
 
 
web.xml
 
<filter>
    <filter-name>encondingFilter</filter-name>
    <filter-class>com.morning.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>enconding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
    <init-param>
        <param-name>enable</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encondingFilter</filter-name>
    <url-pattern>*.do</url-pattern>
</filter-mapping>