看了网友Roy的评论，研究了一下用filter来解决Struts中文乱码的问题！

package tutorial.struts.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;

public class SetCharacterEncodingFilter implements Filter {

  protected FilterConfig filterConfig;
  protected String encodingName;
  protected boolean enable;

  public SetCharacterEncodingFilter() {
    this.encodingName = "UTF-8";
    this.enable = false;
  }

  public void init(FilterConfig filterConfig) throws ServletException {
    this.filterConfig = filterConfig;
    loadConfigParams();
  }

  private void loadConfigParams() {
    //encoding     
    this.encodingName = this.filterConfig.getInitParameter("encoding");
    //filter enable flag
    String strIgnoreFlag = this.filterConfig.getInitParameter("enable");
    if (strIgnoreFlag.equalsIgnoreCase("true")) {
      this.enable = true;
    } else {
      this.enable = false;
    }
  }

  public void doFilter(ServletRequest request, ServletResponse response,
                       FilterChain chain) throws IOException, ServletException {
    if(this.enable) {
      request.setCharacterEncoding(this.encodingName);
    }
    chain.doFilter(request, response);
  }

  public void destroy() {
  }
		
}

   Set Character Encoding
   tutorial.struts.filter.SetCharacterEncodingFilter
   
     encoding
     UTF-8
   
   
     enable
     true
   
 
 
   Set Character Encoding
   Action Servlet
 
 
   Set Character Encoding
   Faces Servlet