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;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SetCharacterEncodingFilter implements Filter {

private FilterConfig filterConfig;

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

public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request;
HttpServletResponse response;
try {
request = (HttpServletRequest) req;
response = (HttpServletResponse) res;
} catch (ClassCastException e) {
throw new ServletException("non-HTTP request or response");
}

String encoding = filterConfig.getInitParameter("encoding");
if(encoding==null){
encoding = "UTF-8";
}

//POST:
request.setCharacterEncoding(encoding);
response.setCharacterEncoding(encoding);
response.setContentType("text/html;charset="+encoding);
chain.doFilter(request, response);
}

public void destroy() {

}

}

REq,RES编码设置