[Java][Servlet] HTTP-POSTのRequestにsetCharacterEncodingするFilter

CharacterEncodingFilter.java

public class CharacterEncodingFilter implements Filter {
  public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain chain) throws IOException, ServletException {
    HttpServletRequest httpReq = (HttpServletRequest) request;
    if ("POST".equalsIgnoreCase(httpReq.getMethod())) {
      request.setCharacterEncoding("Windows-31J");
    }
    chain.doFilter(request, response);
  }
}

web.xml

<filter>
  <filter-name>CharacterEncodingFilter</filter-name>
  <filter-class>sample.CharacterEncodingFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>CharacterEncodingFilter</filter-name>
  <url-pattern>/sample/*</url-pattern>
</filter-mapping>