package filters;
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.UnavailableException;

/**
 * <p>Example filter that sets the character encoding to be used in parsing the
 * incoming request, either unconditionally or only if the client did not
 * specify a character encoding. Configuration of this filter is based on
 * the following initialization parameters:</p>
 * <ul>
 * <li><strong>encoding</strong> - The character encoding to be configured
 *   for this request, either conditionally or unconditionally based on
 *   the <code>ignore</code> initialization parameter. This parameter
 *   is required, so there is no default.</li>
 * <li><strong>ignore</strong> - If set to "true", any character encoding
 *   specified by the client is ignored, and the value returned by the
 *   <code>selectEncoding()</code> method is set. If set to "false,
 *   <code>selectEncoding()</code> is called <strong>only</strong> if the
 *   client has not already specified an encoding. By default, this
 *   parameter is set to "true".</li>
 * </ul>
 *
 * <p>Although this filter can be used unchanged, it is also easy to
 * subclass it and make the <code>selectEncoding()</code> method more
 * intelligent about what encoding to choose, based on characteristics of
 * the incoming request (such as the values of the <code>Accept-Language</code>
 * and <code>User-Agent</code> headers, or a value stashed in the current
 * user's session.</p>
 *
 * @author Craig McClanahan
 * @version $Revision: 1.2 $ $Date: 2001/10/17 22:53:19 $
 */

public class SetCharacterEncodingFilter implements Filter {


  // ----------------------------------------------------- Instance Variables


  /**
   * The default character encoding to set for requests that pass through
   * this filter.
   */
  protected String encoding = null;


  /**
   * The filter configuration object we are associated with. If this value
   * is null, this filter instance is not currently configured.
   */
  protected FilterConfig filterConfig = null;


  /**
   * Should a character encoding specified by the client be ignored?
   */
  protected boolean ignore = true;


  // --------------------------------------------------------- Public Methods


  /**
   * Take this filter out of service.
   */
  public void destroy() {

    this.encoding = null;
    this.filterConfig = null;

  }


  /**
   * Select and set (if specified) the character encoding to be used to
   * interpret request parameters for this request.
   *
   * @param request The servlet request we are processing
   * @param result The servlet response we are creating
   * @param chain The filter chain we are processing
   *
   * @exception IOException if an input/output error occurs
   * @exception ServletException if a servlet error occurs
   */
  public void doFilter(ServletRequest request, ServletResponse response,
             FilterChain chain)
    throws IOException, ServletException {

    // Conditionally select and set the character encoding to be used
    if (ignore || (request.getCharacterEncoding() == null)) {
      String encoding = selectEncoding(request);
      if (encoding != null)
        request.setCharacterEncoding(encoding);
    }

    // Pass control on to the next filter
    chain.doFilter(request, response);

  }


  /**
   * Place this filter into service.
   *
   * @param filterConfig The filter configuration object
   */
  public void init(FilterConfig filterConfig) throws ServletException {

    this.filterConfig = filterConfig;
    this.encoding = filterConfig.getInitParameter("encoding");
    String value = filterConfig.getInitParameter("ignore");
    if (value == null)
      this.ignore = true;
    else if (value.equalsIgnoreCase("true"))
      this.ignore = true;
    else if (value.equalsIgnoreCase("yes"))
      this.ignore = true;
    else
      this.ignore = false;

  }


  // ------------------------------------------------------ Protected Methods


  /**
   * Select an appropriate character encoding to be used, based on the
   * characteristics of the current request and/or filter initialization
   * parameters. If no character encoding should be set, return
   * <code>null</code>.
   * <p>
   * The default implementation unconditionally returns the value configured
   * by the <strong>encoding</strong> initialization parameter for this
   * filter.
   *
   * @param request The servlet request we are processing
   */
  protected String selectEncoding(ServletRequest request) {

    return (this.encoding);

  }

}

<filter>
  <filter-name>Set Character Encoding</filter-name>
  <filter-class>filters.SetCharacterEncodingFilter</filter-class>
  <init-param>
   <param-name>encoding</param-name>
   <param-value>UTF-8</param-value>
  </init-param>
 </filter>
 <filter-mapping>
  <filter-name>Set Character Encoding</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>

#Application Resource for the logon.jsp
logon.jsp.title=登录页
logon.jsp.page.heading=欢迎 世界!
logon.jsp.prompt.username=用户名:
logon.jsp.prompt.password=口令:
logon.jsp.prompt.submit=提交
logon.jsp.prompt.reset=复位

#Application Resource for the main.jsp
main.jsp.title=主页
main.jsp.welcome=欢迎:

#Application Resource for the LogonAction.java
error.missing.username=<li><font color="red">没有输入用户名</font></li>
error.missing.password=<li><font color="red">没有输入口令</font></li>

#Application Resource for the UserInfoBo.java
error.noMatch=<li><font color="red">没有匹配的用户</font></li>

#Application Resource for the UserInfoBo.java
error.logon.invalid=<li><font color="red">用户名/口令是无效的</font></li>
error.removed.user=<li><font color="red">找不到该用户</font></li>
error.unexpected=<li><font color="red">不可预期的错误</font></li>

#Application Resource for the logon.jsp
logon.jsp.title=/u767b/u5f55/u9875
logon.jsp.page.heading=/u6b22/u8fce /u4e16/u754c!
logon.jsp.prompt.username=/u7528/u6237/u540d:
logon.jsp.prompt.password=/u53e3/u4ee4:
logon.jsp.prompt.submit=/u63d0/u4ea4
logon.jsp.prompt.reset=/u590d/u4f4d

#Application Resource for the main.jsp
main.jsp.title=/u4e3b/u9875
main.jsp.welcome=/u6b22/u8fce:

#Application Resource for the LogonAction.java
error.missing.username=<li><font color="red">/u6ca1/u6709/u8f93/u5165/u7528/u6237/u540d</font></li>
error.missing.password=<li><font color="red">/u6ca1/u6709/u8f93/u5165/u53e3/u4ee4</font></li>

#Application Resource for the UserInfoBo.java
error.noMatch=<li><font color="red">/u6ca1/u6709/u5339/u914d/u7684/u7528/u6237</font></li>

#Application Resource for the UserInfoBo.java
error.logon.invalid=<li><font color="red">/u7528/u6237/u540d//u53e3/u4ee4/u662f/u65e0/u6548/u7684</font></li>
error.removed.user=<li><font color="red">/u627e/u4e0d/u5230/u8be5/u7528/u6237</font></li>
error.unexpected=<li><font color="red">/u4e0d/u53ef/u9884/u671f/u7684/u9519/u8bef</font></li>