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>