实践——如何在STRUTS中实现多语言支持

首先，要准备多语言的properties文件，作为application resources。

我的实践是在src目录下创建一个resources目录，JAVA会把它看成是一个package。在这个目录下创建各个properties文件，然后再复制并加上_zh_CN或者_en_US作为各locale所需的resources。注意，需要用PropertiesEditor，一个配合eclipse的插件，来编辑中文文件，还要特别注意在preview后再存，同时覆盖原_zh_CN文件。

在JSP的中加入locale=true，就成了。意思是根据用户的流览器的首选locale来决定页面和session中的locale。在IE的语言选项中可以选择所需的locale以调试。

在struts的struts-conf.xml中定义controller的contentType为text/html; charset="UTF-8"。在每个JSP文件的头加上contentType定义，在每个
html的文件的head中加contenType定义。

%@ page contentType="text/html;charset=UTF-8" %
%@ taglib uri="/WEB-INF/taglib/struts-html.tld" prefix="html" %
%@ taglib uri="/WEB-INF/taglib/struts-bean.tld" prefix="bean" %
%@ taglib uri="/WEB-INF/taglib/struts-tiles.tld" prefix="tiles" %

html:html locale="true"
head
meta http-equiv="Content-Type" content="text/html;charset=UTF-8"
title bean:message bundle="TITLES" key="title.window.default" / /title
html:base/
link rel="stylesheet" type="text/css" href="html:rewrite forward='DefaultStyleSheet'/"
/head

表格中的多语言支持可以用一个Filter来完成，

/*
 * Created on 9-Aug-2004
 */
package com.cm.soccer.impl;

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;

/**
 * @author thomas
 *
 * 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:
 *
 * encoding - The character encoding to be configured
 * for this request, either conditionally or unconditionally based on
 * the ignore initialization parameter. This parameter
 * is required, so there is no default.
 * ignore - If set to "true", any character encoding
 * specified by the client is ignored, and the value returned by the
 * selectEncoding() method is set. If set to "false,
 * selectEncoding() is called only if the
 * client has not already specified an encoding. By default, this
 * parameter is set to "true".
 * Although this filter can be used unchanged, it is also easy to
 * subclass it and make the selectEncoding() method more
 * intelligent about what encoding to choose, based on characteristics of
 * the incoming request (such as the values of the Accept-Language
 * and User-Agent headers, or a value stashed in the current
 * user's session.
 */

public class EncodeFilter 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
  /**
   * 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;
  }

  /**
   * 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 {

    String encoding = selectEncoding(request);
    // One way to ensure response set to be UTF-8 is to wrap the response here.
    // But we don't go this way in this implementation.
    // We have put contentType setting in every JSPs.
    // response =
    // new ResponseWrapper((HttpServletResponse) response, encoding);
    // Conditionally select and set the character encoding to be used
    if (ignore  (request.getCharacterEncoding() == null)) {
      if (encoding != null)
        request.setCharacterEncoding(encoding);
    }
    // Pass control on to the next filter
    chain.doFilter(request, response);
  }

  /**
   * Take this filter out of service.
   */
  public void destroy() {
    this.encoding = null;
    this.filterConfig = null;
  }

  // ----------------- 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
   * null.
   * The default implementation unconditionally returns the value configured
   * by the encoding initialization parameter for this
   * filter.
   *
   * @param request The servlet request we are processing
   */
  protected String selectEncoding(ServletRequest request) {
    return (this.encoding);
  }
}

在web.xml中定义，

EncodeFilter
com.cm.soccer.impl.EncodeFilter

encoding
UTF-8

ignore
false

EncodeFilter
cmss