struts2的请求参数的编码和valuestack放在哪了

struts2的请求编码和valuestack放在哪了

首先来看一下Struts2的过滤器的doFilter方法

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {        HttpServletRequest request = (HttpServletRequest) req;        HttpServletResponse response = (HttpServletResponse) res;        try {            prepare.setEncodingAndLocale(request, response);            prepare.createActionContext(request, response);            prepare.assignDispatcherToThread();            if (excludedPatterns != null && prepare.isUrlExcluded(request, excludedPatterns)) {                chain.doFilter(request, response);            } else {                request = prepare.wrapRequest(request);                ActionMapping mapping = prepare.findActionMapping(request, response, true);                if (mapping == null) {                    boolean handled = execute.executeStaticResourceRequest(request, response);                    if (!handled) {                        chain.doFilter(request, response);                    }                } else {                    execute.executeAction(request, response, mapping);                }            }        } finally {            prepare.cleanupRequest(request);        }    }

首先我们来分析一下struts2的请求参数的编码，看一下这个方法。 prepare.setEncodingAndLocale(request, response);从字面意思来看，这个就是设置encoding和locale，当然咯，说话要讲究实际，我们还是去看一下源代码。

public void setEncodingAndLocale(HttpServletRequest request, HttpServletResponse response) {        dispatcher.prepare(request, response);    }

这里调用了dispatcher.prepare()方法，这里我们继续跟下，进入prepare方法

public void prepare(HttpServletRequest request, HttpServletResponse response) {        String encoding = null;        if (defaultEncoding != null) {            encoding = defaultEncoding;        }        if ("XMLHttpRequest".equals(request.getHeader("X-Requested-With"))) {            encoding = "UTF-8";        }        Locale locale = null;        if (defaultLocale != null) {            locale = LocalizedTextUtil.localeFromString(defaultLocale, request.getLocale());        }        if (encoding != null) {            applyEncoding(request, encoding);        }        if (locale != null) {            response.setLocale(locale);        }        if (paramsWorkaroundEnabled) {            request.getParameter("foo"); // simply read any parameter (existing or not) to "prime" the request        }    }

这里我们先看一下这个defaultEncoding。

  /**     * Store state of StrutsConstants.STRUTS_I18N_ENCODING setting.     */    private String defaultEncoding;

好像貌似这里可以通过default.properties中的属性注入进来的。
default.properties里面有这么一条struts.i18n.encoding=UTF-8，说明编码为utf-8，当然我们可以修改这个变量，我们可以在在struts.xml中添加constant节点修改，name=struts.i18n.encoding,value=编码。
说完了这里，去看一下applyEncoding(request, encoding)这个方法。

 private void applyEncoding(HttpServletRequest request, String encoding) {        try {            if (!encoding.equals(request.getCharacterEncoding())) {                // if the encoding is already correctly set and the parameters have been already read                // do not try to set encoding because it is useless and will cause an error                request.setCharacterEncoding(encoding);            }        } catch (Exception e) {            LOG.error("Error setting character encoding to '" + encoding + "' - ignoring.", e);        }    }

这里request.setCharacterEncoding(encoding);发现设置post方式请求的编码。

到此，请求参数的编码到此完毕。

下一步，寻找valuestack放在哪了？
还是来到struts2的过滤器的doFilter方法中，我们去看一下execute.executeAction(request, response, mapping);这一条代码

  public void executeAction(HttpServletRequest request, HttpServletResponse response, ActionMapping mapping) throws ServletException {        dispatcher.serviceAction(request, response, servletContext, mapping);    }

 public void serviceAction(HttpServletRequest request, HttpServletResponse response, ServletContext context, ActionMapping mapping) throws ServletException {        Map<String, Object> extraContext = createContextMap(request, response, mapping, context);        ValueStack stack = (ValueStack) request.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);        boolean nullStack = stack == null;        if (nullStack) {            ActionContext ctx = ActionContext.getContext();            if (ctx != null) {                stack = ctx.getValueStack();            }        }        if (stack != null) {            extraContext.put(ActionContext.VALUE_STACK, valueStackFactory.createValueStack(stack));        }            request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());    }

上述贴出了部分代码，我们需要的是 request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());可以发现是将valuestack放入了request对象中了
到此，源码解析结束