filterconfig struts2执行流程(2)

if (excludedPatterns != null && prepare.isUrlExcluded(request, excludedPatterns)) {
    chain.doFilter(request, response);
}

这个excludedPatterns是一个List< Pattern >集合，里面包含了不被struts2过滤器拦截的url。filterconfig看这一句：prepare.isUrlExcluded(request, excludedPatterns)，判断这个请求里面是否包含这样的url，跟进源码查看一具体的实现：

public boolean isUrlExcluded( HttpServletRequest request, List<Pattern> excludedPatterns ) {
    if (excludedPatterns != null) {
        // 1.获取当前请求中的uri
        String uri = RequestUtils.getUri(request);
        // 2.查看集合中是否有与之匹配的，有就返回true
        for ( Pattern pattern : excludedPatterns ) {
            if (pattern.matcher(uri).matches()) {
                return true;
            }
        }
    }
    return false;
}

知道了是通过excludedPatterns来判断哪个url不被拦截，那么这个excludedPatterns的值是从哪里来的呢？初步猜测是在StrutsPreparedAndExecuteFilter初始化（init）的时候设置的…果不其然，看源码：

public void init(FilterConfig filterConfig) throws ServletException {
    InitOperations init = new InitOperations();
    Dispatcher dispatcher = null;
    try {
        FilterHostConfig config = new FilterHostConfig(filterConfig);
        init.initLogging(config);
        dispatcher = init.initDispatcher(config);
        init.initStaticContentLoader(config, dispatcher);

        prepare = new PrepareOperations(filterConfig.getServletContext(), dispatcher);
        execute = new ExecuteOperations(filterConfig.getServletContext(), dispatcher);
        // 就是这里，创建了不匹配的url列表
        this.excludedPatterns = init.buildExcludedPatternsList(dispatcher);

        postInit(dispatcher, filterConfig);
    } finally {
        if (dispatcher != null) {
            dispatcher.cleanUpAfterInit();
        }
        init.cleanup();
    }
}

本文来自电脑杂谈，转载请注明本文网址：
http://www.pc-fly.com/a/jisuanjixue/article-78438-2.html