struts2配置文件加载流程分析

首先org.apache.struts2.dispatcher. FilterDispatcher.java 中的init（）方法，
    public void init(FilterConfig filterConfig) throws ServletException {
        this.filterConfig = filterConfig;
        String param = filterConfig.getInitParameter("packages");//由此可以看出可以增加参数packages
        String packages = "org.apache.struts2.static template org.apache.struts2.interceptor.debugging";
        if (param != null) {
            packages = param + " " + packages;
        }
        this.pathPrefixes = parse(packages);
        dispatcher = new Dispatcher(filterConfig.getServletContext());
}

org.apache.struts2.dispatcher. Dispatcher.java
首先执行静态代码块：
    static {
        ObjectFactory.setObjectFactory(new StrutsObjectFactory());
        ActionProxyFactory.setFactory(new StrutsActionProxyFactory());
}
执行构造方法
    public Dispatcher(ServletContext servletContext) {
        init(servletContext);
}
然后执行init()方法：

boolean reloadi18n = Boolean.valueOf(
(String) Settings.get(StrutsConstants.STRUTS_I18N_RELOAD)).booleanValue();
上面的语句读取了properties文件。


读取properties文件的流程：
首先执行Org.apache.struts2.dispatcher.Dispatcher.java 类的方法init()中的语句
        boolean reloadi18n = Boolean.valueOf((String)
Settings.get(StrutsConstants.STRUTS_I18N_RELOAD)).booleanValue();

然后执行了org.apacher.struts2.config.Setting.java类中的方法
    public static String get(String name) throws IllegalArgumentException {
        String val = getInstance().getImpl(name);
        return val;
    }
然后执行了
    public static Settings getInstance() {
        return (settingsImpl == null) ? getDefaultInstance() : settingsImpl;
}
然后执行了
    private static Settings getDefaultInstance() {
        if (defaultImpl == null) {
            // Create bootstrap implementation
            defaultImpl = new DefaultSettings(); //产生了一个DefaultSettings对象

            // Create default implementation
            try {
                String className = get(StrutsConstants.STRUTS_CONFIGURATION);

                if (!className.equals(defaultImpl.getClass().getName())) {
                    try {
                        // singleton instances shouldn't be built accessing request or session-specific context data
                        defaultImpl = (Settings) ObjectFactory.getObjectFactory().buildBean(Thread.currentThread().getContextClassLoader().loadClass(className), null);
                    } catch (Exception e) {
                        LOG.error("Could not instantiate settings", e);
                    }
                }
            } catch (IllegalArgumentException ex) {
                // ignore
            }
        }

        return defaultImpl;
}

然后首先执行了语句defaultImpl = new DefaultSettings();
    public DefaultSettings() {
        // Create default implementations
        // Use default properties and struts.properties
        ArrayList list = new ArrayList();

        try {
           list.add(new PropertiesSettings("struts"));//从这里加载struts.properties文件
        } catch (Exception e) {
            log.warn("Could not find or error in struts.properties", e);
        }

        try {
        list.add(new PropertiesSettings("org/apache/struts2/default")); //加载默认的defualt.properties文件
        } catch (Exception e) {
            log.error("Could not find org/apache/struts2/default.properties", e);
        }

        Settings[] configList = new Settings[list.size()];//定义了Settings对象数组
        config = new DelegatingSettings((Settings[]) list.toArray(configList));

        // Add list of additional properties settingss
        try {
            StringTokenizer configFiles = new StringTokenizer((String) config.getImpl(StrutsConstants.STRUTS_CUSTOM_PROPERTIES), ",");
加载了用户自己定义的properties文件。
            while (configFiles.hasMoreTokens()) {
                String name = configFiles.nextToken();

                try {
                    list.add(new PropertiesSettings(name));
                } catch (Exception e) {
                    log.error("Could not find " + name + ".properties. Skipping");
                }
            }

            configList = new Settings[list.size()];
            config = new DelegatingSettings((Settings[]) list.toArray(configList));
        } catch (IllegalArgumentException e) {
            // thrown when Settings is unable to find a certain property
            // eg. struts.custom.properties in default.properties which is commented
            // out
        }

        // Add additional list of i18n global resource bundles
        try {

            LocalizedTextUtil.addDefaultResourceBundle("org/apache/struts2/struts-messages");
            StringTokenizer bundleFiles = new StringTokenizer((String) config.getImpl(StrutsConstants.STRUTS_CUSTOM_I18N_RESOURCES), ", ");

            while (bundleFiles.hasMoreTokens()) {
                String name = bundleFiles.nextToken();
                try {
                    log.info("Loading global messages from " + name);
                    LocalizedTextUtil.addDefaultResourceBundle(name);
                } catch (Exception e) {
                    log.error("Could not find " + name + ".properties. Skipping");
                }
            }
        } catch (IllegalArgumentException e) {
            // struts.custom.i18n.resources wasn't provided
        }
}
看看org.apache.struts2.config.DelegatingSettings.java下面的方法。
/**
     * Gets the specified property - calls getImpl(String) method on config objects in config list
     * until successful.
     *
     * @see #get(String)
     */
    public String getImpl(String name) throws IllegalArgumentException {
        // Delegate to the other settings
        IllegalArgumentException e = null;

        for (int i = 0; i < configList.length; i++) {
            try {
                return configList[i].getImpl(name);
            } catch (IllegalArgumentException ex) {
                e = ex;

                // Try next config
            }
        }

        throw e;
    }

评论

1 楼 allenBen 2007-09-29  

怎么你写的一些代码我没看到啊难道源码还会不同？2.0.9