struts1源码学习1

ActionServlet初始化方法init

public class ActionServlet extends HttpServlet//servlet初始化  public void init() throws ServletException {        final String configPrefix = "config/";        final int configPrefixLength = configPrefix.length() - 1;        // Wraps the entire initialization in a try/catch to better handle        // unexpected exceptions and errors to provide better feedback        // to the developer        try {            initInternal();            initOther();            initServlet();            initChain();            getServletContext().setAttribute(Globals.ACTION_SERVLET_KEY, this);            initModuleConfigFactory();            // Initialize modules as needed            ModuleConfig moduleConfig = initModuleConfig("", config);            initModuleMessageResources(moduleConfig);            initModulePlugIns(moduleConfig);            initModuleFormBeans(moduleConfig);            initModuleForwards(moduleConfig);            initModuleExceptionConfigs(moduleConfig);            initModuleActions(moduleConfig);            moduleConfig.freeze();            Enumeration names = getServletConfig().getInitParameterNames();            while (names.hasMoreElements()) {                String name = (String) names.nextElement();                if (!name.startsWith(configPrefix)) {                    continue;                }                String prefix = name.substring(configPrefixLength);                moduleConfig =                    initModuleConfig(prefix,                        getServletConfig().getInitParameter(name));                initModuleMessageResources(moduleConfig);                initModulePlugIns(moduleConfig);                initModuleFormBeans(moduleConfig);                initModuleForwards(moduleConfig);                initModuleExceptionConfigs(moduleConfig);                initModuleActions(moduleConfig);                moduleConfig.freeze();            }            this.initModulePrefixes(this.getServletContext());            this.destroyConfigDigester();        } catch (UnavailableException ex) {            throw ex;        } catch (Throwable t) {            // The follow error message is not retrieved from internal message            // resources as they may not have been able to have been            // initialized            log.error("Unable to initialize Struts ActionServlet due to an "                + "unexpected exception or error thrown, so marking the "                + "servlet as unavailable.  Most likely, this is due to an "                + "incorrect or missing library dependency.", t);            throw new UnavailableException(t.getMessage());        }    }

1、initInternal

 protected void initInternal()        throws ServletException {        try {//internalName是org.apache.struts.action.ActionResources             internal = MessageResources.getMessageResources(internalName);        } catch (MissingResourceException e) {            log.error("Cannot load internal resources from '" + internalName                + "'", e);            throw new UnavailableException(                "Cannot load internal resources from '" + internalName + "'");        }    }

看一下org.apache.struts.action.ActionResources，提示信息数据，我这看到的是英文版和日文版

该方法主要就是加载提示信息数据，加载完成后保存到internal这个属性里

2、initOthers

protected void initOther()        throws ServletException {        String value;//读取actionservlet的配置文件，config默认是/WEB-INF/struts-config.xml        value = getServletConfig().getInitParameter("config");         if (value != null) {            config = value;        }         // Backwards compatibility for form beans of Java wrapper classes        // Set to true for strict Struts 1.0 compatibility//从web.xml读取数据转换器开关        value = getServletConfig().getInitParameter("convertNull");         if ("true".equalsIgnoreCase(value) || "yes".equalsIgnoreCase(value)            || "on".equalsIgnoreCase(value) || "y".equalsIgnoreCase(value)            || "1".equalsIgnoreCase(value)) {            convertNull = true;        }         if (convertNull) {            ConvertUtils.deregister();//几种类型转换            ConvertUtils.register(new BigDecimalConverter(null),                BigDecimal.class);            ConvertUtils.register(new BigIntegerConverter(null),                BigInteger.class);            ConvertUtils.register(new BooleanConverter(null), Boolean.class);            ConvertUtils.register(new ByteConverter(null), Byte.class);            ConvertUtils.register(new CharacterConverter(null), Character.class);            ConvertUtils.register(new DoubleConverter(null), Double.class);            ConvertUtils.register(new FloatConverter(null), Float.class);            ConvertUtils.register(new IntegerConverter(null), Integer.class);            ConvertUtils.register(new LongConverter(null), Long.class);            ConvertUtils.register(new ShortConverter(null), Short.class);        }    }

3、initServlet

初始化actionservlet参数

protected void initServlet()        throws ServletException {        // Remember our servlet name//通过servletconfig获得该servlet名称        this.servletName = getServletConfig().getServletName();         // Prepare a Digester to scan the web application deployment descriptor//apache的一个xml解析工具        Digester digester = new Digester();//把当前对象（ActinServlet）放入digester中        digester.push(this);        digester.setNamespaceAware(true);        digester.setValidating(false);         // Register our local copy of the DTDs that we can find//解析了几个dtd，struts1自带的        for (int i = 0; i < registrations.length; i += 2) {            URL url = this.getClass().getResource(registrations[i + 1]);             if (url != null) {                digester.register(registrations[i], url.toString());            }        }         // Configure the processing rules that we need//类似xpath，得到web-app/servlet-mapping下的参数，并传给ActinServletaddServletMapping方法执行</span>        digester.addCallMethod("web-app/servlet-mapping", "addServletMapping", 2);//将web-app/servlet-mapping/servlet-name的值，作为方法的第一个参数        digester.addCallParam("web-app/servlet-mapping/servlet-name", 0);//将web-app/servlet-mapping/url-pattern的值，作为方法的第二个参数        digester.addCallParam("web-app/servlet-mapping/url-pattern", 1);        // Process the web application deployment descriptor        if (log.isDebugEnabled()) {            log.debug("Scanning web.xml for controller servlet mapping");        }//读取/WEB-INF/web.xml（写死的        InputStream input =            getServletContext().getResourceAsStream("/WEB-INF/web.xml");         if (input == null) {            log.error(internal.getMessage("configWebXml"));            throw new ServletException(internal.getMessage("configWebXml"));        }         try {//解析xml，随后执行了前面的方法addServletMapping            digester.parse(input);        } catch (IOException e) {            log.error(internal.getMessage("configWebXml"), e);            throw new ServletException(e);        } catch (SAXException e) {            log.error(internal.getMessage("configWebXml"), e);            throw new ServletException(e);        } finally {            try {                input.close();            } catch (IOException e) {                log.error(internal.getMessage("configWebXml"), e);                throw new ServletException(e);            }        }         // Record a servlet context attribute (if appropriate)        if (log.isDebugEnabled()) {            log.debug("Mapping for servlet '" + servletName + "' = '"                + servletMapping + "'");        }         if (servletMapping != null) {//把struts1配置的url匹配字符串放入servletcontext中            getServletContext().setAttribute(Globals.SERVLET_KEY, servletMapping);        }    }