1、初始化工作
读取配置---转换器-----读取插件
当struts-config.xml配置文件加载到内存，则会创建两个map：ActionConfigs，FromBeans。这两个map都交由ModuleConfig对象管理
a、ActionConfigs的Map装载每个Action配置信息---ActionMapping
b、名为FromBeans的map装载FormBean配置信息---FormBeanConfig
接收请求ActionServlet的doPost方法进行处理，调用process方法，而process方法会创建RequestProcessor对象并调用其process方法
ActionServlet的doPost方法
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
process(request, response);
}
ActionServlet的process方法
protected void process(HttpServletRequest request,HttpServletResponse response)throws IOException, ServletException {
ModuleUtils.getInstance().selectModule(request, getServletContext());
ModuleConfig config = getModuleConfig(request);
RequestProcessor processor = getProcessorForModule(config);
if (processor == null) {
processor = getRequestProcessor(config);
}
processor.process(request, response);
}
RequestProcessor对象的process方法，也是整个ActionServlet的整个核心控制流程
public void process(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
// Identify the path component we will use to select a mapping
String path = processPath(request, response);
if (path == null) {
return;
}
this.processCachedMessages(request, response);
// Identify the mapping for this request
ActionMapping mapping = processMapping(request, response, path);
if (mapping == null) {
return;
}
// Check for any role required to perform this action
if (!processRoles(request, response, mapping)) {
return;
}
// Process any ActionForm bean related to this request
ActionForm form = processActionForm(request, response, mapping);
processPopulate(request, response, form, mapping);
// Validate any fields of the ActionForm bean, if applicable
try {
if (!processValidate(request, response, form, mapping)) {
return;
}
} catch (InvalidCancelException e) {
ActionForward forward = processException(request, response, e, form, mapping);
processForwardConfig(request, response, forward);
return;
} catch (IOException e) {
throw e;
} catch (ServletException e) {
throw e;
}
// Process a forward or include specified by this mapping
if (!processForward(request, response, mapping)) {
return;
}
if (!processInclude(request, response, mapping)) {
return;
}
// Create or acquire the Action instance to process this request
Action action = processActionCreate(request, response, mapping);
if (action == null) {
return;
}
// Call the Action instance itself
ActionForward forward =
processActionPerform(request, response, action, form, mapping);
// Process the returned ActionForward instance
processForwardConfig(request, response, forward);
}
1、struts工作流程：
@@、processPath（）-->截取.do前路径
RequestProcessor对象的process方法的调用processPath方法截取.do前路径
源码如下：
String path = processPath(request, response);
http://127.0.0.1:8080/struts_login/login.do?
username="admin"&password="admin"
path = request.getServletPath();
path=/login.do?username="admin"&password="admin"
int slash = path.lastIndexOf("/");
slash =0;
int period = path.lastIndexOf(".");
period=6;
if ((period >= 0) && (period > slash)) {
path = path.substring(0, period);
path=/login
}
return (path);
--------------------------------------------------------------------
@@、processMapping（）-->根据上一步解析的路径，找到请求路径找到在actionConfigs的map里取得所对应的ActionMapping对象
核心源码如下：
protected ActionMapping processMapping(HttpServletRequest request,
HttpServletResponse response, String path)
throws IOException {
// Is there a mapping for this path?
ActionMapping mapping =
(ActionMapping) moduleConfig.findActionConfig(path);
// If a mapping is found, put it in the request and return it
if (mapping != null) {
request.setAttribute(Globals.MAPPING_KEY, mapping);
return (mapping);
}
<action-mappings>
<action path="/login"
type="com.struts.LoginAction"
name="loginForm"
scope="request"
validate="true"
>
<forward name="success" path="/login_success.jsp"/>
<forward name="error" path="/login_error.jsp"/>
</action>
</action-mappings>
---------------------------------------------------------------------
@@、processActionForm（）--->根据解析action配置的name值找是否scope所对应的域里是否有该请求对应的actionfrom对象，没有则根据actionfrom配置的type的值反射创建actionFrom对象并存入request
protected ActionForm processActionForm(HttpServletRequest request,HttpServletResponse response, ActionMapping mapping) {
ActionForm instance = RequestUtils.createActionForm
(request, mapping, moduleConfig, servlet);
if (instance == null) {
return (null);
}
if ("request".equals(mapping.getScope())) {
request.setAttribute(mapping.getAttribute(), instance);
} else {
HttpSession session = request.getSession();
session.setAttribute(mapping.getAttribute(), instance);
}
return (instance);
}
public static ActionForm createActionForm(HttpServletRequest request,ActionMapping mapping, ModuleConfig moduleConfig,ActionServlet servlet) {
String attribute = mapping.getAttribute();
if (attribute == null) {
return (null);
}
String name = mapping.getName();
//到formBeans的Map中取得FormBeanConfig对象
FormBeanConfig config = moduleConfig.findFormBeanConfig(name);
if (config == null) {return (null);}
ActionForm instance = lookupActionForm(request, attribute, mapping.getScope());
try {if (instance != null ) {return (instance); }
return createActionForm(config, servlet);
}
private static ActionForm lookupActionForm(HttpServletRequest request, String attribute, String scope)
{// Look up any existing form bean instance
ActionForm instance = null;
HttpSession session = null;
if ("request".equals(scope)) {
instance = (ActionForm) request.getAttribute(attribute);
} else {
session = request.getSession();
instance = (ActionForm) session.getAttribute(attribute);
}
return (instance);
}
-------------------------------------------------------------------------------------------------------------------------------
@@、processPopulate（）-->从request里拿出name值所对应的actionform并根据actionform配置自动收集请求参数到对象并存入request里
protected void processPopulate(HttpServletRequest req，HttpServletResponse response,
ActionForm form,
ActionMapping mapping)
throws ServletException {
if (form == null) {
return;
}
form.reset(mapping, request);//收集表单数据前对 表单bean的属性初始化
RequestUtils.populate(form, mapping.getPrefix(), mapping.getSuffix(),
request);
RequestUtils.populate(form, mapping.getPrefix(), mapping.getSuffix(),request);
public static void populate(Object bean,String prefix,String suffix,HttpServletRequest request)
throws ServletException {
HashMap properties = new HashMap();
Enumeration names = null；
names = request.getParameterNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
String stripped = name;
Object parameterValue = null;
parameterValue = request.getParameterValues(na
me);
properties.put(stripped, parameterValue);
}
BeanUtils.populate(bean, properties);
}
public static void populate(Object bean, Map properties)
throws IllegalAccessException, InvocationTargetException {
if ((bean == null) || (properties == null)) {
return;
}
Iterator names = properties.keySet().iterator();
while (names.hasNext()) {
String name = (String)
names.next();
Object value = properties.get(name);
setProperty(bean, name, value);
//收集表单数据后对表单bean的属性值进行验证
if (!processValidate(request, response, form, mapping)) {
return;
}
-------------------------------------------------------------------------
@@、processActionCreate（）--->根据action配置type的值创建action对象.
processActionCreate创建action对象（这里actions是HashMap对象，用map实现创建action对象是单例，而且在创建的过程是加锁防止多个线程在用一个时刻访问同一个action请求）
源码如下：
protected Action processActionCreate(HttpServletRequest request,
HttpServletResponse response, ActionMapping mapping)
throws IOException {
//通过maping对象获取action的类型（全类名用于反射创建对象）
String className = mapping.getType();
Action instance;
//在创建action的过程中加锁确保线程同步
synchronized (actions) {
instance = (Action) actions.get(className);
if (instance != null) {
return (instance);
}
try {
instance = (Action) RequestUtils.applicationInstance(className);
} catch (Exception e) {
return (null);
}
actions.put(className, instance);
}
if (instance.getServlet() == null) {
instance.setServlet(this.servlet);
}
return (instance);
}
---------------------------------------------------------------------------------------------------------------------------------
@@、processActionPerform（）---->调用processActionPerform()把request，response，actionform，actionmapping参数注入action对象的execte方法.创建action对象成功则执行ActionForward forward = processActionPerform(request, response, action, form, mapping);其实质是调用execute方法并注入requst,rresponse,actionform,mapping参数并返回ActionFword的转向信息。
protected ActionForward processActionPerform(HttpServletRequest request,HttpServletResponse response,Action action,ActionForm form,ActionMapping mapping)throws IOException, ServletException {
try {
return (action.execute(mapping, form, request, response));
} catch (Exception e) {
return (processException(request, response,
e, form, mapping));
}
}
---------------------------------------------------------------------
@@、processForwardConfig（）--->执行execte方法后，返回的是ActionForward对象（封装了转向信息和转向方式），根据配置文件的forward标签里的name的值拿和path值注入actionforward对象，返回给actionservlet，actionservlet对actionforward进行分析（不写redirect则默认服务器跳转，否则是客户端跳转）转向结果页面
protected void processForwardConfig(HttpServletRequest request,
HttpServletResponse response,ForwardConfig forward)throws IOException, ServletException {
if (forward == null) { return;}
String forwardPath = forward.getPath();
String uri = null;
uri = forwardPath;
if (forward.getRedirect()) //如果为重定向
{
response.sendRedirect( uri);//客户端跳转
} else {
doForward(uri, request, response); //服务端端跳转
}
}
protected void doForward(
String uri,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
RequestDispatcher rd = getServletContext().getRequestDispatcher(uri);
rd.forward(request, response);
}