一.Struts2配置文件

1.struts.properties

在学习Action之前先学下Struts2的配置文件，与Struts2相关的配置文件有好几个，常用的有Struts.xml,web.xml,这两个在MyStruts2的项目中也有使用，其实还有一个可选的配置文件，主要配置Struts2的一些属性,struts.properties.它主要用来配置一些参数，每个可配置的参数都有默认值，如无需修改修改参数任何值，可不添加。默认属性位于包org/apache/struts2下的default.properyies.用户可以在WEB-INF/classes下创建struts.properties覆盖默认的属性。

## $Id$## Licensed to the Apache Software Foundation (ASF) under one# or more contributor license agreements.  See the NOTICE file# distributed with this work for additional information# regarding copyright ownership.  The ASF licenses this file# to you under the Apache License, Version 2.0 (the# "License"); you may not use this file except in compliance# with the License.  You may obtain a copy of the License at##  http://www.apache.org/licenses/LICENSE-2.0## Unless required by applicable law or agreed to in writing,# software distributed under the License is distributed on an# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY# KIND, either express or implied.  See the License for the# specific language governing permissions and limitations# under the License.#### START SNIPPET: complete_file### Struts default properties###(can be overridden by a struts.properties file in the root of the classpath)###### This can be used to set your default locale and encoding scheme# struts.locale=en_USstruts.i18n.encoding=UTF-8### if specified, the default object factory can be overridden here### Note: short-hand notation is supported in some cases, such as "spring"###       Alternatively, you can provide a com.opensymphony.xwork2.ObjectFactory subclass name here# struts.objectFactory = spring### specifies the autoWiring logic when using the SpringObjectFactory.### valid values are: name, type, auto, and constructor (name is the default)struts.objectFactory.spring.autoWire = name### indicates to the struts-spring integration if Class instances should be cached### this should, until a future Spring release makes it possible, be left as true### unless you know exactly what you are doing!### valid values are: true, false (true is the default)struts.objectFactory.spring.useClassCache = true### ensures the autowire strategy is always respected.### valid values are: true, false (false is the default)struts.objectFactory.spring.autoWire.alwaysRespect = false### By default SpringObjectFactory doesn't support AOP### This flag was added just temporally to check if nothing is broken### See https://issues.apache.org/jira/browse/WW-4110struts.objectFactory.spring.enableAopSupport = false### if specified, the default object type determiner can be overridden here### Note: short-hand notation is supported in some cases, such as "tiger" or "notiger"###       Alternatively, you can provide a com.opensymphony.xwork2.util.ObjectTypeDeterminer implementation name here### Note: By default, com.opensymphony.xwork2.util.DefaultObjectTypeDeterminer is used which handles type detection###       using generics. com.opensymphony.xwork2.util.GenericsObjectTypeDeterminer was deprecated since XWork 2, it's###       functions are integrated in DefaultObjectTypeDeterminer now.###       To disable tiger support use the "notiger" property value here.#struts.objectTypeDeterminer = tiger#struts.objectTypeDeterminer = notiger### Parser to handle HTTP POST requests, encoded using the MIME-type multipart/form-data# struts.multipart.parser=cos# struts.multipart.parser=pell# struts.multipart.parser=jakarta-streamstruts.multipart.parser=jakarta# uses javax.servlet.context.tempdir by defaultstruts.multipart.saveDir=struts.multipart.maxSize=2097152### Load custom property files (does not override struts.properties!)# struts.custom.properties=application,org/apache/struts2/extension/custom### How request URLs are mapped to and from actions#struts.mapper.class=org.apache.struts2.dispatcher.mapper.DefaultActionMapper### Used by the DefaultActionMapper### You may provide a comma separated list, e.g. struts.action.extension=action,jnlp,do### The blank extension allows you to match directory listings as well as pure action names### without interfering with static resources, which can be specified as an empty string### prior to a comma e.g. struts.action.extension=, or struts.action.extension=x,y,z,,struts.action.extension=action,,### Used by FilterDispatcher### If true then Struts serves static content from inside its jar.### If false then the static content must be available at 
      
       /strutsstruts.serve.static=true### Used by FilterDispatcher### This is good for development where one wants changes to the static content be### fetch on each request.### NOTE: This will only have effect if struts.serve.static=true### If true -> Struts will write out header for static contents such that they will###             be cached by web browsers (using Date, Cache-Content, Pragma, Expires)###             headers).### If false -> Struts will write out header for static contents such that they are###            NOT to be cached by web browser (using Cache-Content, Pragma, Expires###            headers)struts.serve.static.browserCache=true### Set this to false if you wish to disable implicit dynamic method invocation### via the URL request. This includes URLs like foo!bar.action, as well as params### like method:bar (but not action:foo).### An alternative to implicit dynamic method invocation is to use wildcard### mappings, such as 
       
        struts.enable.DynamicMethodInvocation = false### Set this to true if you wish to allow slashes in your action names.  If false,### Actions names cannot have slashes, and will be accessible via any directory### prefix.  This is the traditional behavior expected of WebWork applications.### Setting to true is useful when you want to use wildcards and store values### in the URL, to be extracted by wildcard patterns, such as### 
        
          to match "/foo/edit" or### "/foo/save".struts.enable.SlashesInActionNames = false### Disables support for action: prefixstruts.mapper.action.prefix.enabled = false### Blocks access to actions in other namespace than current with action: prefixstruts.mapper.action.prefix.crossNamespaces = false### use alternative syntax that requires %{} in most places### to evaluate expressions for String attributes for tagsstruts.tag.altSyntax=true### when set to true, Struts will act much more friendly for developers. This### includes:### - struts.i18n.reload = true### - struts.configuration.xml.reload = true### - raising various debug or ignorable problems to errors###   For example: normally a request to foo.action?someUnknownField=true should###                be ignored (given that any value can come from the web and it###                should not be trusted). However, during development, it may be###                useful to know when these errors are happening and be told of###                them right away.struts.devMode = false### when set to true, resource bundles will be reloaded on _every_ request.### this is good during development, but should never be used in production### struts.i18n.reload=false### Standard UI theme### Change this to reflect which path should be used for JSP control tag templates by defaultstruts.ui.theme=xhtmlstruts.ui.templateDir=template### Change this to use a different token to indicate template theme expansionstruts.ui.theme.expansion.token=~~~#sets the default template type. Either ftl, vm, or jspstruts.ui.templateSuffix=ftl### Configuration reloading### This will cause the configuration to reload struts.xml when it is changed### struts.configuration.xml.reload=false### Location of velocity.properties file.  defaults to velocity.propertiesstruts.velocity.configfile = velocity.properties### Comma separated list of VelocityContext classnames to chain to the StrutsVelocityContextstruts.velocity.contexts =### Location of the velocity toolboxstruts.velocity.toolboxlocation=### used to build URLs, such as the UrlTagstruts.url.http.port = 80struts.url.https.port = 443### possible values are: none, get or allstruts.url.includeParams = none### Load custom default resource bundles# struts.custom.i18n.resources=testmessages,testmessages2### workaround for some app servers that don't handle HttpServletRequest.getParameterMap()### often used for WebLogic, Orion, and OC4Jstruts.dispatcher.parametersWorkaround = false### configure the Freemarker Manager class to be used### Allows user to plug-in customised Freemarker Manager if necessary### MUST extends off org.apache.struts2.views.freemarker.FreemarkerManager#struts.freemarker.manager.classname=org.apache.struts2.views.freemarker.FreemarkerManager### Enables caching of FreeMarker templates### Has the same effect as copying the templates under WEB_APP/templates### struts.freemarker.templatesCache=false### Enables caching of models on the BeanWrapperstruts.freemarker.beanwrapperCache=false### See the StrutsBeanWrapper javadocs for more informationstruts.freemarker.wrapper.altMap=true### maxStrongSize for MruCacheStorage for freemarker, when set to 0 SoftCacheStorage which performs better in heavy loaded application### check WW-3766 for more detailsstruts.freemarker.mru.max.strong.size=0### configure the XSLTResult class to use stylesheet caching.### Set to true for developers and false for production.struts.xslt.nocache=false### Whether to always select the namespace to be everything before the last slash or notstruts.mapper.alwaysSelectFullNamespace=false### Whether to allow static method access in OGNL expressions or notstruts.ognl.allowStaticMethodAccess=false### Whether to throw a RuntimeException when a property is not found### in an expression, or when the expression evaluation failsstruts.el.throwExceptionOnFailure=false### Logs as Warnings properties that are not found (very verbose)struts.ognl.logMissingProperties=false### Caches parsed OGNL expressions, but can lead to memory leaks### if the application generates a lot of different expressionsstruts.ognl.enableExpressionCache=true### Indicates if Dispatcher should handle unexpected exceptions by calling sendError()### or simply rethrow it as a ServletException to allow future processing by other frameworks like Spring Securitystruts.handle.exception=true### END SNIPPET: complete_file
        
       
      

2.struts.xml

struts.xml里面配置Action、JSP、Exception、Intercepter等。struts.properties的配置也可以配置在里面。下面的struts.xml是struts2.5中demo自带的配置

      
      
          
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
           
               
                    
                         
                          
                          
                          
                      
                 
                
                
                    
         
          /WEB-INF/showcase.jsp
                 
                
                    
         
          /WEB-INF/help.jsp
                 
                
                    
         
          /WEB-INF/viewSource.jsp
                 
                
                    
         
          /WEB-INF/date.jsp
                 
            
           
               
                
                    
         
          /WEB-INF/empmanager/listSkills.jsp
                     
                 
                
                    
         
          /WEB-INF/empmanager/editSkill.jsp
                     
                     
                 
                
                    
         
          /WEB-INF/empmanager/editSkill.jsp
                     
         
          list.action
                 
                
                    
         
          /WEB-INF/empmanager/editSkill.jsp
                     
         
          list.action
                 
            
           
               
                
                    
         
          /WEB-INF/empmanager/listEmployees.jsp
                     
                 
                
                      
         {1}            
         
          /WEB-INF/empmanager/editEmployee.jsp
                     
         
          execute
                 
                
                    
         
          /WEB-INF/empmanager/editEmployee.jsp
                     
         
          list.action
                 
                
                    
         
          /WEB-INF/empmanager/editEmployee.jsp
                     
         
          list.action
                 
            
       
      
      

<constant>配置struts2的属性，与struts.properties一样。<include>配置多个struts.xml文件，每个都是独立的，作用格式与struts.xml一样。也要有<!DOCTYPE>和根元素<struts>。package里面配置action等。也可以使用<bean>配置POJO类。

3.配置package

Struts2的Action、JSP等都配置在package中，<package>类似于对象，具有可继承性，默认继承struts-default,name属性指定名称，用于继承时引用。如果子package继承父package，子package可以引用父package的所有资源,也可以重新定义一些资源。package还可以配置命名空间，如配置了命名空间，访问时需加上namespace/*.action.

 二、Action

一、Action的形式

Struts2中Action的实现方式有几种，比较灵活。

1.继承ActionSupport类

自定义Action一般直接继承ActionSupport，并定义变量，重写execute()，变量的值会被Struts2通过setter自动赋值，execute()直接使用，返回值为<result>配置。ActionSupport中实现了其他方法，继承它可直接使用数据校验等Struts2集成的方法。

2.实现Action接口

其实ActionSupport是实现Action接口，所以自定义Action也可以直接实现Action接口，只是Action接口里只有一个execute()，以及几个常用的结果名称(success、none、error、input、login等)。

3.不继承任何类的Action

Struts2的Action并不一定实现Action接口，任何的POJO都可以做Action，只要这个Action具有public String execute()方法。如果Struts2发现没有实现Action接口，会通过反射来调用execute()方法。

二、Action的可执行方法

execute()是Action的默认方法，它也可执行其他方法，只要方法没有参数，返回值String类型，里面可以有throw声明也可以没有，Struts2会在运行时根据方法特征判断是否是可执行方法(返回值、参数)，并通过反射执行。

三、Action方法的执行

1.通过URL执行

执行非默认方法，可以使用action!method.action的URL形式访问，action为struts.xml中配置的Action名字，method为Action的方法名，中间用!隔开。

2.将执行方法配置到action

也可以把方法用method配置到action中，省去！符号，这时的Action名称可以随便指定，也可以为每个方法定义一种action，然后使用action名称对应的访问方式访问Action。这样就是同一个action需要重复配置多次。

四、Action中使用POJO

上面的都是理论，下面通过例子来验证上面的理论。

1.创建POJO，这里把model和action的操作分离开来，建了两个类一个User一个UserAction。

package com.cyw.test;import java.util.Date;public class User {    private String name;    private int age;    private Date birthDay;        public Date getBirthDay() {        return birthDay;    }    public void setBirthDay(Date birthDay) {        this.birthDay = birthDay;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}

package com.cyw.test;import java.util.*;public class UserAction {        private static List
      
        userList=new ArrayList
       
        ();        public  List
        
          getUserList() {        return userList;    }        private String title;        private User user;        public User getUser() {        return user;    }    public void setUser(User user) {        this.user = user;    }    public String initAdd()    {        return "initAdd";    }    public String Add()    {        userList.add(user);        setTitle("添加成功");        return "list";    }    public String list()    {        return "list";    }    public String clear()    {        userList.clear();        setTitle("清除");        return "list";    }        public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }}
        
       
      

2.在Struts.xml中增加配置

              
                   
        
         /listuser.jsp
                    
        
         /inituser.jsp
                     
        
         initAdd,Add,list,clear
                    
                
           
      

这里有一个坑看网上使用通配符配置的时候总是提示找不到对应的action，这个问题纠结了好久，费了好久时间才找到原因，原来是struts2版本的问题，我用的是2.5的，在使用通配符时，需要使用<allowed-methods>来配置下允许访问的方法，使用<allowed-methods>*</allowed-methods>都不行。

3.创建listuser.jsp、inituser.jsp页面，一个用来提交表单，一个用来显示列表。

inituser.jsp页面提交表单数据

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib uri="/struts-tags" prefix="struts" %>
      
      
       添加用户
      
      
       用户列表
      
      
       清空用户
      
          
           
           
           
       
      

listuser.jsp显示数据

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>    <%@ taglib uri="/struts-tags" prefix="struts" %>
      
      
      
       
        
         
姓名
         
年龄
         
出生日期
        
         
         
          
         
          
         
          
        
       
      

这里也有一个坑，由于刚开始接触struts2，所以一些标签都还接触，<struts:iterator>的使用也费了好大的功夫，网上好多都是用id属性，通过id来访问，可我采用这种方法一直没成功。刚才去外面吃完饭回来运行又好了，我也纳闷这是怎么回事。

这里算是对action了解各大概，至于一些细节部分，比如action与jsp之间的传值等以后会慢慢总结。