Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Instantiates a class that conforms to the JavaBeans specification. This tag has a body which can contain a number of Param elements to set any mutator methods on that class.

If the var attribute is set on the BeanTag, it will place the instantiated bean into the stack's Context.

 Bean标签，当然需要一个JavaBean。它的属性值的操作是经由Bean标签中的参数属性来进行赋值。当然，它还有一个id属性可以进行赋值，这样就可以在上下文中使用这个Bean如果在BeanTag中设置了var属性值，那么它将把实例化后的bean放入到stack's Context中。

Parameters

Examples

<-- in freemarker form -->
[@s.bean name="org.apache.struts2.example.counter.SimpleCounter" var="counter"]
  [s:param name="foo" value="BAR"/]
  The value of foo is : [s:property value="foo"/], when inside the bean tag.<br />
[/s:bean]

<-- in jsp form -->
<s:bean name="org.apache.struts2.example.counter.SimpleCounter" var="counter">
  <s:param name="foo" value="BAR" />
  The value of foot is : <s:property value="foo"/>, when inside the bean tag <br />
</s:bean>

This example instantiates a bean called SimpleCounter and sets the foo property (setFoo('BAR')). The SimpleCounter object is then pushed onto the Valuestack, which means that we can call its accessor methods (getFoo()) with the Property tag and get their
values.

这个例子实例化了一个名叫SimpleCounter的bean，并设置foo属性(setFoo(‘BAR’))。然后将SimpleCounter对象压入值栈(Valuestack)中，这意味着我们可以调用property tag的访问方法(getFoo())来得到它的值。

在上面的例子中，id的属性值已经设为counter，这意味着SimpleCounter对象压入值栈(Valuestack)后可以通过如下标签来访问它：

In the above example, the id has been set to a value of counter. This means that the SimpleCounter class will be placed into the stack's context. You can access the SimpleCounter class using a Struts tag:

<-- jsp form -->
<s:property value="#counter" />


<-- freemarker form -->
[s:property value="#counter.foo"/]

In the property tag example, the # tells Ognl to search the context for the SimpleCounter class which has an id(key) of
counter

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<s:date name="person.birthday" format="dd/MM/yyyy" />
<s:date name="person.birthday" format="%{getText('some.i18n.key')}" />
<s:date name="person.birthday" nice="true" />
<s:date name="person.birthday" />

<s:debug>

这个学过struts的地球人都知道：

     输出值栈中的内容

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Gets a resource bundle and place it on the value stack. This allows the text tag to access messages from any bundle, and not just the bundle associated with the current action.

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
name	true	String	false	String	Name of resource bundle to use (eg foo/bar/customBundle)

Examples

<s:i18n name="myCustomBundle">
   The i18n value for key aaa.bbb.ccc in myCustomBundle is <s:property value="text('aaa.bbb.ccc')" />
</s:i18n>

 

include

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Include a servlet's output (result of servlet or a JSP page).

Note: Any additional params supplied to the included page are not accessible within the rendered page through the <s:property...> tag since no valuestack will be created. You can, however, access them in a servlet via the HttpServletRequest
object or from a JSP page via a scriptlet.

包含一个servlet的输入（servlet或JSP页面的结果）。

Note: 你不能通过<s:property...>来访问所包含页面的任何属性，因为没有值(valuestack)会被创建。然而，你可以通过HttpServletRequest对象在一个servlet中来访问它们，或者是通过scriptlet在jsp页面上访问它们。

How To access parameters Parameters are passed as request parameters, so use the ${param.ParamName} notation to access them. Do not use the property tag to access parameters in included files. 参数作为request参数被传递，因此可以使用$ {param.ParamName}标记来访问它们。不要使用<s:property...>标记来访问包含文件的参数。

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
value	true		false	String	The jsp/servlet output to include

Example

<-- One: -->
<s:include value="myJsp.jsp" />

<-- Two: -->
<s:include value="myJsp.jsp">
   <s:param name="param1" value="value2" />
   <s:param name="param2" value="value2" />
</s:include>

<-- Three: -->
<s:include value="myJsp.jsp">
   <s:param name="param1">value1</s:param>
   <s:param name="param2">value2</s:param>
</s:include>

 

Example one - do an include myJsp.jsp page
Example two - do an include to myJsp.jsp page with parameters param1=value1 and param2=value2
Example three - do an include to myJsp.jsp page with parameters param1=value1 and param2=value2

param

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

This tag can be used to parameterize other tags.

The include tag and bean tag are examples of such tags.

The parameters can be added with or without a name as key. If the tag provides a name attribute the parameters are added using the {@link Component#addParameter(String, Object) addParamter} method. For unnamed parameters the Tag must implement the UnnamedParametric
interface defined in this class (e.g. The TextTag does this).

This tag has the following two paramters.

• name (String) - the name of the parameter
• value (Object) - the value of the parameter

Note: When you declare the param tag, the value can be defined in either a
value attribute or as text between the start and end tag. Struts behaves a bit different according to these two situations. This is best illustrated using an example:

<param name="color">blue</param> <-- (A) -->
<param name="color" value="blue"/> <-- (B) -->
In the first situation (A) the value would be evaluated to the stack as a java.lang.String object. And in situation (B) the value would be evaluated to the stack as a
java.lang.Object object.
For more information see WW-808.

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
name	false		false	String	Name of Parameter to set
value	false	The value of evaluating provided name against stack	false	String	Value expression for Parameter to set

Examples

<pre>
<ui:component>
 <ui:param name="key"     value="[0]"/>
 <ui:param name="value"   value="[1]"/>
 <ui:param name="context" value="[2]"/>
</ui:component>
</pre>

 

where the key will be the identifier and the value the result of an OGNL expression run against the current ValueStack.

property

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Used to get the property of a value, which will default to the top of the stack if none is specified.

用于获取一个属性的值。Property顾名思义，可以与<s:bean>标签结合使用，一个是给bean赋值，一个是从bean中读取值。

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
default	false		false	String	The default value to be used if value attribute is null
escape	false	true	false	Boolean	Deprecated. Use 'escapeHtml'. Whether to escape HTML
escapeCsv	false	false	false	Boolean	Whether to escape CSV (useful to escape a value for a column)
escapeHtml	false	true	false	Boolean	Whether to escape HTML
escapeJavaScript	false	false	false	Boolean	Whether to escape Javascript
escapeXml	false	false	false	Boolean	Whether to escape XML
value	false	<top of stack>	false	Object	Value to be displayed

Examples

<s:push value="myBean">
    <!-- Example 1: -->
    <s:property value="myBeanProperty" />

    <!-- Example 2: -->TextUtils
    <s:property value="myBeanProperty" default="a default value" />
</s:push>

 

Example 1 prints the result of myBean's getMyBeanProperty() method.
Example 2 prints the result of myBean's getMyBeanProperty() method and if it is null, print 'a default value' instead.

 

push

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Push value on stack for simplified usage.

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
value	true		false	String	Value to push on stack

Examples

<s:push value="user">
    <s:propery value="firstName" />
    <s:propery value="lastName" />
</s:push>

Pushed user into the stack, and hence property tag could access user's properties
(firstName, lastName etc) since user is not at the top of the stack

<s:push value="myObject">                              ----- (1)
     <s:bean name="jp.SomeBean" var="myBean"/>        ----- (2)
        <s:param name="myParam" value="top"/>        ----- (3)
     </s:bean>
 </s:push>

when in (1), myObject is at the top of the stack
when in (2), jp.SomeBean is in the top of stack, also in stack's context with key myBean
when in (3), top will get the jp.SomeBean instance

<s:push value="myObject">                                       ---(A)
   <s:bean name="jp.SomeBean" var="myBean"/>                   ---(B)
      <s:param name="myParam" value="top.mySomeOtherValue"/>  ---(C)
   </s:bean>
</s:push>

when in (A), myObject is at the top of the stack
when in (B), jp.SomeBean is at the top of the stack, also in context with key myBean
when in (C), top refers to jp.SomeBean instance. so top.mySomeOtherValue would invoke SomeBean's mySomeOtherValue() method

<s:push value="myObject">                                 ---- (i)
   <s:bean name="jp.SomeBean" var="myBean"/>             ---- (ii)
      <s:param name="myParam" value="[1].top"/>         -----(iii)
   </s:bean>
</s:push>

when in (i), myObject is at the top of the stack
when in (ii), jp.SomeBean is at the top of the stack, followed by myObject
when in (iii), [1].top will returned top of the cut of stack starting from myObject, namely myObject itself

set

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

The set tag assigns a value to a variable in a specified scope. It is useful when you wish to assign a variable to a complex expression and then simply reference that variable each time rather than the complex expression. This is useful in both cases: when
the complex expression takes time (performance improvement) or is hard to read (code readability improvement).

Set标签比较简单。Set标签用户将某一值赋给某一变量，因此，任何对该项值的引用都可以通过该变量来得到该值。该变量的活动范围可自定义。如下例中，定义一健/值对，对值的引用，直接引用值就可以

If the tag is used with body content, the evaluation of the value parameter is omitted. Instead, the String to which the body eveluates is set as value for the scoped variable.

The scopes available are as follows :-

• application - the value will be set in application scope according to servlet spec. using the name as its key
• session - the value will be set in session scope according to servlet spec. using the name as key
• request - the value will be set in request scope according to servlet spec. using the name as key
• page - the value will be set in page scope according to servlet sepc. using the name as key
• action - the value will be set in the request scope and Struts' action context using the name as key

NOTE:

If no scope is specified, it will default to action scope.

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
id	false		false	String	Deprecated. Use 'var' instead
name	false		false	String	Deprecated. Use 'var' instead
scope	false	action	false	String	The scope in which to assign the variable. Can be application, session, request, page, or action.
value	false		false	String	The value that is assigned to the variable named name
var	false		false	String	Name used to reference the value pushed into the Value Stack

Examples

s:set name="personName" value="person.name"/>
Hello, <s:property value="#personName"/>. How are you?

text

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Please make sure you have read the Tag Syntax document and understand how tag attribute syntax works.

Description

Render a I18n text message.

The message must be in a resource bundle with the same name as the action that it is associated with. In practice this means that you should create a properties file in the same package as your Java class with the same name as your class,
but with .properties extension.

If the named message is not found in a property file, then the body of the tag will be used as default message. If no body is used, then the stack will be searched, and if a value is returned, it will written to the output. If no value
is found on the stack, the key of the message will be written out.

For more details on using resource bundles with Struts 2 read the

localization guide.

Parameters

Dynamic Attributes Allowed: false
Name	Required	Default	Evaluated	Type	Description
id	false		false	String	Deprecated. Use 'var' instead
name	true		false	String	Name of resource property to fetch
searchValueStack	false	true	false	Boolean	Search the stack if property is not found on resources
var	false		false	String	Name used to reference the value pushed into the Value Stack

Examples

Accessing messages from a given bundle (the i18n Shop example bundle in the first example) and using bundle defined through the framework in the second example.</p>

<!-- First Example -->
<s:i18n name="struts.action.test.i18n.Shop">
    <s:text name="main.title"/>
</s:i18n>

<!-- Second Example -->
<s:text name="main.title" />

<!-- Third Examlpe -->
<s:text name="i18n.label.greetings">
   <s:param >Mr Smith</s:param>
</s:text>

Other example

<s:text name="format.money"><s:param name="value" value="myMoneyValue"/></s:text>

where the following is in a regular (possibly locale-specific) properties file:

format.money={0,number,currency}

For more about formatting text, see

1. http://java.sun.com/j2se/1.4.2/docs/api/java/text/MessageFormat.html
2. http://java.sun.com/docs/books/tutorial/i18n/format/decimalFormat.html

If you wish to use i18n in your tag attributes

This will not work:

<s:textfield name="lastName" label="<s:text name="person.lastName"/>" ../>

Instead, you should use the getText() method that you inherit when your Action extends XWork's ActionSupport:

<s:textfield name="lastName" label="getText('person.lastName')" ../>