[Java Web] Struts2 add up (one)

Struts2 Environment Configuration

1. Import STRUTS2 need jar package
2. Create a Struts.xml file under the web-inf/classes (SRC) folder
3. Adding struts filter information to the Web. xml file

frequently use configuration files

1. Struts.xml: Used to store the action mapping relationship, set up struts configuration information
2. Web. XML: Struts filter for configuring containers, general configuration such as the following:

   <filter>      <filter-name>struts2</filter-name>      <filter-class>          Org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter      </filter-class>  </ filter>  <filter-mapping>      <filter-name>struts2</filter-name>      <url-pattern >/*</url-pattern>  </filter-mapping>

3. Struts-default.xml:struts2 default configuration information, generally not recommended changes
4. The default settings information for the default.properties:Struts2. Same not recommended changes

Action
The core functionality of STRUTS2 is typically made up of two parts: the action map of Struts.xml and the action entity class written in Java. In Struts.xml, you typically use a series of tags, such as <action>, <result>, <package>, to complete the action mapping, with their properties:

2. Package

   	must	descriptive narrative / td>
   name	Yes
   extends
   namespace	no
   abstact	no

   
   
3. Action

   Property	Whether you must	Descriptive narrative
   Name	Is	of the request Action name
   Class	Whether	Action handle the corresponding detailed path of the class
   Method	Whether	Specify Action the method name in
   Converter	Whether	Specify Action types of converters used

   
   
5. Result

   Property	Whether you must	Descriptive narrative
   Name	Whether	Action returns the view name. I feel success
   Type	Whether	Return the result type, default feel dispatcher

A simple action map can be written as:

<package name= "admin" extends= "Struts-default" ><action name= "Welcome" class= "Struts.action.WelcomeAction" ><result>/welcome.jsp</result></action></package>

The action entity class needs to inherit the Actionsupport class and rewrite his Execute method (or any other method that returns a string type and corresponds to the method property in the action tag). and returns the string corresponding to the result label Name property. The entity classes corresponding to the above configuration are:

public class Welcomeaction extends Actionsupport {public String execute () {return SUCCESS;}}

Dynamic Method Invocation (DMI)
The ability to configure only one method in an action is inconvenient in practical applications, and STRUTS2 supports specifying different methods of invoking the action class in the URL. The format is "action name! Method name".

Before using this feature, you need to include the following code in Struts.xml to open DMI:

<constant name= "Struts.enable.DynamicMethodInvocation" value= "true"/>

It is then easy to invoke the corresponding method in the action class with the return value of type string.

wildcard character (wildcard)
STRUTS2 supports wildcard operations. This reduces the effort by contract format when a large number of actions need to be configured. It uses "*" instead of the easy-to-transform word, and then takes the {n} out. n represents the nth wildcard character. For example, a program needs to have 4 action. The names are dogaction, Cataction, Birdaction, and Fishaction, respectively.

Assume that the previous method requires the configuration of the 4 action mapping relationship. However, using wildcards only requires one of the following action:

<action name= "buy*" class= "struts.action. {1} Action "><result>/pay.jsp</result></action>

The wildcard has a wide scope, and the action's name can change the result of method, class, and result, and so on. Often use can save a lot of time. However, a good consistency lattice formula is required beforehand.

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[Java Web] Struts2 add up (one)