本站文章除注明转载/出处外,均为本站原创或翻译,转载前请务必署名原文链接~~~

Struts2(2)之配置相关

微信搜索 zze_coding 或扫描 👉 二维码关注我的微信公众号获取更多资源推送:


配置文件的加载顺序

我们已经知道 Struts2 的入口就是核心过滤器 org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter,在程序启动时会执行过滤器的 init 方法,即会执行核心过滤器的 init 方法。

// org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter#init
public void init(FilterConfig filterConfig) throws ServletException {
    InitOperations init = new InitOperations();
    Dispatcher dispatcher = null;
    try {
        FilterHostConfig config = new FilterHostConfig(filterConfig);
        init.initLogging(config);
        //<1>
        dispatcher = init.initDispatcher(config);
        init.initStaticContentLoader(config, dispatcher);

        prepare = new PrepareOperations(dispatcher);
        execute = new ExecuteOperations(dispatcher);
        this.excludedPatterns = init.buildExcludedPatternsList(dispatcher);

        postInit(dispatcher, filterConfig);
    } finally {
        if (dispatcher != null) {
            dispatcher.cleanUpAfterInit();
        }
        init.cleanup();
    }
}

而 Struts2 相关的配置文件就是在 <1> 处的 init.initDispatcher(config) 中加载的。

public Dispatcher initDispatcher( HostConfig filterConfig ) {
    Dispatcher dispatcher = createDispatcher(filterConfig);
    dispatcher.init();
    return dispatcher;
}

再看到 dispatcher.init()

// org.apache.struts2.dispatcher.Dispatcher#init
public void init() {

    if (configurationManager == null) {
        configurationManager = createConfigurationManager(DefaultBeanSelectionProvider.DEFAULT_BEAN_NAME);
    }

    try {
        init_FileManager();
        init_DefaultProperties(); // [1] 加载 struts2-core-2.3.37.jar!/org/apache/struts2/default.properties
        init_TraditionalXmlConfigurations(); // [2] struts2-core-2.3.37.jar!/struts-default.xml、src:struts-plugin.xml、src:struts.xml
        init_LegacyStrutsProperties(); // [3] src:struts.properties
        init_CustomConfigurationProviders(); // [5] 加载配置提供类
        init_FilterInitParameters() ; // [6] 加载 web.xml中 过滤器初始化参数
        init_AliasStandardObjects() ; // [7] 加载 Bean 对象

        Container container = init_PreloadConfiguration();
        container.inject(this);
        init_CheckWebLogicWorkaround(container);

        if (!dispatcherListeners.isEmpty()) {
            for (DispatcherListener l : dispatcherListeners) {
                l.dispatcherInitialized(this);
            }
        }
        errorHandler.init(servletContext);

    } catch (Exception ex) {
        if (LOG.isErrorEnabled())
            LOG.error("Dispatcher initialization failed", ex);
        throw new StrutsException(ex);
    }
}

总结上述,配置文件的加载顺序为:

  • default.properties

  • struts-default.xml

  • struts-plugin.xml

  • struts.xml

  • struts.properties

  • web.xml

加粗的是我们可配置的。

注意:后配置的常量会覆盖之前配置的常量。

Struts.xml 文件

标签含义

package 标签

package 标签称为包,这个包与 Java 中的包概念不一致,它是为了更好地管理 action 的配置。

属性:

  • name:包的名称,只要在一个项目中不重名即可。
  • extends:继承一个包,通常值为 "struts-default"
  • abstract:标识当前包是用来被继承的。
  • namespace:名称空间,与 action 标签的 name 属性共同组成访问路径。

名称空间匹配的优先级从高到低有如下三种:

  1. 带名称的名称空间:namespace="/aaa"
  2. 根名称空间:namespace="/"
  3. 默认名称空间:namespace=""

action 标签

它的主要作用就是指定一个 action 类。
属性:

  • name:与 package 标签上的 namespace 属性共同组成访问路径。
  • class:Action 类的全路径。
  • method:方法名,标识执行 Action 中哪个方法,默认值为 "execute"
  • converter:用于配置类型转换器。  
  • name:与 package 标签上的 namespace 属性共同组成访问路径。
  • class:Action 类的全路径。
  • method:方法名,标识执行 Action 中哪个方法,默认值为 "execute"
  • converter:用于配置类型转换器。  

constant 标签

该标签用来配置一些 Struts2 提前给我们预留的一些常量。
属性:

  • name:常量名。
  • value:常量值。

include 标签

分模块开发时使用,用来引入其它配置文件。

属性:

  • file:要引入的配置文件路径,如:"com/zze/config/demo1/struts.xml"

常量配置

默认常量

在 Struts2 中提供了非常多默认的常量,在 struts2-core-2.3.37.jar!/org/apache/struts2/default.properties 中,如下:

# struts2-core-2.3.37.jar!/org/apache/struts2/default.properties
#
# $Id$
#
# 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_US
struts.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-4110
struts.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-stream
struts.multipart.parser=jakarta
# uses javax.servlet.context.tempdir by default
struts.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 <context_path>/struts
struts.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 <action name="*/*" method="{2}" class="actions.{1}">
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
### <action name="*/*" method="{2}" class="actions.{1}"> to match "/foo/edit" or
### "/foo/save".
struts.enable.SlashesInActionNames = false

### Disables support for action: prefix
struts.mapper.action.prefix.enabled = false

### Blocks access to actions in other namespace than current with action: prefix
struts.mapper.action.prefix.crossNamespaces = false

### use alternative syntax that requires %{} in most places
### to evaluate expressions for String attributes for tags
struts.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 default
struts.ui.theme=xhtml
struts.ui.templateDir=template
### Change this to use a different token to indicate template theme expansion
struts.ui.theme.expansion.token=~~~
#sets the default template type. Either ftl, vm, or jsp
struts.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.properties
struts.velocity.configfile = velocity.properties

### Comma separated list of VelocityContext classnames to chain to the StrutsVelocityContext
struts.velocity.contexts =

### Location of the velocity toolbox
struts.velocity.toolboxlocation=

### used to build URLs, such as the UrlTag
struts.url.http.port = 80
struts.url.https.port = 443
### possible values are: none, get or all
struts.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 OC4J
struts.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 BeanWrapper
struts.freemarker.beanwrapperCache=false

### See the StrutsBeanWrapper javadocs for more information
struts.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 details
struts.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 not
struts.mapper.alwaysSelectFullNamespace=false

### Whether to allow static method access in OGNL expressions or not
struts.ognl.allowStaticMethodAccess=false

### Whether to throw a RuntimeException when a property is not found
### in an expression, or when the expression evaluation fails
struts.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 expressions
struts.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 Security
struts.handle.exception=true
### END SNIPPET: complete_file

下面描述部分配置的含义:

struts.i18n.encoding=UTF-8 # 处理了 POST 请求中文乱码
struts.multipart.saveDir= # 上传文件默认保存位置
struts.multipart.maxSize=2097152 # 上传文件最大大小
struts.action.extension=action,, # 请求路径默认后缀为 action 或空白

配置常量

可以在三个位置来配置常量的值:

struts.xml

直接通过 constant 标签修改常量。例:

// struts.xml
<constant name="struts.action.extension" value="do"/>

struts.properties

需在类根路径下新建一个 struts.properties 文件,在其中以 key=value 的形式修改常量,例:

// struts.properties
struts.action.extension=do

web.xml

需在过滤器中通过配置过滤器的初始化参数修改常量,例:

<!-- web.xml -->
<filter>
    <filter-name>struts2</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    <init-param>
        <param-name>struts.action.extension</param-name>
        <param-value>do</param-value>
    </init-param>
</filter>
# Struts2  

如果这篇文章对您有帮助,可点击下方链接分享给你的朋友们😋,如果遇到问题欢迎评论、留言~~~😇

评论

公众号:zze_coding

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now

×