Struts(二十二)：国际化

  • 如何配置国际化资源文件?

1、Action范围资源文件：在Action类文件所在的路径建立名为ActionName_language_country.properties的文件；

2、包范围资源文件：在包的根路径下建立文件名为package_language_country.properties的属性文件，一旦建立，处于该包下的所有Action都可以访问该资源文件。

注意：包范围资源文件的baseName就是package，不是Action所在的包名。

3、全局资源文件：

　　3.1、命名方式：basename_language_country.properties

　　3.2、struts.xml 中添加配置：<constant name="struts.custom.i18n.resources" value="baseName" />

4、国际化资源文件加载的顺序：离当前Action较近的资源文件被优先加载。

新建项目struts_05:

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.custom.i18n.resources" value="i18n"></constant>
    <package name="default" namespace="/" extends="struts-default">
        <action name="i18nTest" class="com.dx.struts2.i18ntest.I18nAction">
            <result>/i18n.jsp</result>
        </action>
    </package>
</struts>
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web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>Struts 02</display-name>
    <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>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>
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com.dx.struts2.i18ntest.I18nAction.java

package com.dx.struts2.i18ntest;

import com.opensymphony.xwork2.ActionSupport;

public class I18nAction extends ActionSupport {
    private static final long serialVersionUID = 1L;

    @Override
    public String execute() throws Exception {
        return SUCCESS;
    }
}
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index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    
<a href="i18nTest">test</a>
    
</body>
</html>
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i18n.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <s:debug></s:debug>
    <s:form action="">
        <s:textfield name="username" label="UserName"></s:textfield>
        <s:textfield name="username" label="%{getText('username')}"></s:textfield>
        <s:textfield name="username" key="username"></s:textfield>
        <s:textfield name="password" key="password"></s:textfield>
        <s:submit key="submit"></s:submit>
    </s:form>
</body>
</html>
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src下创建i18n.properties

username=UserName
password=Password
submit=Submit

、i18n_zh_CN.properties

username=u7528u6237u540D
password=u5BC6u7801
submit=u63D0u4EA4

、i18n_en_US.properties

username=UserName
password=Password
submit=Submit

访问index.jsp，点击“test”连接跳转到i18n.jsp页面，并修改浏览器的“语言”，看看界面是否有变化。 

在com.dx.struts2.i18ntest下创建i18n.properties

username=^UserName
password=^Password
submit=^Submit

、i18n_zh_CN.properties

username=^u7528u6237u540D
password=^u5BC6u7801
submit=^u63D0u4EA4

、i18n_en_US.properties

username=^UserName
password=^Password
submit=^Submit

访问index.jsp，点击“test”连接跳转到i18n.jsp页面，并修改浏览器的“语言”，看看界面是否有变化。 

  • 在页面上和Action类中如何访问国际化资源文件的value值

1、在Action类中：若Action实现了TextProvider接口，则可以通过调用getText()方法来获取资源文件文件中的value值；

package com.dx.struts2.i18ntest;

import com.opensymphony.xwork2.ActionSupport;

public class I18nAction extends ActionSupport {
    private static final long serialVersionUID = 1L;

    @Override
    public String execute() throws Exception {
        String username = this.getText("username");
        String password = this.getText("password");
        System.out.println(username);
        System.out.println(password);
        
        return SUCCESS;
    }
}

备注：为什么继承ActionSupport类，因为ActionSupport实现了TextProvider接口。

2、在 jsp 页面上：可以通过s:text标签来访问资源文件中的value值；对于表单（非theme="simple"）标签可以使用表单标签的key属性值：

　　2.1、若有占位符，则可以使用s:text标签中嵌套一个子标签s:param来填充占位符；

　　2.2、可以利用标签和OGNL表达式直接访问值栈中的属性值（对象栈、Map栈）

 修改i18n.jsp的form主题theme=“simple”，发现之前的页面中的标签中的国际化信息都没有被显示，解决方案：

<s:form action="" theme="simple">
        <s:textfield name="username" label="UserName"></s:textfield>
        <s:text name="username" />
        <s:textfield name="username" label="%{getText('username')}"></s:textfield>
        <s:text name="username" />
        <s:textfield name="username" key="username"></s:textfield>
        <s:text name="password" />
        <s:textfield name="password" key="password"></s:textfield>
        <s:submit key="submit" value="%{getText('submit')}"></s:submit>
</s:form>

针对占位符解决方案一：

properties文件中：

time=Time:{0}

jsp:

    <s:text name="time">
        <s:param value="date"></s:param>
    </s:text>

针对占位符解决方案一：

properties文件中：

time2=Time:${date}

jsp:

    <s:text name="time2"></s:text>

I18nAction.java

package com.dx.struts2.i18ntest;

import java.util.Arrays;
import java.util.Date;

import com.opensymphony.xwork2.ActionSupport;

public class I18nAction extends ActionSupport {
    private static final long serialVersionUID = 1L;
    private Date date = null;

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    @Override
    public String execute() throws Exception {
        this.date = new Date();

        String username = this.getText("username");
        String password = this.getText("password");
        String dateTime = this.getText("time", Arrays.asList(this.date));
        System.out.println(username);
        System.out.println(password);
        System.out.println(dateTime);

        return SUCCESS;
    }
}

 

  • 通过超链接动态加载国际化资源文件

实际上通过struts2的超级链接，被i18n拦截器拦截掉，过滤请求中是否包含参数，如果包含参数就设置国际化，并把设置信息保存在session中；

如果请求参数中不包含国际化设置，则查看session中是否已经包含，如果包含，则从session中获取国际化设置；

如果请求参数中不包含国际化设置，且session中也不包含，则从浏览器中获取国际化设置。

流程图：

查看i18n拦截器（com.opensymphony.xwork2.interceptor.I18nInterceptor.java）

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * Licensed 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.
 */

package com.opensymphony.xwork2.interceptor;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.util.LocalizedTextUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

import java.util.Arrays;
import java.util.Locale;
import java.util.Map;

/**
 * <!-- START SNIPPET: description -->
 * <p/>
 * An interceptor that handles setting the locale specified in a session as the locale for the current action request.
 * In addition, this interceptor will look for a specific HTTP request parameter and set the locale to whatever value is
 * provided. This means that this interceptor can be used to allow for your application to dynamically change the locale
 * for the user's session or, alternatively, only for the current request (since XWork 2.1.3).
 * This is very useful for applications that require multi-lingual support and want the user to
 * be able to set his or her language preference at any point. The locale parameter is removed during the execution of
 * this interceptor, ensuring that properties aren't set on an action (such as request_locale) that have no typical
 * corresponding setter in your action.
 * <p/>
 * <p/>For example, using the default parameter name, a request to <b>foo.action?request_locale=en_US</b>, then the
 * locale for US English is saved in the user's session and will be used for all future requests.
 * <p/>
 if there is no locale set (for example with the first visit), the interceptor uses the browser locale.
 * <p/>
 * <!-- END SNIPPET: description -->
 * <p/>
 * <p/> <u>Interceptor parameters:</u>
 * <p/>
 * <!-- START SNIPPET: parameters -->
 * <p/>
 * <ul>
 * <p/>
 * <li>parameterName (optional) - the name of the HTTP request parameter that dictates the locale to switch to and save
 * in the session. By default this is <b>request_locale</b></li>
 * <p/>
 * <li>requestOnlyParameterName (optional) - the name of the HTTP request parameter that dictates the locale to switch to
 * for the current request only, without saving it in the session. By default this is <b>request_only_locale</b></li>
 * <p/>
 * <li>attributeName (optional) - the name of the session key to store the selected locale. By default this is
 * <b>WW_TRANS_I18N_LOCALE</b></li>
 * <p/>
 * </ul>
 * <p/>
 * <!-- END SNIPPET: parameters -->
 * <p/>
 * <p/> <u>Extending the interceptor:</u>
 * <p/>
 * <p/>
 * <p/>
 * <!-- START SNIPPET: extending -->
 * <p/>
 * There are no known extensions points for this interceptor.
 * <p/>
 * <!-- END SNIPPET: extending -->
 * <p/>
 * <p/> <u>Example code:</u>
 * <p/>
 * <pre>
 * <!-- START SNIPPET: example -->
 * &lt;action name="someAction" class="com.examples.SomeAction"&gt;
 *     &lt;interceptor-ref name="i18n"/&gt;
 *     &lt;interceptor-ref name="basicStack"/&gt;
 *     &lt;result name="success"&gt;good_result.ftl&lt;/result&gt;
 * &lt;/action&gt;
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * @author Aleksei Gopachenko
 */
public class I18nInterceptor extends AbstractInterceptor {
    private static final long serialVersionUID = 2496830135246700300L;

    protected static final Logger LOG = LoggerFactory.getLogger(I18nInterceptor.class);

    public static final String DEFAULT_SESSION_ATTRIBUTE = "WW_TRANS_I18N_LOCALE";
    public static final String DEFAULT_PARAMETER = "request_locale";
    public static final String DEFAULT_REQUESTONLY_PARAMETER = "request_only_locale";

    protected String parameterName = DEFAULT_PARAMETER;
    protected String requestOnlyParameterName = DEFAULT_REQUESTONLY_PARAMETER;
    protected String attributeName = DEFAULT_SESSION_ATTRIBUTE;

    // Request-Only = None
    protected enum Storage { SESSION, NONE }

    public I18nInterceptor() {
        if (LOG.isDebugEnabled()) {
            LOG.debug("new I18nInterceptor()");
        }
    }

    public void setParameterName(String parameterName) {
        this.parameterName = parameterName;
    }

    public void setRequestOnlyParameterName(String requestOnlyParameterName) {
        this.requestOnlyParameterName = requestOnlyParameterName;
    }

    public void setAttributeName(String attributeName) {
        this.attributeName = attributeName;
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        if (LOG.isDebugEnabled()) {
            LOG.debug("intercept '#0/#1' {",
                invocation.getProxy().getNamespace(), invocation.getProxy().getActionName());
        }

        LocaleFinder localeFinder = new LocaleFinder(invocation);
        Locale locale = getLocaleFromParam(localeFinder.getRequestedLocale());
        locale = storeLocale(invocation, locale, localeFinder.getStorage());
        saveLocale(invocation, locale);

        if (LOG.isDebugEnabled()) {
            LOG.debug("before Locale=#0", invocation.getStack().findValue("locale"));
        }

        final String result = invocation.invoke();

        if (LOG.isDebugEnabled()) {
            LOG.debug("after Locale=#0", invocation.getStack().findValue("locale"));
            LOG.debug("intercept } ");
        }

        return result;
    }

    /**
     * Store the locale to the chosen storage, like f. e. the session
     *
     * @param invocation the action invocation
     * @param locale the locale to store
     * @param storage the place to store this locale (like Storage.SESSSION.toString())
     */
    protected Locale storeLocale(ActionInvocation invocation, Locale locale, String storage) {
        //save it in session
        Map<String, Object> session = invocation.getInvocationContext().getSession();

        if (session != null) {
            synchronized (session) {
                if (locale == null) {
                    storage = Storage.NONE.toString();
                    locale = readStoredLocale(invocation, session);
                }

                if (Storage.SESSION.toString().equals(storage)) {
                    session.put(attributeName, locale);
                }
            }
        }
        return locale;
    }

    protected class LocaleFinder {
        protected String storage = Storage.SESSION.toString();
        protected Object requestedLocale = null;

        protected ActionInvocation actionInvocation = null;

        protected LocaleFinder(ActionInvocation invocation) {
            actionInvocation = invocation;
            find();
        }

        protected void find() {
            //get requested locale
            Map<String, Object> params = actionInvocation.getInvocationContext().getParameters();

            storage = Storage.SESSION.toString();

            requestedLocale = findLocaleParameter(params, parameterName);
            if (requestedLocale != null) {
                return;
            }

            requestedLocale = findLocaleParameter(params, requestOnlyParameterName);
            if (requestedLocale != null) {
                storage = Storage.NONE.toString();
            }
        }

        public String getStorage() {
            return storage;
        }

        public Object getRequestedLocale() {
            return requestedLocale;
        }
    }

    /**
     * Creates a Locale object from the request param, which might
     * be already a Local or a String
     *
     * @param requestedLocale the parameter from the request
     * @return the Locale
     */
    protected Locale getLocaleFromParam(Object requestedLocale) {
        Locale locale = null;
        if (requestedLocale != null) {
            locale = (requestedLocale instanceof Locale) ?
                    (Locale) requestedLocale :
                    LocalizedTextUtil.localeFromString(requestedLocale.toString(), null);
            if (locale != null && LOG.isDebugEnabled()) {
                LOG.debug("applied request locale=#0", locale);
            }
        }

        if (locale != null && !Arrays.asList(Locale.getAvailableLocales()).contains(locale)) {
            locale = Locale.getDefault();
        }
        return locale;
    }

    /**
     * Reads the locale from the session, and if not found from the
     * current invocation (=browser)
     *
     * @param invocation the current invocation
     * @param session the current session
     * @return the read locale
     */
    protected Locale readStoredLocale(ActionInvocation invocation, Map<String, Object> session) {
        Locale locale = this.readStoredLocalFromSession(invocation, session);

        if (locale != null) {
            return locale;
        }

        return this.readStoredLocalFromCurrentInvocation(invocation);
    }

    protected Locale readStoredLocalFromSession(ActionInvocation invocation, Map<String, Object> session) {
         // check session for saved locale
        Object sessionLocale = session.get(attributeName);
        if (sessionLocale != null && sessionLocale instanceof Locale) {
            Locale locale = (Locale) sessionLocale;
            if (LOG.isDebugEnabled()) {
                LOG.debug("applied session locale=#0", locale);
            }
            return locale;
        }
        return null;
    }

    protected Locale readStoredLocalFromCurrentInvocation(ActionInvocation invocation) {
        // no overriding locale definition found, stay with current invocation (=browser) locale
        Locale locale = invocation.getInvocationContext().getLocale();
        if (locale != null && LOG.isDebugEnabled()) {
            LOG.debug("applied invocation context locale=#0", locale);
        }
        return locale;
    }

    protected Object findLocaleParameter(Map<String, Object> params, String parameterName) {
        Object requestedLocale = params.remove(parameterName);
        if (requestedLocale != null && requestedLocale.getClass().isArray()
                && ((Object[]) requestedLocale).length > 0) {
            requestedLocale = ((Object[]) requestedLocale)[0];

            if (LOG.isDebugEnabled()) {
                LOG.debug("requested_locale=#0", requestedLocale);
            }
        }
        return requestedLocale;
    }

    /**
     * Save the given locale to the ActionInvocation.
     *
     * @param invocation The ActionInvocation.
     * @param locale     The locale to save.
     */
    protected void saveLocale(ActionInvocation invocation, Locale locale) {
        invocation.getInvocationContext().setLocale(locale);
    }

}
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原文地址：https://www.cnblogs.com/yy3b2007com/p/6670315.html