Struts Action 控制器

控制器

即,mvc模型的控制器模型,用於接收數據,傳遞給視圖層,和模型層 默認使用execute方法

查看相關接口

查看com.opensymphony.xwork2下的Action接口 文件以下

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/* * 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. */package com.opensymphony.xwork2;
/** * All actions <b>may</b> implement this interface, which exposes the <code>execute()</code> method. * <p> * However, as of XWork 1.1, this is <b>not</b> required and is only here to assist users. You are free to create POJOs * that honor the same contract defined by this interface without actually implementing the interface. * </p> */public interface Action {
 /** * The action execution was successful. Show result * view to the end user. */ public static final String SUCCESS = "success";
 /** * The action execution was successful but do not * show a view. This is useful for actions that are * handling the view in another fashion like redirect. */ public static final String NONE = "none";
 /** * The action execution was a failure. * Show an error view, possibly asking the * user to retry entering data. */ public static final String ERROR = "error";
 /** * <p> * The action execution require more input * in order to succeed. * This result is typically used if a form * handling action has been executed so as * to provide defaults for a form. The * form associated with the handler should be * shown to the end user. * </p> * * <p> * This result is also used if the given input * params are invalid, meaning the user * should try providing input again. * </p> */ public static final String INPUT = "input";
 /** * The action could not execute, since the * user most was not logged in. The login view * should be shown. */ public static final String LOGIN = "login";

 /** * Where the logic of the action is executed. * * @return a string representing the logical result of the execution. * See constants in this interface for a list of standard result values. * @throws Exception thrown if a system level exception occurs. * <b>Note:</b> Application level exceptions should be handled by returning * an error value, such as <code>Action.ERROR</code>. */ public String execute() throws Exception;
}

大概翻譯一下

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 * *得到Apache軟件基金會（ASF）的許可 *或更多貢獻者許可協議。請參閱NOTICE文件 *與此工做一塊兒分發以獲取更多信息 *關於版權全部權。 ASF許可此文件 *根據Apache許可證2.0版（ * 「執照」）;除非符合規定，不然您不得使用此文件 *使用許可證。您能夠在如下位置獲取許可證副本 * * http://www.apache.org/licenses/LICENSE-2.0 * *除非適用法律要求或書面贊成， *根據許可證分發的軟件分發在 *「按原樣」基礎，不提供任何保證或條件 * KIND，不管是明示的仍是暗示的。請參閱許可證 *管理權限和限制的特定語言 *根據許可證。 * /package com.opensymphony.xwork2;
/ ** *全部動做<b>可能</ b>實現此接口，該接口公開<code> execute（）</ code>方法。 * <p> *可是，從XWork 1.1開始，這<b>不</ b>是必需的，僅用於幫助用戶。您能夠自由建立POJO *遵照此接口定義的相同合同而不實際實現接口。 * </ p> * /public interface Action {
 / ** *行動執行成功。顯示結果 *查看最終用戶。 * / public static final String SUCCESS =「success」;
 / ** *行動執行成功但沒有 *顯示一個視圖。這對於有效的操做頗有用 *以重定向等其餘方式處理視圖。 * / public static final String NONE =「none」;
 / ** *行動執行失敗。 *顯示錯誤視圖，可能會詢問 *用戶重試輸入數據。 * / public static final String ERROR =「error」;
 / ** * <p> *動做執行須要更多輸入 *爲了成功。 *此結果一般用於表格 *處理行動已經執行 *提供表單的默認值。該 *與處理程序關聯的表單應該是 *向最終用戶顯示。 * </ p> * * <p> *若是給定輸入，也會使用此結果 *參數無效，意味着用戶 *應該嘗試再次提供輸入。 * </ p> * / public static final String INPUT =「input」;
 / ** *行動沒法執行，由於 *用戶最多未登陸。登陸視圖 *應該顯示。 * / public static final String LOGIN =「login」;

 / ** *執行動做的邏輯。 * * @return表示執行邏輯結果的字符串。 *有關標準結果值的列表，請參閱此界面中的常量。 * @throws若是發生系統級異常，則拋出異常。 * <b>注意：</ b>應經過返回來處理應用程序級異常 *錯誤值，例如<code> Action.ERROR </ code>。 * / public String execute（）拋出異常;
}

能夠看到,定義了幾個常量一個接口,其中默認執行execute方法,其中幾個常量爲執行結果的常量

擴展實現Action接口的ActionSupport類

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/** * Provides a default implementation for the most common actions. * See the documentation for all the interfaces this class implements for more detailed information. */public class ActionSupport implements Action, Validateable, ValidationAware, TextProvider, LocaleProvider, Serializable

大概翻譯一下

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*爲最多見的操做提供默認實現。 *有關更多詳細信息，請參閱此類實現的全部接口的文檔。 */

因此直接擴展該類便可

從新擴展HelloWorldAction

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package com.ming;
import com.opensymphony.xwork2.ActionSupport;
public class HelloWorldAction extends ActionSupport { private String name;
 @Override public String execute() throws Exception { return "success"; }
 public String getName() { return name; }
 public void setName(String name) { this.name = name; }}

能夠在execute中書寫業務邏輯 從新更改以下

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package com.ming;
import com.opensymphony.xwork2.ActionSupport;
public class HelloWorldAction extends ActionSupport { private String name;
 @Override public String execute() throws Exception { if(SUCCESS.equals(name)){ // 此時返回SUCCESS return SUCCESS; }else{ // 其他內容返回error return ERROR; } }
 public String getName() { return name; }
 public void setName(String name) { this.name = name; }}

在上方,根據name的值,完成了一個業務邏輯,返回是 or 否

編寫配置文件

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts> <!-- 定義調試 --> <constant name="struts.devMode" value="true" /> <!-- 定義數據包 --> <package name="helloworld" extends="struts-default"> <!-- 定義處理邏輯 name爲指定處理的名稱 class 處理的包文件 method 處理將會調用的方法--> <action name="hello" class="com.ming.HelloWorldAction" method="execute"> <!-- 成功返回頁面 --> <result name="success">/HelloWorld.jsp</result> <result name="error">/error.html</result> </action> </package></struts>

效果以下