Struts2--入门

一概述
1 Struts2 框架是用在javaEE三层中web层框架
2 Struts2框架是在Structs1和webwork基础之上发展全新的框架
3 Sturuts2解决问题：

基础操作

Sturts2基本原理

4 Sturuts2版本
Sturuts-2.3.24
5 web层常见框架
（1）Sturuts2
（2）springMVC
二 Sturuts2入门案例
1 导入jar包

jar包

maven配置

<!-- https://mvnrepository.com/artifact/asm/asm -->
    <dependency>
      <groupId>asm</groupId>
      <artifactId>asm</artifactId>
      <version>3.3</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/asm/asm-commons -->
    <dependency>
      <groupId>asm</groupId>
      <artifactId>asm-commons</artifactId>
      <version>3.3</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.1</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.4</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.freemarker/freemarker -->
    <dependency>
      <groupId>org.freemarker</groupId>
      <artifactId>freemarker</artifactId>
      <version>2.3.23</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/javassist/javassist -->
    <dependency>
      <groupId>javassist</groupId>
      <artifactId>javassist</artifactId>
      <version>3.11.0.GA</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>2.8.2</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-api -->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.8.2</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/ognl/ognl -->
    <dependency>
      <groupId>ognl</groupId>
      <artifactId>ognl</artifactId>
      <version>3.0.6</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.struts/struts2-core -->
    <dependency>
      <groupId>org.apache.struts</groupId>
      <artifactId>struts2-core</artifactId>
      <version>2.3.24</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.struts.xwork/xwork-core -->
    <dependency>
      <groupId>org.apache.struts.xwork</groupId>
      <artifactId>xwork-core</artifactId>
      <version>2.3.24</version>
    </dependency>

2 创建action

package Action;

/**
 * Created by pc on 2017/9/18.
 */
public class HelloAction {
    /*
    * (1)每次访问servlet时候，都会service方法
    * - 写继承HttpServlet，重写类里面的方法
    * - 在web.xml里面配置servlet访问路径
    * (2)访问action，每次访问action时候，默认执行名称execute
    * - 配置action访问路径
    * */
    public String execute(){
        return "ok";
    }
}

3 配置action访问路径

创建Struts2核心配置文件
- 核心配置文件名称和位置是固定的
- 位置必须在src下面，名称 struts.xml
引入DTD约束

<?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>
</struts>

配置

<?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>
    <package name="hellodemo" extends="struts-default" namespace="/">
        <!--name:访问名称-->
        <action name="hello" class="Action.HelloAction">
            <!--配置方法的返回值到页面-->
            <result name="ok">/hello.jsp</result>
        </action>

    </package>
</struts>

访问路径

http://localhost:8080/Struts2/hello.action

4 配置Struts2过滤器

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</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>
</web-app>

注释：Class FilterDispatcher Deprecated. Since Struts 2.1.3, use StrutsPrepareAndExecuteFilter instead or StrutsPrepareFilterand StrutsExecuteFilter if needing using the ActionContextCleanUp filter in addition to this one..即，从Struts 2.1.3起已被标注为过时的，改用StrutsPrepareAndExecuteFilter

<filter>
<filter-name>struts2</filter-name>
<filter-class>
org.apache.struts2.dispatcher.FilterDispatcher
</filter-class>

会出现

************************************************************************
*                                     WARNING!!!                                         *
*                                                                                                  *   
*>>> FilterDispatcher <<< is deprecated! Please use the new filters! *
*          This can be a source of unpredictable problems!                  *         
*             Please refer to the docs for more details!                         *
*           http://struts.apache.org/2.x/docs/webxml.html              *      
*                                                                                         *
*************************************************************************

运行结果

注释:在idea编辑器中，路径中不需要项目名称
三运行过程图解

图解

Struts2--入门

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