struts2的初步认识

2024-04-08 14:03:52

Struts2是一个基于MVC设计模式的Web应用框架，它本质上相当于一个servlet，在MVC设计模式中，Struts2作为控制器(Controller)来建立模型与视图的数据交互。

一、 Struts2的环境搭建

1.在maven项目的pom.xml中引入Struts的依赖

1  <dependency>
2 2             <groupId>org.apache.struts</groupId>
3 3             <artifactId>struts2-core</artifactId>
4 4             <version>2.5.13</version>
5 5      </dependency>

2.导入Struts所需的配置文件

struts-base.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
 4     "http://struts.apache.org/dtds/struts-2.5.dtd">
 5 <struts>
 6     <!-- 设置编码格式 -->
 7     <constant name="struts.i18n.encoding" value="UTF-8" />
 8     <!-- 开启动态方法调用 -->
 9     <constant name="struts.devMode" value="true" />
10     <!-- 修改代码在不重启项目的情况下也能立即生效 -->
11     <constant name="struts.configuration.xml.reload" value="true" />
12     <constant name="struts.i18n.reload" value="true" />
13     <!-- 开启动态方法调用 -->
14     <constant name="struts.enable.DynamicMethodInvocation" value="true" />
15 
16     <!-- struts2.5以后加这个配置才能开启动态方法调用 -->
17     <package name="base" extends="struts-default" abstract="true">
18         <global-allowed-methods>regex:.*</global-allowed-methods>
19     </package>
20 </struts>

struts-sy.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
 4     "http://struts.apache.org/dtds/struts-2.5.dtd">
 5 <struts>
 6     <!-- /user/bookAction?methodName=list 
 7         /sy/bookAction?methodName=list
 8     -->
 9     <package name="sy" extends="base" namespace="/sy">
10         <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}">
11             <result name="rs">/rs.jsp</result>
12         </action>
13     </package>
14 </struts>

struts.xml

<?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>
    <!-- struts默认的配置文件 -->
    <include file="struts-default.xml"></include>
    <!-- struts基础配置文件 -->
    <include file="struts-base.xml"></include>
    
    <include file="struts-sy.xml"></include>
</struts>

3.配置核心过滤器 web.xml

 1 <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 2          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
 4          version="3.1">
 5   <display-name>Archetype Created Web Application</display-name>
 6       <filter>
 7           <filter-name>struts</filter-name>
 8           <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
 9       </filter>
10       <filter-mapping>
11           <filter-name>struts</filter-name>
12           <url-pattern>*.action</url-pattern>
13       </filter-mapping>
14 </web-app>

二、动态方法的调用

action代码

public String add() {
        System.out.println("调用add方法");
        return "rs";
        
    }
    
    public String del() {
        System.out.println("调用del方法");
        return "rs";
        
    }

js页面代码测试是否成功

1 <a href="${pageContext.request.contextPath }/sy/demo_add.action">新增</a>
2 
3 <a href="${pageContext.request.contextPath }/sy/demo_del.action">删除</a>

控制台有相应的输出就是成功了

三、struts前台传递参数到后台

三种方法：

　　　　　　　 1.implements modelDrivern
　　　　　　2.类实例.属性名
　　　　　　3.set/get

　　先建立一个Cal实体类

 1 package com.liuwenwu.entity;
 2 
 3 public class Cal {
 4     
 5     private String num1;
 6     private String num2;
 7     public String getNum1() {
 8         return num1;
 9     }
10     public void setNum1(String num1) {
11         this.num1 = num1;
12     }
13     public String getNum2() {
14         return num2;
15     }
16     public void setNum2(String num2) {
17         this.num2 = num2;
18     }
19     @Override
20     public String toString() {
21         return "Cal [num1=" + num1 + ", num2=" + num2 + "]";
22     }
23     
24 
25 }

1.实现modelDrivern

 1 public class HelloAction implements ModelDriven<Cal>,ServletRequestAware{
 2         private Cal cal1=new Cal();    
 3 
 4     @Override
 5     public Cal getModel() {
 6         return cal1;
 7     }
 8 
 9         /**
10      * implements modelDrivern    接收参数值
11      * @return
12      */
13     public String accept1() {
14         System.out.println("cal1:"+cal1);
15 
16         return "rs";    
17     }
18 
19 }

jsp页面代码

1 <a href="${pageContext.request.contextPath }/sy/demo_accept1.action?num1=20&&num2=5">accept1</a>

2.类实例.属性名

 1 private Cal cal2;
 2 
 3     public Cal getCal2() {
 4         return cal2;
 5     }
 6 
 7     public void setCal2(Cal cal2) {
 8         this.cal2 = cal2;
 9     }
10 
11     /**
12      * 类实例.属性名    接收参数值
13      * @return
14      */
15     public String accept2() {
16         System.out.println("cal2:"+cal2);
17         return "rs";
18         
19     }

　jsp页面代码

<a href="${pageContext.request.contextPath }/sy/demo_accept2.action?cal2.num1=20&&cal2.num2=5">accept2</a>

3.set/get

 1 private String sex;
 2 
 3     public String getSex() {
 4         return sex;
 5     }
 6 
 7     public void setSex(String sex) {
 8         this.sex = sex;
 9     }
10 
11     /**
12      * set/get    接收参数值
13      * @return
14      */
15     public String accept3() {
16         System.out.println(sex);
17         return "rs";
18     }

jsp页面代码

1 <a href="${pageContext.request.contextPath }/sy/demo_accept3.action?sex=nv">accept3</a>

四、后台传值到前台　

　set/get定义的属性是可以接受到的
　　req.set.....

　　1.注入方式（耦合）：实现ServletRequestAware接口

 1 public class HelloAction implements ModelDriven<Cal>,ServletRequestAware{
 2     //注入耦合
 3     private HttpServletRequest req;
 4 
 5     /**
 6      * implements modelDrivern    接收参数值
 7      * @return
 8      */
 9     public String accept1() {
10         System.out.println("cal1:"+cal1);
11         //注入耦合
12         req.setAttribute("cal1", cal1);
13         return "rs";    
14     }
15 
16     @Override
17     public void setServletRequest(HttpServletRequest req) {
18         this.req=req;
19         
20     }
21 }

2.非注入（耦合）

 1 /**
 2      * implements modelDrivern    接收参数值
 3      * @return
 4      */
 5     public String accept1() {
 6         System.out.println("cal1:"+cal1);
 7         //非注入耦合
 8         HttpServletRequest request = ServletActionContext.getRequest();
 9         request.setAttribute("cal1", cal1);
10         return "rs";    
11     }

测试：

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