struts2的初步认识

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

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

2.导入Struts所需的配置文件

struts-base.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>
    <!-- 设置编码格式 -->
    <constant name="struts.i18n.encoding" value="UTF-8" />
    <!-- 开启动态方法调用 -->
    <constant name="struts.devMode" value="true" />
    <!-- 修改代码在不重启项目的情况下也能立即生效 -->
    <constant name="struts.configuration.xml.reload" value="true" />
    <constant name="struts.i18n.reload" value="true" />
    <!-- 开启动态方法调用 -->
    <constant name="struts.enable.DynamicMethodInvocation" value="true" />

    <!-- struts2.5以后加这个配置才能开启动态方法调用 -->
    <package name="base" extends="struts-default" abstract="true">
        <global-allowed-methods>regex:.*</global-allowed-methods>
    </package>
</struts>

struts-sy.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>
    <!-- /user/bookAction?methodName=list 
        /sy/bookAction?methodName=list
    -->
    <package name="sy" extends="base" namespace="/sy">
        <action name="/demo_*" class="com.liuwenwu.web.HelloAction" method="{1}">
            <result name="rs">/rs.jsp</result>
        </action>
    </package>
</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

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>
      <filter>
          <filter-name>struts</filter-name>
          <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class>
      </filter>
      <filter-mapping>
          <filter-name>struts</filter-name>
          <url-pattern>*.action</url-pattern>
      </filter-mapping>
</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

<a href="${pageContext.request.contextPath }/sy/demo_add.action">新增</a>

<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

package com.liuwenwu.entity;

public class Cal {
    
    private String num1;
    private String num2;
    public String getNum1() {
        return num1;
    }
    public void setNum1(String num1) {
        this.num1 = num1;
    }
    public String getNum2() {
        return num2;
    }
    public void setNum2(String num2) {
        this.num2 = num2;
    }
    @Override
    public String toString() {
        return "Cal [num1=" + num1 + ", num2=" + num2 + "]";
    }
    

}

1.实现modelDrivern

public class HelloAction implements ModelDriven<Cal>,ServletRequestAware{
        private Cal cal1=new Cal();    

    @Override
    public Cal getModel() {
        return cal1;
    }

        /**
     * implements modelDrivern    接收参数值
     * @return
     */
    public String accept1() {
        System.out.println("cal1:"+cal1);

        return "rs";    
    }

}

jsp页面代码

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

2.类实例.属性名

    private Cal cal2;

    public Cal getCal2() {
        return cal2;
    }

    public void setCal2(Cal cal2) {
        this.cal2 = cal2;
    }

    /**
     * 类实例.属性名    接收参数值
     * @return
     */
    public String accept2() {
        System.out.println("cal2:"+cal2);
        return "rs";
        
    }

　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

 private String sex;

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    /**
     * set/get    接收参数值
     * @return
     */
    public String accept3() {
        System.out.println(sex);
        return "rs";
    }

jsp页面代码

<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

public class HelloAction implements ModelDriven<Cal>,ServletRequestAware{
    //注入耦合
    private HttpServletRequest req;

    /**
     * implements modelDrivern    接收参数值
     * @return
     */
    public String accept1() {
        System.out.println("cal1:"+cal1);
        //注入耦合
        req.setAttribute("cal1", cal1);
        return "rs";    
    }

    @Override
    public void setServletRequest(HttpServletRequest req) {
        this.req=req;
        
    }
}

2.非注入（耦合）

  /**
     * implements modelDrivern    接收参数值
     * @return
     */
    public String accept1() {
        System.out.println("cal1:"+cal1);
        //非注入耦合
        HttpServletRequest request = ServletActionContext.getRequest();
        request.setAttribute("cal1", cal1);
        return "rs";    
    }