繼承ActionSupport 實現Action與屬性驅動傳參

零碎@流年絮語發表於2020-10-20
繼承

在action中繼承ActionSupport 類，重寫execute方法

所用到的 jar 包

在這裡插入圖片描述

1.配置web.xml檔案

<?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 Blank</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>

2.action介面

package action;

import com.opensymphony.xwork2.ActionSupport;

@SuppressWarnings("serial")
public class SumActionSupport extends ActionSupport {

	private double x;
	private double y;
	private double sum;

	public String execute() {
		String forward = "-";
		sum = x + y;
		if (sum > 0)
			forward = "+";
		return forward;
	}

	public SumActionSupport() {
		super();
		// TODO Auto-generated constructor stub
	}

	public SumActionSupport(double x, double y) {
		super();
		this.x = x;
		this.y = y;
		this.sum = x + y;
	}

	public double getX() {
		return x;
	}

	public void setX(double x) {
		this.x = x;
	}

	public double getY() {
		return y;
	}

	public void setY(double y) {
		this.y = y;
	}

	public double getSum() {
		return sum;
	}

	public void setSum(double sum) {
		this.sum = sum;
	}

}

3.配置struts.xml檔案

<?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.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="true" /> -->

    <package name="default" namespace="/" extends="struts-default">

        <!--  <default-action-ref name="index" />

        <global-results>
            <result name="error">/WEB-INF/jsp/error.jsp</result>
        </global-results>

        <global-exception-mappings>
            <exception-mapping exception="java.lang.Exception" result="error"/>
        </global-exception-mappings> -->

        <action name="opadd" class="action.SumActionSupport" method="execute">
            <result name="+">p.jsp</result>
            <result name="-">n.jsp</result>
        </action>
    </package>

    <include file="example.xml"/>

    <!-- Add packages here -->

</struts>

由於action中的execute為預設方法，method屬性可以省略

4.input.jsp頁面、p.jsp頁面、n.jsp頁面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action="opadd" method="post">
	加數：<input type="text" name="x">
	加數：<input type="text" name="y">
	<input type="submit" value="提交">
	</form>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
 ${x}+ ${y}= ${sum}
</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
 ${x}+ ${y}= ${sum}
</body>
</html>

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