Struts2学习第3天--OGNL、EL、值栈

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

JAVA中的OGNL：

1 调用对象的方法：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

2 访问对象的静态方法：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

3 获取OGNLContext、Root中的数据。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

User:

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

4 访问Context:

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

关键还是在Struts2环境中的使用：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

并没有打印静态方法的值，因为Struts2默认关闭了。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

再次刷新后发现有值了。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

编写demo

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

debug启动打断点发现： root和context均在这里面。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

修改demo返回值

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

运行： Struts2学习第3天--OGNL、EL、值栈-LMLPHP

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

方式1：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

方式2：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

如果有多个user 默认展示栈顶的！！！

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

没有set get方法无法查看但是已经在栈顶了。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

获取值栈的数据：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

在debug里可以找到：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

request中找不到就自动去值栈中寻找。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

修改crm

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

jsp中去掉jstl 引入struts标签库然后不用foreach循环改用s标签。

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

今日代码：

Struts2学习第3天--OGNL、EL、值栈-LMLPHP

package com.itheima.struts2.valuestack;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.util.ValueStack;

/**

 * ValueStack内部结构

 * @author ZWT

 *

 */

public class ValueStackDemo1 extends ActionSupport{

	@SuppressWarnings("unused")

	@Override

	public String execute() throws Exception {

		//获得值栈

		ValueStack valueStack = ActionContext.getContext().getValueStack();

		return SUCCESS;

	}

}

package com.itheima.struts2.valuestack;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.util.ValueStack;

/**

 * 获得ValueStack对象

 * @author ZWT

 *

 */

public class ValueStackDemo2 extends ActionSupport{

	@SuppressWarnings("unused")

	@Override

	public String execute() throws Exception {

		//获得值栈

		ValueStack valueStack1 = ActionContext.getContext().getValueStack();

		//2

		ValueStack valueStack2 = (ValueStack) ServletActionContext.getRequest().getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);

		//一个action实例只会创建一个valuestack

		System.out.println(valueStack1 == valueStack2 );

		return NONE;

	}

}

package com.itheima.struts2.valuestack;

import org.apache.struts2.ServletActionContext;

import com.itheima.struts2.domain.User;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.util.ValueStack;

/**

 * 操作ValueStack

 * @author ZWT

 *

 */

public class ValueStackDemo3 extends ActionSupport{

	private User user;

	public User getUser() {

		return user;

	}

	@SuppressWarnings("unused")

	@Override

	public String execute() throws Exception {

		user = new User("张飞","222");

		return SUCCESS;

	}

}

package com.itheima.struts2.valuestack;

import org.apache.struts2.ServletActionContext;

import com.itheima.struts2.domain.User;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.util.ValueStack;

/**

 * 操作ValueStack :方式2 调用值栈中的方法实现

 * @author ZWT

 *

 */

public class ValueStackDemo4 extends ActionSupport{

	@SuppressWarnings("unused")

	@Override

	public String execute() throws Exception {

		ValueStack valueStack1 = ActionContext.getContext().getValueStack();

		//使用push（Object）  set（String key， Object obj）

		User user = new User("张飞","56");

		//user现在在栈顶位置

		valueStack1.push(user);

		//创建map集合 map压入栈顶

		valueStack1.set("name", "关羽");

		return SUCCESS;

	}

}

package com.itheima.struts2.valuestack;

import java.util.ArrayList;

import java.util.List;

import org.apache.struts2.ServletActionContext;

import com.itheima.struts2.domain.User;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.util.ValueStack;

/**

 * 获取值栈的数据

 * @author ZWT

 *

 */

public class ValueStackDemo5 extends ActionSupport{

	@SuppressWarnings("unused")

	@Override

	public String execute() throws Exception {

		ValueStack valueStack1 = ActionContext.getContext().getValueStack();

		//向值栈中保存一个对象 获取出来

		User user = new User("张飞","123");

		valueStack1.push(user);

		//保存集合

		List<User> list = new ArrayList<User>();

		list.add(new User("aaa","111"));

		list.add(new User("bbb","222"));

		list.add(new User("ccc","333"));

		valueStack1.set("list", list);

		//往context中存

		ServletActionContext.getRequest().setAttribute("name", "www");

		ServletActionContext.getRequest().getSession().setAttribute("name", "eee");

		ServletActionContext.getServletContext().setAttribute("name", "rrr");

		return SUCCESS;

	}

}

<?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="demo1" extends="struts-default" namespace="/">

		<action name="valueStackDemo1" class="com.itheima.struts2.valuestack.ValueStackDemo1">

			<result>/demo1/success.jsp</result>

		</action>

		<action name="valueStackDemo2" class="com.itheima.struts2.valuestack.ValueStackDemo2">

		</action>

		<action name="valueStackDemo3" class="com.itheima.struts2.valuestack.ValueStackDemo3">

			<result>/demo1/success.jsp</result>

		</action>

		<action name="valueStackDemo4" class="com.itheima.struts2.valuestack.ValueStackDemo4">

			<result>/demo1/success.jsp</result>

		</action>

		<action name="valueStackDemo5" class="com.itheima.struts2.valuestack.ValueStackDemo5">

			<result>/demo1/success2.jsp</result>

		</action>

	</package>

</struts>

<?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>

	<!-- 配置Struts2的常量 -->

	<constant name="struts.action.extension" value="action"/>

	<!--开启静态方法访问  -->

	<constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>

	<include file="com/itheima/struts2/valuestack/struts_demo1.xml"></include>

</struts>

　　 Struts2学习第3天--OGNL、EL、值栈-LMLPHP

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<%@taglib uri="/struts-tags" prefix="s" %>

<%String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ request.getContextPath();

			pageContext.setAttribute("basePath", basePath);%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>OGNL在Struts2环境中的入门</h1>

<h3>调用对象的方法</h3>

<s:property value="'struts'.length()"/>

<h3>调用对象的静态方法</h3>

<s:property value="@java.lang.Math@random()"/>

</body>

</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

 <%@taglib uri="/struts-tags" prefix="s" %>

<%String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ request.getContextPath();

			pageContext.setAttribute("basePath", basePath);%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>查看值栈的内部结构</h1>

<s:debug></s:debug>

<!-- 方式1获取 利用action在值栈中的特性 -->

<%-- <s:property value="user.username"/>

<s:property value="user.password"/> --%>

<!-- 方式2获取 利用valuestack本身方法 -->

<s:property value="username"/>

<s:property value="password"/>

<s:property value="name"/>

</body>

</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

 <%@taglib uri="/struts-tags" prefix="s" %>

<%String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ request.getContextPath();

			pageContext.setAttribute("basePath", basePath);%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>查看值栈的内部结构</h1>

<s:debug></s:debug>

<!--获取对象的属性 -->

<s:property value="username"/>

<s:property value="password"/>

<!-- 获取集合当中的数据 -->

<s:property value="list[0].username"/>

<s:property value="list[0].password"/>

<s:property value="list[1].username"/>

<s:property value="list[1].password"/>

<s:property value="list[2].username"/>

<s:property value="list[2].password"/>

<!-- 获取context中的数据 -->

<s:property value="#request.name"/>

<s:property value="#session.name"/>

<s:property value="#application.name"/>

<hr>

${ username }

</body>

</html>

　　 Struts2学习第3天--OGNL、EL、值栈-LMLPHP

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<%@taglib uri="/struts-tags" prefix="s" %>

<%String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ request.getContextPath();

			pageContext.setAttribute("basePath", basePath);%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>#号的用法</h1>

<h3>用途1：获取context的数据</h3>

<%

	request.setAttribute("name","李兵");

	%>

<s:property value="#request.name"/>

<h3>构建map集合</h3>

<!-- list  i只要定义 context中也有-->

<s:iterator var="i" value="{'aa','bb','cc'}">

	<s:property value="i"/>--<s:property value="#i"/><br>

</s:iterator>

<!-- map -->

<s:iterator  var="entry" value="#{'aa':'11','bb':'22','cc':'33' }">

	<s:property value="key"/>--<s:property value="value"/><br>

	<s:property value="#entry.key"/>--<s:property value="#entry.value"/><br>

</s:iterator>

<hr>

<!-- value值 和 外面的‘男’ 一样就用list  不然用map -->

<%-- 性别：<input type="radio" name="sex1" value="男">男

<input type="radio" name="sex1" value="女">女

<hr>

<s:radio list="{'男','女'}" name="sex2" label="姓名" /> --%>

<hr>

性别：<input type="radio" name="sex1" value="1">男

<input type="radio" name="sex1" value="2">女

<hr>

<s:radio list="#{'1':'男','2':'女'}" name="sex2" label="姓名" />

</body>

</html>

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<%@taglib uri="/struts-tags" prefix="s" %>

<%String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()+ request.getContextPath();

			pageContext.setAttribute("basePath", basePath);%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h1>%号的用法</h1>

<h3></h3>

<%

	request.setAttribute("name", "张飞");

%>

<s:property value="#request.name"/><br>

姓名：<s:textfield name="name" value="%{#request.name}"></s:textfield><br>

<s:property value="%{'#request.name'}"/><br>

</body>

</html>