所有的学习我们必须先搭建好Struts2的环境（1、导入对应的jar包，2、web.xml，3、struts.xml）
第一节：值栈简介
值栈是对应每个请求对象的一套内存数据的封装，Struts2 会给每个请求创建一个新的值栈。
值栈能够线程安全地为每个请求提供公共的数据存取服务。
第二节：OGNL 引入
OGNL 是对象图导航语言Object-Graph Navigation Language 的缩写，它是一种功能强大的表达式语言。
OGNL 访问ValueStack 数据
<s:property value=”account” />
注：这里要添加<%@taglib prefix="s" uri="/struts-tags" %>struts的标签库
OGNL 访问ActionContext 数据
访问某个范围下的数据要用#
#parameters 请求参数request.getParameter(...)；
#request 请求作用域中的数据request.getAttribute(...)；
#session 会话作用域中的数据session.getAttribute(...)；
#application 应用程序作用域中的数据application.getAttribute(...)；
#attr 按照page request session application 顺序查找值
例子：
struts.xml
1 <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <package name="manage" namespace="/" extends="struts-default"> <action name="hello" class="com.wishwzp.action.HelloAction">
<result name="success" >success.jsp</result>
</action>
</package> </struts>
HelloAction.java
1 package com.wishwzp.action; import java.util.Map; import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.util.ValueStack; public class HelloAction extends ActionSupport{ /**
*
*/
private static final long serialVersionUID = 1L; @Override
public String execute() throws Exception {
// 获取ActionContext
ActionContext actionContext=ActionContext.getContext();
// 获取狭义上的值栈
// 值栈是用来存储数据的
ValueStack valueStack=actionContext.getValueStack();
valueStack.set("name", "张三(valueStack)");
valueStack.set("age", 11); Map<String, Object> session=actionContext.getSession();
session.put("name", "王五(session)");
session.put("age", 13); Map<String, Object> application=actionContext.getApplication();
application.put("name", "赵六(application)");
application.put("age", 14);
return SUCCESS;
}
}
success.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags" %>
<!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>
<%
request.setAttribute("name", "李四(request)");
request.setAttribute("age", "12");
%>
</head>
<body>
获取狭义上的值栈数据：<s:property value="name"/>
<s:property value="age"/><br/>
请求参数：<s:property value="#parameters.name"/>
<s:property value="#parameters.age"/><br/>
request：<s:property value="#request.name"/>
<s:property value="#request.age"/><br/>
session：<s:property value="#session.name"/>
<s:property value="#session.age"/><br/>
application：<s:property value="#application.name"/>
<s:property value="#application.age"/><br/>
attr取值：<s:property value="#attr.name"/>
<s:property value="#attr.age"/><br/>
</body>
</html>
url:http://localhost:8080/Struts2Chap04/hello?name=ssss&age=23
结果：
第三节：OGNL 访问复杂对象
1，访问javaBean 对象；
2，访问集合对象；
3，访问Map 对象；
例子：
struts.xml
1 <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <package name="manage" namespace="/" extends="struts-default"> <action name="hello" class="com.wishwzp.action.HelloAction">
<result name="success" >success.jsp</result>
</action>
</package> </struts>
Student.java
1 package com.wishwzp.model; public class Student { private String name;
private int age; public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(String name, int age) {
super();
this.name = name;
this.age = age;
} public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
} }
HelloAction.java
1 package com.wishwzp.action; import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map; import com.wishwzp.model.Student;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.util.ValueStack; public class HelloAction extends ActionSupport{ /**
*
*/
private static final long serialVersionUID = 1L; //访问javaBean对象,并get...和set...
private Student student; //访问集合对象,并get...和set...
private List<Student> students; //访问Map对象,并get...和set...
private Map<String,Student> studentMap; public Map<String, Student> getStudentMap() {
return studentMap;
} public void setStudentMap(Map<String, Student> studentMap) {
this.studentMap = studentMap;
} public List<Student> getStudents() {
return students;
} public void setStudents(List<Student> students) {
this.students = students;
} public Student getStudent() {
return student;
} public void setStudent(Student student) {
this.student = student;
} @Override
public String execute() throws Exception { //javaBean对象
student=new Student("小扒", 12); //集合对象
students=new ArrayList<Student>();
students.add(new Student("老九",13));
students.add(new Student("老十",14)); //Map对象
studentMap=new HashMap<String,Student>();
studentMap.put("goodStudent", new Student("学霸",20));
studentMap.put("badStudent", new Student("学渣",19));
return SUCCESS;
} }
success.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags" %>
<!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>
ognl访问javaBean对象：<s:property value="student.name"/>
<s:property value="student.age"/><br/> ognl访问List集合：<s:property value="students[0].name"/>
<s:property value="students[0].age"/><br/>
<s:property value="students[1].name"/>
<s:property value="students[1].age"/><br/> ognl访问Map：<s:property value="studentMap['goodStudent'].name"/>
<s:property value="studentMap['goodStudent'].age"/><br/>
<s:property value="studentMap['badStudent'].name"/>
<s:property value="studentMap['badStudent'].age"/><br/>
</body>
</html>
url访问：http://localhost:8080/Struts2Chap04/hello
结果：
第四节：OGNL 访问静态方法和属性
1，访问静态属性；
2，访问静态方法；需要在struts.xml加上<constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>
例子：
struts.xml
1 <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant> <package name="manage" namespace="/" extends="struts-default"> </package> </struts>
MyStatic.java
1 package com.wishwzp.common; public class MyStatic { //静态属性
public static final String str="Struts2开心学习"; //静态方法
public static String printUrl(){
System.out.println("http://www.baidu.com");
return "http://www.baidu.com";
}
}
ognl_static.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags" %>
<!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>
访问静态属性： <s:property value="@com.wishwzp.common.MyStatic@str"/><br/>
访问静态方法：<s:property value="@com.wishwzp.common.MyStatic@printUrl()"/>
</body>
</html>
url:http://localhost:8080/Struts2Chap04/ognl_static.jsp
结果：