Struts2中使用OGNL

  链接:Struts标签库

OGNL(Object Graphic Navigatino Language)

OGNL称为对象图导航语言。以一个对象为根(起点),通过OGNL可以访问与这个对象关联的其它对象,正所谓“对象导航,顺藤摸瓜”

Struts2中使用OGNL

使用OGNL的jsp需要引入标签库:<%@taglib prefix="s" uri="/struts-tags"%>

struts.xml

<?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="p1" namespace="/" extends="struts-default">
<action name="m1Action" class="org.ah.s2.C1" method="m1">
<result name="success" type="dispatcher">
/inputMsg.jsp
</result>
</action>
</package>
</struts>

模型层:来个两级模型

Model.java

package org.ah.s2;

public class Model {
private String uname;
private M2 m2; public Model(String uname, M2 m2) {
this.uname = uname;
this.m2 = m2;
} public M2 getM2() {
return m2;
} public void setM2(M2 m2) {
this.m2 = m2;
} public String getUname() {
return uname;
} public void setUname(String uname) {
this.uname = uname;
}
}

M2.java

package org.ah.s2;

public class M2 {
public M2(String name2) {
this.name2 = name2;
} private String name2; public String getName2() {
return name2;
} public void setName2(String name2) {
this.name2 = name2;
}
}

Action:C1.java

package org.ah.s2;

import java.util.ArrayList;
import java.util.List; import org.apache.struts2.ServletActionContext; import ognl.Ognl;
import ognl.OgnlException; import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.util.ValueStack; public class C1 extends ActionSupport {
private Model m;
private List<Model> lstM; // ------------------------------------------------------------------
public Model getM() {
return m;
} public void setM(Model m) {
this.m = m;
} public List<Model> getLstM() {
return lstM;
} public void setLstM(List<Model> lstM) {
this.lstM = lstM;
} // ------------------------------------------------------------------
public String m1() {
ActionContext ac = ActionContext.getContext();
// 放入值栈外围
ac.put("msg", "out_value"); // 放入值栈
ValueStack valueStack = ac.getValueStack();
valueStack.set("msg", "vStack_value");// OK // 放入Application
ac.getApplication().put("msg", "hello application");
// 放入session
ac.getSession().put("msg", "hello session"); // 放入request(上面的ActionContext ac搞不定,需要ServletActionContext)
ServletActionContext.getRequest().setAttribute("msg", "hello request"); // 放置对象
m = new Model("吕布", new M2("方天画戟")); // 放置List
Model m1 = new Model("关羽", new M2("青龙偃月刀"));
Model m2 = new Model("张飞", new M2("丈八蛇矛枪"));
Model m3 = new Model("赵云", new M2("龙胆亮银枪"));
lstM = new ArrayList<Model>();
lstM.add(m1);
lstM.add(m2);
lstM.add(m3);
return "success";
} }

index.jsp核心代码

    <s:form action="m1Action" method="post">
<s:textfield name="msg" value="my input"></s:textfield>
<s:submit value="测试Struts控件传值"></s:submit>
</s:form>

回显页inputMsg.jsp核心代码

    1.值栈中的值:
<s:property value="msg" />
<hr>
2.值栈外围值:
<s:property value="#msg" />
<br> 3.
<s:property value="#parameters.msg" />取表单提交值
<br> 4.
<s:property value="#application.msg" />
<br> 5.
<s:property value="#session.msg" />
<br> 6.
<s:property value="#request.msg" />
<br> 7.
<s:property value="#attr.msg" /> 按page > request > session > application顺序访问其属性,取page的值只能用这个<br> 8.取对象
<s:property value="m.uname" />
<s:property value="m.m2.name2" />
<br> 9.取List
<!-- 用listValue指定显示的内容 -->
下拉列表:
<s:select list="lstM" listValue="uname" headerValue="缺省值">
</s:select>
<br> 下拉列表(自定义List):
<s:select list="#{'0':'男','1':'女'}" label="性别" headerValue="请选择性别" />
<br>
<br> 循环遍历:
<br>
<s:iterator value="lstM" var="per" status="sta">
<s:property value="#per.uname" />
<s:property value="#per.m2.name2" />
<br>
循环的次数为:<s:property value="#sta.count" />
<br>
循环的索引为:<s:property value="#sta.index" />
<br>
是否为奇数:<s:property value="#sta.odd" />
<s:if test="#sta.count==1">No.1</s:if>
<s:elseif test="#sta.count==2">No.2</s:elseif>
<s:else>No.3</s:else>

<br /> </s:iterator>
<br>
遍历set集合:(自定义的字符串不能是字符!至少加一个空格)
<br>
<s:set name="set" value="{'E ','ddddd','ccccc','bbbbb','aaaaa'}"></s:set>
<s:iterator value="#set" var="o">
<!-- ${o }<br/> -->
<s:property value="o" />
<br />
</s:iterator> <s:debug></s:debug>

直接点击提交,查看运行结果:

Struts2中使用OGNL

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