Struts2(九)OGNL标签一与Struts2标签

2019-11-14 23:32:25

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Struts2(九)OGNL标签一与Struts2标签一、什么是OGNL

Object Graph Navigation Language对象图导航语言。

是Struts2默认的表达式语言，开源，功能更强大。和EL表达式有点相似

存取对象的属性，调用对象的方法

访问静态方法，静态属性

访问值栈及Stack Context

支持赋值、运算操作、字段类型转化等。

二、简单例子

导入所需要的struts2的包

web.xml增加struts2过滤器

<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>

实体类

package com.pb.entity;/* * 街道实体类 */public class Street {    private int streetId;            //街道ID    private String streetName;    //街道名称            public Street() {        super();        // TODO Auto-generated constructor stub    }    public Street(int streetId, String streetName) {        super();        this.streetId = streetId;        this.streetName = streetName;    }    public int getStreetId() {        return streetId;    }    public String getStreetName() {        return streetName;    }    public void setStreetId(int streetId) {        this.streetId = streetId;    }    public void setStreetName(String streetName) {        this.streetName = streetName;    }            }

package com.pb.entity;/* * 房子实体类 */public class Hourse {        private int hourseId;  //房屋ID    private String hourseName;    //房屋名称    private Street street;            //房屋所在街道            public Hourse() {        super();        // TODO Auto-generated constructor stub    }    public Hourse(int hourseId, String hourseName, Street street) {        super();        this.hourseId = hourseId;        this.hourseName = hourseName;        this.street = street;    }    public int getHourseId() {        return hourseId;    }    public String getHourseName() {        return hourseName;    }    public Street getStreet() {        return street;    }    public void setHourseId(int hourseId) {        this.hourseId = hourseId;    }    public void setHourseName(String hourseName) {        this.hourseName = hourseName;    }    public void setStreet(Street street) {        this.street = street;    }    }

HourseAction

package com.pb.web.action;import com.opensymphony.xwork2.ActionSupport;import com.pb.entity.Hourse;import com.pb.entity.Street;public class HourseAction extends ActionSupport {        private Hourse hourse;        @Override        public String execute() throws Exception {            //声明街道对象            Street street =new Street(001,"南新路");            hourse=new Hourse(11,"一房一厅",street);            return SUCCESS;        }        public Hourse getHourse() {            return hourse;        }        public void setHourse(Hourse hourse) {            this.hourse = hourse;        }                }

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>    <constant name="struts.enable.DynamicMethodInvocation" value="false" />    <constant name="struts.devMode" value="true" />    <package name="default" namespace="/" extends="struts-default">    <action name="hourse" class="com.pb.web.action.HourseAction">    <result name="success">    /ognl1.jsp    </result>    </action>    </package></struts>

ognl1.jsp

<%@ 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>OGNL一</title></head><body>房屋的名称：<s:property value="hourse.hourseName"/>房屋的街道名称:<s:property value="hourse.street.streetName"/><s:debug/></body></html>

在地址栏中输入

http://localhost:8080/OGNLDemo1/hourse.action

发生页面跳转，并取出其中的值

三、访问值栈中的值

四、访问List 、Map、Set

struts.xml

    <action name="ognl" class="com.pb.web.action.OgnlAction">    <result name="success">    /ognllist.jsp    </result>    </action>

ognllistAction

package com.pb.web.action;import java.util.ArrayList;import java.util.HashMap;import java.util.HashSet;import java.util.List;import java.util.Map;import java.util.Set;import com.opensymphony.xwork2.ActionSupport;import com.pb.entity.Street;public class OgnlAction extends ActionSupport {    /**     *      */    private static final long serialVersionUID = 1L;    private List<Street> streetList;    private Map<String, Street> streetMap;    private Set <Street> streetSet;    public List<Street> getStreetList() {        return streetList;    }    public void setStreetList(List<Street> streetList) {        this.streetList = streetList;    }    public Map<String, Street> getStreetMap() {        return streetMap;    }    public void setStreetMap(Map<String, Street> streetMap) {        this.streetMap = streetMap;    }    public Set<Street> getStreetSet() {        return streetSet;    }    public void setStreetSet(Set<Street> streetSet) {        this.streetSet = streetSet;    }            @Override    public String execute() throws Exception {        streetList=new ArrayList<Street>();        streetList.add(new Street(1, "高新南一路"));        streetList.add(new Street(2, "高新南二路"));        streetList.add(new Street(3, "高新南三路"));        streetMap=new HashMap<String,Street>();        streetMap.put("k1", new Street(4, "高新南四路"));        streetMap.put("k2", new Street(5, "高新南五路"));        streetMap.put("k3", new Street(6, "高新南六路"));        streetSet =new HashSet<Street>();        streetSet.add(new Street(7, "高新南七路"));        streetSet.add(new Street(8, "高新南八路"));        streetSet.add(new Street(9, "高新南九路"));        return SUCCESS;    }            }

jsp页页

<%@ 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>OGNL一</title></head><body><h1>List</h1>访问List<s:property value="streetList" /><br/>访问List中第一个元素:<s:property value="streetList[0].streetName" /><br/>List中的大小:<s:property value="streetList.size()" /><br/>List是否为空:<s:property value="streetList.isEmpty()" /><br/>自定义集合List:<s:property value="{1,2,3,4,5}" /><br/>自定义集合List访问第一个元素:<s:property value="{1,2,3,4,5}[0]" /><br/><hr/><h1>Map</h1>访问Map<s:property value="streetMap" /><br/>访问Map中第一个元素:<s:property value="streetMap['k1'].streetName" />|<s:property value="streetMap.k1.streetName"/><br/>访问Map 中所有key:<s:property value="streetMap.keys" /><br/>访问Map 中所有values:<s:property value="streetMap.values" /><br/>Map中的大小:<s:property value="streetMap.size()" /><br/>Map是否为空:<s:property value="streetMap.isEmpty()" /><br/>自定义集合Map:<s:property value="#{'k1':'v1','k2':'v2','k3':'v3'}" /><br/>自定义集合Mapt访问第一个元素:<s:property value="#{'k1':'v1','k2':'v2','k3':'v3'}['k1']" />|<s:property value="#{'k1':'v1','k2':'v2','k3':'v3'}.k1" /><br/><hr/><h1>Set</h1>访问Set<s:property value="streetSet" /><br/>访问Set中第一个元素:<s:property value="streetSet.toArray()[0].streetName" />|<s:property value="streetSet.toArray()[0].streetName"/><br/>Set中的大小:<s:property value="streetSet.size()" /><br/>Set是否为空:<s:property value="streetSet.isEmpty()" /><br/><hr/><s:debug/></body></html>

在页面中输入：http://localhost:8080/OGNLDemo1/ognl.action访问

五、访问静态方法和投影

5.1、访问静态方法和静态属性

package com.pb.demo;public class Demo {public final static String STR="STATIC STR";public static String staticMethod(){String info="Demo Static Method";return info;}}

在ognl2.jsp 中可以通过如下代码访问该类的静态属性以及静态方法：

<%@taglib uri="/struts-tags" prefix="s"%><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><h1>OGNL 对象图导航语言</h1>调用静态方法：<s:property value="@com.pb.demo.Demo@staticMethod()"/> <br>调用静态常量：<s:property value="@com.pb.demo.Demo@STR"/><s:debug/></body></html>

struts.xml

//开启静态方法<constant name="struts.ognl.allowStaticMethodaccess" value="true" />

其中<constant>常量你可以去default.properties 文件中查找并复制使用。

5.2、访问投影

选择就是过滤满足选择条件的集合元素。选择操作的语法是：collection.{X YYY},其中X是一个选择操作符，后面则是选择用的逻辑表达式，而选择操作符有三种：?选择满足条件的所有元素^选择满足条件的第一个元素$选择满足条件的最后一个元素

package com.pb.entity;/* * 用户名 */public class User {    private Integer age;    private String name;    private String pasWord;    public User() {        super();        // TODO Auto-generated constructor stub    }    public User(String name, String pasword, Integer age) {        super();        this.name = name;        this.pasword = pasword;        this.age = age;    }    public Integer getAge() {        return age;    }    public String getName() {        return name;    }    public String getPasword() {        return pasword;    }    public void setAge(Integer age) {        this.age = age;    }    public void setName(String name) {        this.name = name;    }    public void setPasword(String pasword) {        this.pasword = pasword;    }}

package com.pb.web.action;import java.util.ArrayList;import java.util.List;import com.opensymphony.xwork2.ActionSupport;import com.pb.entity.User;public class UserAction extends ActionSupport {    private User user;    private List<User> users=new ArrayList<User>();    public User getUser() {        return user;    }    public void setUser(User user) {        this.user = user;    }    public List<User> getUsers() {        return users;    }    public void setUsers(List<User> users) {        this.users = users;    }    @Override    public String execute() throws Exception {        User u1 = new User();        u1.setName("zhangsan");        u1.setPasword("zhangsan");        u1.setAge(10);        this.users.add(u1);        User u2 = new User();        u2.setName("lisi");        u2.setPasword("lisi");        u2.setAge(23);        this.users.add(u2);        User u3 = new User();        u3.setName("wangwu");        u3.setPasword("wangwu");        u3.setAge(22);        this.users.add(u3);        return SUCCESS;    }        }

struts.xml

<package name="default" namespace="/" extends="struts-default">      <action name="login" class="com.pb.web.action.UserAction">    <result name="success">    /ognl.jsp    </result>    </action>     </package>

jsp页面

<%@taglib prefix="s" uri="/struts-tags" %><!-- 年龄大于18 的所有用户的姓名 -->集合元素过滤：<s:property value="users.{?#this.age>18}.{name}"/><br/><!-- 年龄大于18 的所有用户的第一个用户的姓名 -->集合元素过滤：<s:property value="users.{^#this.age>18}.{name}"/><br/><!-- 年龄大于18 的所有用户的最后一个用户的姓名 -->集合元素过滤：<s:property value="users.{$#this.age>18}.{name}"/><br/>

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