ongl 表达式

struts.xml简单配置

<!-- （默认false）设置ognl表达式是否支持静态方法 -->
    <constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>
    <package name="ognl" namespace="/ognl" extends="struts-default">
        <action name="ognl" class="com.ouc.wkp.action.OgnlAction">
            <result>/ognl.jsp</result>
        </action>
    </package>

struts.xml

记得打开

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

package com.ouc.wkp.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 org.apache.commons.chain.Catalog;

import com.opensymphony.xwork2.ActionSupport;
import com.ouc.wkp.model.Cat;
import com.ouc.wkp.model.Dog;
import com.ouc.wkp.model.User2;

//user.xxx只有传，才会构造，想初始化domain model，可以自己new，也可以传参数值
//但这时候要有参数为空的构造方法
//
public class OgnlAction extends ActionSupport {
    private String password;
    private String username;
    private User2 user;
    private Cat cat;
    private Map<String, Dog> dogMap = new HashMap<String, Dog>();
    private Set<Dog> dogs = new HashSet<Dog>();
    private List<User2> users = new ArrayList<User2>();

    public Cat getCat() {
        return cat;
    }

    public void setCat(Cat cat) {
        this.cat = cat;
    }

    public User2 getUser() {
        return user;
    }

    public void setUser(User2 user) {
        this.user = user;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Map<String, Dog> getDogMap() {
        return dogMap;
    }

    public void setDogMap(Map<String, Dog> dogMap) {
        this.dogMap = dogMap;
    }

    public Set<Dog> getDogs() {
        return dogs;
    }

    public void setDogs(Set<Dog> dogs) {
        this.dogs = dogs;
    }

    public List<User2> getUsers() {
        return users;
    }

    public void setUsers(List<User2> users) {
        this.users = users;
    }

    public OgnlAction() {
        users.add(new User2(1));
        users.add(new User2(2));
        users.add(new User2(3));

        dogs.add(new Dog("dog1"));
        dogs.add(new Dog("dog2"));
        dogs.add(new Dog("dog3"));

        dogMap.put("dog100", new Dog("dog100"));
        dogMap.put("dog101", new Dog("dog101"));
        dogMap.put("dog102", new Dog("dog102"));
    }

    @Override
    public String execute() throws Exception {
        return SUCCESS;
    }

    public String m() {
        return "mmmmm";
    }
}

OgnlAction.java

package com.ouc.wkp.model;
//user.xxx只有传，才会构造，想初始化domain model，可以自己new，也可以传参数值
//但这时候要有参数为空的构造方法
public class User2 {
    private int age=8;

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public User2(){
//        System.out.println("user constructor");
    }

    public User2(int age){
        this.age=age;
    }

    @Override
    public String toString() {
        return "user"+age;
    }
}

User2.java

package com.ouc.wkp.model;

public class Cat {
    private Dog friend;

    public Dog getFriend() {
        return friend;
    }

    public void setFriend(Dog friend) {
        this.friend = friend;
    }

    public String miaomiao(){
        return "miaomiao";
    }

//    public Cat(){
//
//    }
//
//    public Cat(Dog friend){
//        this.friend=friend;
//    }
//
//    @Override
//    public String toString() {
//        return "cat"+friend;
//    }
}

Cat.java

package com.ouc.wkp.model;

public class Dog {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Dog(){

    }

    public Dog(String name){
        super();
        this.name=name;
    }

    @Override
    public String toString() {
        return "dog"+name;
    }
}

Dog.java

然后就是比较核心的ognl.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'ognl.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

</head>

<body>
    <s:debug></s:debug>
    This is ognl.jsp
    <br> 访问值栈中的action的普通属性：username=
    <s:property value="username" />
    <br /> 访问值栈中对象的普通属性(get set 方法)
    <s:property value="user.age" />
    <br /> 访问值栈中对象的普通属性(get set 方法)
    <s:property value="cat.friend.name" />
    <br /> 访问值栈中对象的普通方法
    <s:property value="password.length()" />
    <br /> 访问值栈中对象的普通方法
    <s:property value="cat.miaomiao()" />
    <br /> 访问静态方法:
    <s:property value="@com.ouc.wkp.action.S@s()" />
    <br /> 访问静态属性:
    <s:property value="@com.ouc.wkp.action.S@STR" />
    <br /> 访问Math类的静态方法:
    <s:property value="@@max(2,3)" />
    <br /> 访问普通类的构造方法:
    <s:property value="new com.ouc.wkp.model.User2(10)" />
    <br /> 访问List:
    <s:property value="users" />
    <br /> 访问List中某个元素:
    <s:property value="users[1]" />
    <br /> 访问List中元素某个属性的集合:
    <s:property value="users.{age}" />
    <br /> 访问List中元素某个属性的集合中的特定值:
    <s:property value="users.{age}[0]" />
    <br /> |
    <s:property value="users[0].age" />
    <br /> 访问Set:
    <s:property value="dogs" />
    <br /> 访问Set中某个元素:
    <s:property value="dogs[1]" />
    <br /> 访问Map:
    <s:property value="dogMap" />
    <br /> 访问Map中某个元素:
    <s:property value="dogMap.dog101" />
    <br /> |
    <s:property value="dogMap['dog101']" />
    <br /> |
    <s:property value="dogMap[\"dog101\"]" />
    <br /> 访问Map中所有的key:
    <s:property value="dogMap.keys" />
    <br /> 访问Map中所有的value:
    <s:property value="dogMap.values" />
    <br /> 访问容器的大小：
    <s:property value="dogMap.size()" />
    <br /> |
    <s:property value="users.size" />
    <br /> 投影（过滤）:
    <s:property value="users.{?#this.age==1}[0]" />
    <br /> 投影:
    <s:property value="users.{^#this.age>1}.{age}" />
    <br /> 投影:
    <s:property value="users.{$#this.age>1}.{age}" />
    <br /> 投影:
    <s:property value="users.{$#this.age>1}.{age}==null" />
    <br /> []:
    value stack从上往下数<s:property value="[0].username" />
</body>
</html>

ognl.jsp

输入网址

http://localhost:8081/maShiBing/ognl/ognl?password=p&username=u&user.age=9&cat.friend.name=fuck

运行结果为