layout: post
title: OGNL
subtitle: OGNL
date: 2018-05-31
author: ZL
header-img: img/20180531.jpg
catalog: true
tags:
- OGNL

OGNL（对象视图导航语言）

${user.addr.name} 这种写法就叫对象视图导航.
OGNL不仅仅可以视图导航.支持比EL表达式更加丰富的功能.

使用

导包

在struts2的包中就已经包含了OGNL的包ognl-3.0.6.jar

准备bean类User

package zl.bean;
public class User {
    private String name;
    private Integer age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public User() {
        super();
    }
    public User(String name, Integer age) {
        super();
        this.name = name;
        this.age = age;
    }
}

取出root和context的属性值

@Test
public void fun1() throws OgnlException{
  //准备root
  User u1 = new User("qqq",18);
  
  //准备context
  Map<String,User> context = new HashMap<String,User>();
  context.put("user1", new User("sss", 19));
  context.put("user2", new User("yyy", 20));
  
  //设置root和context
  OgnlContext ognl = new OgnlContext();
  ognl.setRoot(u1);
  ognl.setValues(context);
  
  //取出root中的数据,直接写属性名
  String name = (String) Ognl.getValue("name", ognl, ognl.getRoot());
  Integer age = (Integer) Ognl.getValue("age", ognl, ognl.getRoot());
  System.out.println(name);
  System.out.println(age);
  
  //取出context中的属性值
  //#代表从context中取值
  String user1name = (String) Ognl.getValue("#user1.name", ognl, ognl.getRoot());
  Integer user1age = (Integer) Ognl.getValue("#user1.age", ognl, ognl.getRoot());
  System.out.println(user1name+user1age);
}

修改root和context的属性值

@Test
public void fun2() throws OgnlException{
  //准备root
  User u1 = new User("qqq",18);
  
  //准备context
  Map<String,User> context = new HashMap<String,User>();
  context.put("user1", new User("sss", 19));
  context.put("user2", new User("yyy", 20));
  
  //设置root和context
  OgnlContext ognl = new OgnlContext();
  ognl.setRoot(u1);
  ognl.setValues(context);
  
  //修改root的name属性值
  Ognl.getValue("name = 'aaaa'", ognl, ognl.getRoot());
  String rootname = (String) Ognl.getValue("name", ognl, ognl.getRoot());
  System.out.println(rootname);
  
  //修改user1的name和age属性值
  Ognl.getValue("#user1.name = 'bbbb'", ognl, ognl.getRoot());
  Ognl.getValue("#user1.age = 99", ognl, ognl.getRoot());
  String user1name = (String) Ognl.getValue("#user1.name", ognl, ognl.getRoot());
  Integer user1age = (Integer) Ognl.getValue("#user1.age", ognl, ognl.getRoot());
  System.out.println(user1name+user1age);
}

调用user的方法

@Test
public void fun3() throws OgnlException{
  //准备root
  User u1 = new User("qqq",18);
  
  //准备context
  Map<String,User> context = new HashMap<String,User>();
  context.put("user1", new User("sss", 19));
  context.put("user2", new User("yyy", 20));
  
  //设置root和context
  OgnlContext ognl = new OgnlContext();
  ognl.setRoot(u1);
  ognl.setValues(context);
  
  //从root中调用user对象的getName方法。
  String rootname = (String) Ognl.getValue("getName()", ognl, ognl.getRoot());
  System.out.println(rootname);
  
  //从root中调用user对象的setName方法。
  Ognl.getValue("setName('jjj')", ognl, ognl.getRoot());
  String rootname2 = (String) Ognl.getValue("getName()", ognl, ognl.getRoot());
  System.out.println(rootname2);
}

调用静态的方法和属性

@Test
public void fun4() throws OgnlException{
  //准备root
  User u1 = new User("qqq",18);
  
  //准备context
  Map<String,User> context = new HashMap<String,User>();
  context.put("user1", new User("sss", 19));
  context.put("user2", new User("yyy", 20));
  
  //设置root和context
  OgnlContext ognl = new OgnlContext();
  ognl.setRoot(u1);
  ognl.setValues(context);
  
  //访问静态方法,属性
  String xxx = (String) Ognl.getValue("@zl.ognl.XXX@xxx('1234567')", ognl, ognl.getRoot());
  Double pi = (Double) Ognl.getValue("@java.lang.Math@PI", ognl, ognl.getRoot());
  System.out.println(xxx);
  System.out.println(pi);
}

创建list对象,操作list

@Test
public void fun5() throws OgnlException{
  //准备root
  User u1 = new User("qqq",18);
  
  //准备context
  Map<String,User> context = new HashMap<String,User>();
  context.put("user1", new User("sss", 19));
  context.put("user2", new User("yyy", 20));
  
  //设置root和context
  OgnlContext ognl = new OgnlContext();
  ognl.setRoot(u1);
  ognl.setValues(context);
  
  //创建list，取出list的某个元素
  Integer size = (Integer)Ognl.getValue("{'aaa','bbb','ccc','ddd'}.size()", ognl, ognl.getRoot());
  String first = (String)Ognl.getValue("{'aaa','bbb','ccc','ddd'}[0]", ognl, ognl.getRoot());
  String second = (String)Ognl.getValue("{'aaa','bbb','ccc','ddd'}.get(1)", ognl, ognl.getRoot());
  System.out.println(size);
  System.out.println(first);
  System.out.println(second);
  
  List list = (List) Ognl.getValue("{'aaa','bbb','ccc','ddd'}", ognl, ognl.getRoot());
  System.out.println(list);
}

创建map对象，操作map

@Test
    public void fun6() throws OgnlException{
        //准备root
        User u1 = new User("qqq",18);
        
        //准备context
        Map<String,User> context = new HashMap<String,User>();
        context.put("user1", new User("sss", 19));
        context.put("user2", new User("yyy", 20));
        
        //设置root和context
        OgnlContext ognl = new OgnlContext();
        ognl.setRoot(u1);
        ognl.setValues(context);
        
        //创建map,取出某个元素
        Integer size = (Integer)Ognl.getValue("#{'name':'bbb','age':18}.size()", ognl, ognl.getRoot());
        String name = (String)Ognl.getValue("#{'name':'bbb','age':18}['name']", ognl, ognl.getRoot());
        String name2 = (String)Ognl.getValue("#{'name':'bbb','age':18}.get('name')", ognl, ognl.getRoot());
        System.out.println(size);
        System.out.println(name);
        System.out.println(name2);
        
        Map map = (Map)Ognl.getValue("#{'name':'bbb','age':18}", ognl, ognl.getRoot());
        System.out.println(map);
    }