struts OGNL表达式

OGNLContext对象有两部分构成

　　一部分是ROOT：可以放置任何对象作为ROOT

　　另外一部分Context：必须是Map形式（键值对）

　　

OGNL表达式操作

package cn.future.a_ognl;

import java.util.HashMap;
import java.util.Map;

import ognl.Ognl;
import ognl.OgnlContext;
import ognl.OgnlException;

import org.junit.Test;

import cn.future.domain.User;

public class Demo {
    
    @Test
    //取出Root中的值
    public void fun() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //取root中userRoot对象的name属性
        String name = (String) Ognl.getValue("name", oc, oc.getRoot());
        int age = (Integer) Ognl.getValue("age", oc, oc.getRoot());
        System.out.println(name);
        System.out.println(age);
    }
    
    @Test
    //取出Context中的值
    public void fun1() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //取User1对象的name属性
        String name = (String) Ognl.getValue("#user1.name", oc, oc.getRoot());
        int age = (Integer) Ognl.getValue("#user1.age", oc, oc.getRoot());
        System.out.println(name);
        System.out.println(age);
    }
    
    @Test
    //为属性赋值
    public void fun2() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //给Roog中userRoot对象的name属性赋值
        Ognl.getValue("name='grf'", oc, oc.getRoot());//赋值 有返回值，返回值是name的值
        String name = (String) Ognl.getValue("name='grf',name", oc, oc.getRoot());//即赋值又取值
        //给Context中user1的name属性赋值
        Ognl.getValue("#user1.name='grf'", oc, oc.getRoot());
    }
    
    @Test
    //为属性赋值(set get)
    public void fun3() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //给Roog中userRoot对象的name属性赋值
        Ognl.getValue("setName('grf')", oc, oc.getRoot());//赋值 返回值为null
        String name = (String) Ognl.getValue("getName()", oc, oc.getRoot());//即赋值又取值
        //给Context中user1的name属性赋值
        Ognl.getValue("#user1.setName('grf'),#user1.getName()", oc, oc.getRoot());
    }
    
    @Test
    //调用静态方法，或者静态属性
    public void fun4() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //给Roog中userRoot对象的name属性赋值
        Double pi = (Double) Ognl.getValue("@java.lang.Math@PI", oc, oc.getRoot());//赋值 返回值为null
        System.out.println(pi);
        
    }
    
    @Test
    //创建集合 list|map
    public void fun5() throws OgnlException{
        //OGNL表达式
        //准备ROOT
        User userRoot = new User("ms",25);
        //准备Context
        Map<String,User> contextMap = new HashMap<String, User>();
        contextMap.put("user1", new User("AAA",10));
        contextMap.put("user2", new User("BBB",11));
        //书写OGNL
        OgnlContext oc = new OgnlContext();
        oc.setRoot(userRoot);
        oc.setValues(contextMap);
        //OGNL取值
        //创建list
        Ognl.getValue("{'aaa','bbb','ccc','ddd'}", oc, oc.getRoot());
        Integer listSize = (Integer) Ognl.getValue("{'aaa','bbb','ccc','ddd'}.size()", oc, oc.getRoot());
        String listName = (String) Ognl.getValue("{'aaa','bbb','ccc','ddd'}[0]", oc, oc.getRoot());
        String listName1 = (String) Ognl.getValue("{'aaa','bbb','ccc','ddd'}.get(1)", oc, oc.getRoot());

        //创建map
        Ognl.getValue("#{'name':'ms','age',25}", oc, oc.getRoot());
        Integer mapSize = (Integer) Ognl.getValue("#{'name':'ms','age',25}.size()", oc, oc.getRoot());
        String mapName = (String) Ognl.getValue("#{'name':'ms','age',25}[name]", oc, oc.getRoot());
        Integer mapAge = (Integer) Ognl.getValue("#{'name':'ms','age',25}.get('age')", oc, oc.getRoot());
    }
}