Ognl访问数组、List和Map_ognl 数组

数组

package com.xs;

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

public class OgnlAarray {

	/**
	 * @param args
	 * @throws OgnlException 
	 */
	public static void main(String[] args) throws OgnlException {
		User user0 = new User();
		user0.setPassword("word0");
		user0.setUsername("user0");
		User user1 = new User();
		user1.setPassword("word1");
		user1.setUsername("user1");
		User[] users = {user0, user1};
		OgnlContext context = new OgnlContext();
		context.put("users", users);
		context.setRoot(users);
		System.out.println(Ognl.getValue("length", context, context.getRoot()));
		System.out.println(Ognl.getValue("[0].username", context, context.getRoot()));
		System.out.println(Ognl.getValue("[1].password", context, context.getRoot()));
		
	}
}

输出：

2
user0
word1

List

package com.xs;

import java.util.ArrayList;
import java.util.List;

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

public class OgnlList {
	public static void main(String[] args) throws OgnlException{
		User user0 = new User();
		user0.setPassword("word0");
		user0.setUsername("user0");
		User user1 = new User();
		user1.setPassword("word1");
		user1.setUsername("user1");
		List<User> list = new ArrayList<User>();
		list.add(user0);
		list.add(user1);
		OgnlContext context = new OgnlContext();
		context.put("list", list);
		context.setRoot(list);
		System.out.println(Ognl.getValue("size", context, context.getRoot()));
		System.out.println(Ognl.getValue("[0].username", context, context.getRoot()));
		System.out.println(Ognl.getValue("[1].username", context, context.getRoot()));
	}
}

输出：

2
user0
user1

Map

package com.xs;

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

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

public class OgnlMap {

	/**
	 * @param args
	 * @throws OgnlException 
	 */
	public static void main(String[] args) throws OgnlException {
		User user0 = new User();
		user0.setPassword("word0");
		user0.setUsername("user0");
		
		User user1 = new User();
		user1.setPassword("word1");
		user1.setUsername("user1");
		
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("u0", user0);
		map.put("u1", user1);
		
		OgnlContext context = new OgnlContext();
		context.put("map", map);
		context.setRoot(map);
		
		System.out.println(Ognl.getValue("size", context, context.getRoot()));
		System.out.println(Ognl.getValue("u0.username", context, context.getRoot()));
		System.out.println(Ognl.getValue("u1.username", context, context.getRoot()));
	}

}

输出：

2
user0
user1

User类：

class User{
	private String username;
	private String password;
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	
}

疑问？

ArrayList和HashMap的字段size不是public的，也没有getter方法（访问size字段的方法为size()，跟字段名一样，对于普通对象是不能这样访问的），但是能通过size访问。

猜测：Ognl对集合做了特殊处理。