陣列

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()));
		
	}
}


 

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()));
	}
}
 

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()));
	}

}
 

2
user0
user1

User類：

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;
	}
	
}

疑問？

ArrayList和HashMap的欄位size不是public的，也沒有getter方法（訪問size欄位的方法為size()，跟欄位名一樣，對於普通物件是不能這樣訪問的），但是能通過size訪問。

猜測：Ognl對集合做了特殊處理。