commons jexl 用例

import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.apache.commons.jexl2.Expression;
import org.apache.commons.jexl2.JexlContext;
import org.apache.commons.jexl2.JexlEngine;
import org.apache.commons.jexl2.MapContext;

public class ArrayTest {
    
    public static void test1(){
        JexlEngine jexl = new JexlEngine();
        JexlContext jc = new MapContext();
        
        List<Object> l = new LinkedList<Object>();
        l.add("Hello from location 0");
        Integer two = new Integer(2);
        l.add(two);
        l.add("abcd");
        l.add("xfc");
        
        
        Map<String,Object> map = new HashMap<String,Object>();
        map.put("key1","abcd");
        map.put("key2", 22);
        
        jc.set("array",l);
        jc.set("map",map);
        jc.set("Arrays",Arrays.class);
        
        
        String[] strs = new String[]{
                "array.size()",
                "array[0]",
                "array[0].length()",
                "Arrays.asList(map.keySet().toArray())",
                "map['key1']",
                "map['key1'].length()"
        };
        
        for (String string : strs) {
            Expression e = jexl.createExpression(string);
            Object o = e.evaluate(jc);
            System.out.println(string+"..."+o);
        }
    }
    
    public static void main(String [] args){
        test1();
    }
}

 

jexl的版本：

<dependency>
	<groupId>org.apache.commons</groupId>
	<artifactId>commons-jexl</artifactId>
	<version>2.1.1</version>
</dependency>