Error in converting List to JSON in Java (4)
1. Error description
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/map/ListOrderedMapat net.sf.json.JSONObject.
(JSONObject.java:1450)at net.sf.json.util.CycleDetectionStrategy.
(CycleDetectionStrategy.java:37)at net.sf.json.JsonConfig.
(JsonConfig.java:65)at net.sf.json.JSONArray.fromObject(JSONArray.java:105)at com.you.model.ListToJSON.main(ListToJSON.java:29)Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.map.ListOrderedMapat java.net.URLClassLoader$1.run(URLClassLoader.java:366)at java.net.URLClassLoader$1.run(URLClassLoader.java:355)at java.security.AccessController.doPrivileged(Native Method)at java.net.URLClassLoader.findClass(URLClassLoader.java:354)at java.lang.ClassLoader.loadClass(ClassLoader.java:425)at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)at java.lang.ClassLoader.loadClass(ClassLoader.java:358)... 5 more
2. Error cause
/*** Convert List to JSON */package com. you. model; import java. util. arrayList; import java. util. list; import net. sf. json. JSONArray;/*** @ author YouHaiDong **/public class ListToJSON {/*** @ param args */public static void main (String [] args) {List
List = new ArrayList
(); List. add ("Spring"); list. add ("Summer"); list. add ("Autumn"); list. add ("Winter"); JSONArray jsonArray = JSONArray. fromObject (list); System. out. println ("List converted to JSON:" + jsonArray. toString ());}}
We can see from "Caused by: java. lang. ClassNotFoundException: org. apache. commons. collections. map. ListOrderedMap" that jar is missing.
3. Solution
Copy the commons-collections-3.1.jar to the lib directory