JSON JSON-lib Java Library

Introduction

 

JSON-lib (http://json-lib.sourceforge.net/)는 자바에서 beans, maps, collections, array 그리고 XML을 JSON 으로 변환하기 위해 사용하는 자바 라이브러리이다. 

• Javadoc
  • jdk1.3 : http://json-lib.sourceforge.net/apidocs/index.html
  • jdk1.5 : http://json-lib.sourceforge.net/apidocs/jdk15/index.html

 

 

 

Download

 

 

다음의 경로에서 다운로드 한다.

• http://sourceforge.net/projects/json-lib/files/json-lib/

 

 

Dependencies

 

JSON-lib는 아래의 패키지에 의존성을 가지고 있다.

• jakarta commons-lang 2.5
• jakarta commons-beanutils 1.8.0
• jakarta commons-collections 3.2.1
• jakarta commons-logging 1.1.1
• ezmorph 1.0.6

 

주의해야할 점은 common-lang 최신 버전(3.3.1)을 사용할 경우 org.apache.commons.lang.exception.NestableRuntimeException 이 발생하게 된다. 위의 경로에서 패키지를 다운 받아 등록하거나 pom.xml에 아래의 Dependency를 추가한다.

 

<dependency> <groupId>commons-lang</groupId> <artifactId>commons-lang</artifactId> <version>2.6</version> </dependency> <dependency> <groupId>commons-beanutils</groupId> <artifactId>commons-beanutils</artifactId> <version>1.8.3</version> </dependency> <dependency> <groupId>commons-collections</groupId> <artifactId>commons-collections</artifactId> <version>3.2.1</version> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.1.1</version> </dependency> <dependency> <groupId>net.sf.ezmorph</groupId> <artifactId>ezmorph</artifactId> <version>1.0.6</version> </dependency>

 

 

How to use json-lib

 

Array and Collection to JSON : 

import java.util.ArrayList; import java.util.List; import junit.framework.TestCase; import net.sf.json.JSONArray; public class JSONLibTest extends TestCase { public void testArrayCollection() { boolean[] boolArray = new boolean[]{true,false}; JSONArray jsonArray = JSONArray.fromObject( boolArray ); System.out.println( "boolArray : " + jsonArray ); List<String> list = new ArrayList<String>(); list.add("1"); list.add("second"); list.add("셋"); JSONArray jsonArray1 = JSONArray.fromObject( list ); System.out.println( "jsonArray1:" + jsonArray1 ); JSONArray jsonArray2 = JSONArray.fromObject( "['하나','2','third']" ); System.out.println( "jsonArray2:" + jsonArray2 ); } } //boolArray : [true,false] //jsonArray1:["1","second","셋"] //jsonArray2:["하나","2","third"]

 

Bean and Map to JSON : 

//Sample Bean import net.sf.json.JSONFunction; public class TestBean { private String name = "json"; private int num = 1; private char[] options = new char[]{ 'k', 'o', 'r' }; private String func1 = "function(i) { return this.options[i]; }"; private JSONFunction func2 = new JSONFunction(new String[]{"i"},"return this.options[i];"); public String getName() { return name; } public void setName(String name) { this.name = name; } public int getNum() { return num; } public void setNum(int num) { this.num = num; } public char[] getOptions() { return options; } public void setOptions(char[] options) { this.options = options; } public String getFunc1() { return func1; } public void setFunc1(String func1) { this.func1 = func1; } public JSONFunction getFunc2() { return func2; } public void setFunc2(JSONFunction func2) { this.func2 = func2; } }

 

import java.util.HashMap; import java.util.Map; import junit.framework.TestCase; import net.sf.json.JSONObject; public class JSONLibTest extends TestCase { public void testBeanMaps() { Map<String, Object> map = new HashMap<String, Object>(); map.put( "string", "jin" ); map.put( "bool", Boolean.TRUE ); map.put( "int", new Integer(1) ); map.put( "array", new String[]{"a","b"} ); map.put( "function", "function(i){ return this.arr[i]; }" ); JSONObject jsonObjectMap = JSONObject.fromObject( map ); System.out.println( "jsonObjectMap:" + jsonObjectMap ); JSONObject jsonObjectBean = JSONObject.fromObject( new TestBean() ); System.out.println( "jsonObjectBean:" + jsonObjectBean ); } } //jsonObjectMap:{"int":1,"string":"jin","bool":true,"function":function(i){ return this.arr[i]; },"array":["a","b"]} //jsonObjectBean:{"func1":function(i) { return this.options[i]; },"func2":function(i){ return this.options[i]; },"name":"json","num":1,"options":["k","o","r"]}

 

JSON to Beans : 

import java.lang.reflect.InvocationTargetException; import java.util.List; import junit.framework.TestCase; import net.sf.json.JSONArray; import net.sf.json.JSONObject; import org.apache.commons.beanutils.PropertyUtils; public class JSONLibTest extends TestCase { @SuppressWarnings("unchecked") public void testJsonToBeans() throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { String strJson = "{\"func1\":function(i) { return this.options[i]; },\"func2\":function(i){ return this.options[i]; },\"name\":\"json\",\"num\":1,\"options\":[\"k\",\"o\",\"r\"]}"; JSONObject jsonObjectJsonToBeans = JSONObject.fromObject( strJson ); Object beans = JSONObject.toBean( jsonObjectJsonToBeans ); assertEquals( jsonObjectJsonToBeans.get( "name" ), PropertyUtils.getProperty( beans, "name" ) ); assertEquals( jsonObjectJsonToBeans.get( "num" ), PropertyUtils.getProperty( beans, "num" ) ); assertEquals( jsonObjectJsonToBeans.get( "func1" ), PropertyUtils.getProperty( beans, "func1" ) ); assertEquals( jsonObjectJsonToBeans.get( "func2" ), PropertyUtils.getProperty( beans, "func2" ) ); @SuppressWarnings("deprecation") List<String> expected = JSONArray.toList(jsonObjectJsonToBeans.getJSONArray("options")); assertEquals( expected, (List<String>) PropertyUtils.getProperty(beans, "options") ); } }

 

Json to XML AND XML to JSON : 

XMLSerializer.write()와 XMLSerializer.read() 를 사용하여 XML을 JSON으로 JSON을 XML로 변환할 수 있다.

import junit.framework.TestCase; import net.sf.json.JSONArray; import net.sf.json.JSONObject; import net.sf.json.xml.XMLSerializer; public class JSONLibTest extends TestCase { public void testXML() { XMLSerializer xmlSerializer = new XMLSerializer(); String strXml1 = "<?xml version=\"1.0\" encoding=\"utf-8\"?><book>" + "<title>XML To JSON</title><author>json-lib</author></book>"; JSONObject jsonObject1 = (JSONObject) xmlSerializer.read(strXml1); System.out.println( jsonObject1 ); JSONObject jsonObject2 = new JSONObject( true ); String strXml2 = xmlSerializer.write( jsonObject2 ); System.out.println( strXml2 ); JSONArray jsonObject3 = JSONArray.fromObject("[1,2,3]"); String strXml3 = xmlSerializer.write( jsonObject3 ); System.out.println( strXml3 ); System.out.println( "jsonObject1(json to xml):"+ xmlSerializer.read(strXml1) ); System.out.println( "jsonObject2(json to xml):"+ xmlSerializer.read(strXml2) ); System.out.println( "jsonObject3(json to xml):"+ xmlSerializer.read(strXml3) ); } } //jsonObject1(xml to json):{"title":"XML To JSON","author":"json-lib"} //jsonObject2(xml to json):<?xml version="1.0" encoding="UTF-8"?> //<o null="true"/> //jsonObject3(xml to json):<?xml version="1.0" encoding="UTF-8"?> //<a><e type="number">1</e><e type="number">2</e><e type="number">3</e></a> //jsonObject1(json to xml):{"title":"XML To JSON","author":"json-lib"} //jsonObject2(json to xml):null //jsonObject3(json to xml):["1","2","3"]

 

그런데 위의 소스를 돌려보면 java.lang.NoClassDefFoundError: nu/xom/Element 를 던진다.

 

json-lib 사이트에서 살펴보면 이와 관련된 언급이 없는 것 같은데...

 

라이브러리를 하나 추가해야 한다.

XOM(XML Object Model) 라이브러리를 추가해야한다. 여기서 다운로드 할 수 있다.

 

 

 

 

위의 코드를 돌려보면서 발생할 수 있는 Exception은 다음과 같다.

• java.lang.NoClassDefFoundError
  • 위의 의존성 패키지에서 누락된게 있는지 확인해본다.
• org.apache.commons.lang.exception.NestableRuntimeException
  • 최신버전 (commons-lang3-3.1.jar) 사용시에 오류 발생
• java.lang.NoClassDefFoundError: nu/xom/Element
  • XML을 사용할 때 라이브러리를 추가한다.

 

 

 

 

끝.