如何使用json-lib實現Java和JSON之間的轉換

1. json-lib是一個java類庫，提供將Java對象，包括beans, maps, collections, java arrays and XML等轉換成JSON，或者反向轉換的功能。

2. json-lib 主頁 ： http://json-lib.sourceforge.net/

3.執行環境

需要以下類庫支持

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

4.功能示例

這裡通過JUnit-Case例子給出代碼示例

package com.mai.json;  
      
import static org.junit.Assert.assertEquals;  
      
import java.util.ArrayList;  
import java.util.Date;  
import java.util.HashMap;  
import java.util.Iterator;  
import java.util.List;  
import java.util.Map;  
import net.sf.ezmorph.Morpher;  
import net.sf.ezmorph.MorpherRegistry;  
import net.sf.ezmorph.bean.BeanMorpher;  
import net.sf.json.JSONArray;  
import net.sf.json.JSONObject;  
import net.sf.json.util.JSONUtils;  
      
import org.apache.commons.beanutils.PropertyUtils;  
import org.junit.Test;  
      
public class JsonLibTest {  
      
    /* 
     *  普通類型、List、Collection等都是用JSONArray解析 
     *   
     *  Map、自定義類型是用JSONObject解析 
     *  可以將Map理解成一個對象，裡面的key/value對可以理解成對象的屬性/屬性值 
     *  即{key1:value1,key2,value2......} 
     *  
     * 1.JSONObject是一個name:values集合，通過它的get(key)方法取得的是key後對應的value部分(字符串) 
     *         通過它的getJSONObject(key)可以取到一個JSONObject，--> 轉換成map, 
     *         通過它的getJSONArray(key) 可以取到一個JSONArray ， 
     *  
     *  
     */  
          
    //一般數組轉換成JSON  
    @Test  
    public void testArrayToJSON(){  
        boolean[] boolArray = new boolean[]{true,false,true};    
        JSONArray jsonArray = JSONArray.fromObject( boolArray );    
        System.out.println( jsonArray );    
        // prints [true,false,true]    
    }  
          
          
    //Collection對象轉換成JSON  
    @Test  
    public void testListToJSON(){  
        List list = new ArrayList();    
        list.add( "first" );    
        list.add( "second" );    
        JSONArray jsonArray = JSONArray.fromObject( list );    
        System.out.println( jsonArray );    
        // prints ["first","second"]    
    }  
          
          
    //字符串json轉換成json， 根據情況是用JSONArray或JSONObject  
    @Test  
    public void testJsonStrToJSON(){  
        JSONArray jsonArray = JSONArray.fromObject( "['json','is','easy']" );    
        System.out.println( jsonArray );    
        // prints ["json","is","easy"]    
    }  
          
          
    //Map轉換成json， 是用jsonObject  
    @Test  
    public void testMapToJSON(){  
        Map map = new HashMap();    
        map.put( "name", "json" );    
        map.put( "bool", Boolean.TRUE );    
        map.put( "int", new Integer(1) );    
        map.put( "arr", new String[]{"a","b"} );    
        map.put( "func", "function(i){ return this.arr[i]; }" );    
                
        JSONObject jsonObject = JSONObject.fromObject( map );    
        System.out.println( jsonObject );    
    }  
          
    //復合類型bean轉成成json  
    @Test  
    public void testBeadToJSON(){  
        MyBean bean = new MyBean();  
        bean.setId("001");  
        bean.setName("銀行卡");  
        bean.setDate(new Date());  
              
        List cardNum = new ArrayList();  
        cardNum.add("農行");  
        cardNum.add("工行");  
        cardNum.add("建行");  
        cardNum.add(new Person("test"));  
              
        bean.setCardNum(cardNum);  
              
        JSONObject jsonObject = JSONObject.fromObject(bean);  
        System.out.println(jsonObject);  
              
    }  
          
    //普通類型的json轉換成對象  
    @Test  
    public void testJSONToObject() throws Exception{  
        String json = "{name=\"json\",bool:true,int:1,double:2.2,func:function(a){ return a; },array:[1,2]}";    
        JSONObject jsonObject = JSONObject.fromObject( json );   
        System.out.println(jsonObject);  
        Object bean = JSONObject.toBean( jsonObject );   
        assertEquals( jsonObject.get( "name" ), PropertyUtils.getProperty( bean, "name" ) );    
        assertEquals( jsonObject.get( "bool" ), PropertyUtils.getProperty( bean, "bool" ) );    
        assertEquals( jsonObject.get( "int" ), PropertyUtils.getProperty( bean, "int" ) );    
        assertEquals( jsonObject.get( "double" ), PropertyUtils.getProperty( bean, "double" ) );    
        assertEquals( jsonObject.get( "func" ), PropertyUtils.getProperty( bean, "func" ) );    
        System.out.println(PropertyUtils.getProperty(bean, "name"));  
        System.out.println(PropertyUtils.getProperty(bean, "bool"));  
        System.out.println(PropertyUtils.getProperty(bean, "int"));  
        System.out.println(PropertyUtils.getProperty(bean, "double"));  
        System.out.println(PropertyUtils.getProperty(bean, "func"));  
        System.out.println(PropertyUtils.getProperty(bean, "array"));  
              
        List arrayList = (List)JSONArray.toCollection(jsonObject.getJSONArray("array"));  
        for(Object object : arrayList){  
            System.out.println(object);  
        }  
              
    }  
          
          
    //將json解析成復合類型對象, 包含List  
    @Test  
    public void testJSONToBeanHavaList(){  
        String json = "{list:[{name:'test1'},{name:'test2'}],map:{test1:{name:'test1'},test2:{name:'test2'}}}";  
//        String json = "{list:[{name:'test1'},{name:'test2'}]}";  
        Map classMap = new HashMap();  
        classMap.put("list", Person.class);  
        MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);  
        System.out.println(diyBean);  
              
        List list = diyBean.getList();  
        for(Object o : list){  
            if(o instanceof Person){  
                Person p = (Person)o;  
                System.out.println(p.getName());  
            }  
        }  
    }  
          
          
    //將json解析成復合類型對象, 包含Map  
    @Test  
    public void testJSONToBeanHavaMap(){  
        //把Map看成一個對象  
        String json = "{list:[{name:'test1'},{name:'test2'}],map:{testOne:{name:'test1'},testTwo:{name:'test2'}}}";  
        Map classMap = new HashMap();  
        classMap.put("list", Person.class);  
        classMap.put("map", Map.class);  
        //使用暗示，直接將json解析為指定自定義對象，其中List完全解析,Map沒有完全解析
		// 查看本欄目
/Files/mailingfeng/json-lib/json-lib用例所需jar包和java類.rar
http://download.csdn.net/detail/shimiso/7058455