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 程式師世界 >> 編程語言 >> JAVA編程 >> JAVA編程入門知識 >> java 和 json 對象間轉換

java 和 json 對象間轉換

編輯:JAVA編程入門知識

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

commons-lang 2.5
commons-beanutils 1.8.0
commons-collections 3.2.1
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
代碼如下:

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
        MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);
        System.out.println(diyBean);

        System.out.println("do the list release");
        List<Person> list = diyBean.getList();
        for(Person o : list){
            Person p = (Person)o;
            System.out.println(p.getName());
        }

        System.out.println("do the map release");

        //先往注冊器中注冊變換器,需要用到ezmorph包中的類
        MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();
        Morpher dynaMorpher = new BeanMorpher( Person.class,  morpherRegistry); 
        morpherRegistry.registerMorpher( dynaMorpher ); 

       
        Map map = diyBean.getMap();
        /*這裡的map沒進行類型暗示,故按默認的,裡面存的為net.sf.ezmorph.bean.MorphDynaBean類型的對象*/
        System.out.println(map);
      /*輸出:
        {testOne=net.sf.ezmorph.bean.MorphDynaBean@f73c1[
          {name=test1}
        ], testTwo=net.sf.ezmorph.bean.MorphDynaBean@186c6b2[
          {name=test2}
        ]}
      */
        List<Person> output = new ArrayList(); 
        for( Iterator i = map.values().iterator(); i.hasNext(); ){ 
            //使用注冊器對指定DynaBean進行對象變換
           output.add( (Person)morpherRegistry.morph( Person.class, i.next() ) ); 
        } 

        for(Person p : output){
            System.out.println(p.getName());
        /*輸出:
          test1
          test2
        */
        }

    }     
}

5.下面提供上面例子所需的資源,包括jar包和代碼
/Files/mailingfeng/json-lib/json-lib用例所需jar包和java類.rar

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