（Java 基础知识） json_lib实现java 对象转化为json对象

桃扇骨 2023-10-16 20:21 38阅读 0赞

JSON\_lib简介：

json-lib是一个java类库，提供将Java对象，包括beans, maps, collections, java arrays and XML等转换成JSON，或者反向转换的功能。

JSON\_lib主页：

[http://json-lib.sourceforge.net/][http_json-lib.sourceforge.net]

JSON\_lib开发环境搭建：

需要以下类库支持

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

资源下载路径：

JSON\_lib功能示例

这里通过JUnit-Case例子给出代码示例

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 {
    
        /*
         *  普通类型、List、Collection等都是用JSONArray解析
         *  
         *  Map、自定义类型是用JSONObject解析
         *  可以将Map理解成一个对象，里面的key/value对可以理解成对象的属性/属性值
         *  即{key1:value1,key2,value2......}
         * 
         * 1.JSONObject是一个name:values集合，通过它的get(key)方法取得的是key后对应的value部分(字符串)
         *         通过它的getJSONObject(key)可以取到一个JSONObject，--> 转换成map,
         *         通过它的getJSONArray(key) 可以取到一个JSONArray ，
         * 
         * 
         */
        
        //一般数组转换成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对象转换成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转换成json， 根据情况是用JSONArray或JSONObject
        @Test
        public void testJsonStrToJSON(){
            JSONArray jsonArray = JSONArray.fromObject( "['json','is','easy']" );  
            System.out.println( jsonArray );  
            // prints ["json","is","easy"]  
        }
        
        
        //Map转换成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 );  
        }
        
        //复合类型bean转成成json
        @Test
        public void testBeadToJSON(){
            MyBean bean = new MyBean();
            bean.setId("001");
            bean.setName("银行卡");
            bean.setDate(new Date());
            
            List cardNum = new ArrayList();
            cardNum.add("农行");
            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);
            
        }
        
        //普通类型的json转换成对象
        @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);
            }
            
        }
        
        
        //将json解析成复合类型对象, 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());
                }
            }
        }
        
        
        //将json解析成复合类型对象, 包含Map
        @Test
        public void testJSONToBeanHavaMap(){
            //把Map看成一个对象
            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，直接将json解析为指定自定义对象，其中List完全解析,Map没有完全解析
            MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);
            System.out.println(diyBean);
            
            System.out.println("do the list release");
            List list = diyBean.getList();
            for(Person o : list){
                Person p = (Person)o;
                System.out.println(p.getName());
            }
            
            System.out.println("do the map release");
            
            //先往注册器中注册变换器，需要用到ezmorph包中的类
            MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();
            Morpher dynaMorpher = new BeanMorpher( Person.class,  morpherRegistry);  
            morpherRegistry.registerMorpher( dynaMorpher );  
            
            
            Map map = diyBean.getMap();
            /*这里的map没进行类型暗示，故按默认的，里面存的为net.sf.ezmorph.bean.MorphDynaBean类型的对象*/
            System.out.println(map);
    /*输出:
    {testOne=net.sf.ezmorph.bean.MorphDynaBean@f73c1[
      {name=test1}
    ], testTwo=net.sf.ezmorph.bean.MorphDynaBean@186c6b2[
      {name=test2}
    ]}
    */
            List output = new ArrayList();  
            for( Iterator i = map.values().iterator(); i.hasNext(); ){  
                //使用注册器对指定DynaBean进行对象变换
               output.add( (Person)morpherRegistry.morph( Person.class, i.next() ) );  
            }  
            
            for(Person p : output){
                System.out.println(p.getName());
    /*输出:
    test1
    test2
    */
            }
            
        }
        
        
        
    }

[http_json-lib.sourceforge.net]: http://json-lib.sourceforge.net/