Json-lib使用——JSONObject与JSONArray

Json-lib使用——JSONObject与JSONArray

（1）示例一

Book book=new Book();
book.setName("Java");
book.setPrice(52.3f);
JSONObject object=JSONObject.fromObject(book);
System.out.println(object.toString());

 
（2）示例二

Book book=new Book();
book.setName("Java");
book.setPrice(52.3f);
     
Book book2=new Book();
book2.setName("C");
book2.setPrice(42.3f);
List list=new ArrayList();
list.add(book);
list.add(book2);
JSONArray arry=JSONArray.fromObject(list);
System.out.println(arry.toString());

 
//结果如下：
[{"name":"Java","price":52.3},{"name":"C","price":42.3}]

2.从String到Object
要先用String对象构造一个JSONObject或者JSONArray对象
(1)示例一

String json="{name:'Java',price:52.3}";    
JSONObject object=JSONObject.fromObject(json);
System.out.println(object.get("name")+" "+object.get("price"));

 

(2)示例二

String json="[{name:'Java',price:52.3},{name:'C',price:42.3}]";
JSONArray array=JSONArray.fromObject(json);
for(int i=0;i<array.size();i++){
Map o=(Map)array.get(i);
System.out.println(o.get("name")+" "+o.get("price"));
}

 

3.从String到Bean

(1)单个Bean对象

String json="{name:'Java',price:52.3}";
JSONObject object=JSONObject.fromObject(json);
Product product=(Product)JSONObject.toBean(object,Product.class);
System.out.println(product.getName()+" "+product.getPrice());

 
(2).Bean的数组

String json="[{name:'Java',price:52.3},{name:'C',price:42.3}]";
JSONArray array=JSONArray.fromObject(json);
Product[] products=(Product[]) JSONArray.toArray(array,Product.class);
for(Product p:products){
System.out.println(p.getName()+" "+p.getPrice());
}

 
自定义封装JSON操作的类

package com.util;

import java.util.List;
import java.util.Map;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class JsonHelper {
//从普通的Bean转换为字符串
   public static String getJson(Object o){
         JSONObject jo=JSONObject.fromObject(o);
         return jo.toString();
    }
     //从Java的列表转换为字符串
     public static String getJson(List list){
         JSONArray ja=JSONArray.fromObject(list);
         return ja.toString();
     }
     //从Java对象数组转换为字符串
     public static String getJson(Object[] arry){
         JSONArray ja=JSONArray.fromObject(arry);
         return ja.toString();
     }
     //从json格式的字符串转换为Map对象
     public static Map getObject(String s){
         return     JSONObject.fromObject(s);
     }
     //从json格式的字符串转换为List数组
     public static List getArray(String s){
         return JSONArray.fromObject(s);
     }
     //从json格式的字符串转换为某个Bean
     public static Object getObject(String s,Class cls){
         JSONObject jo=JSONObject.fromObject(s);
         return JSONObject.toBean(jo, cls);
     }
     //从json格式的字符串转换为某类对象的数组
     public static Object getArray(String s,Class cls){
         JSONArray ja=JSONArray.fromObject(s);
         return JSONArray.toArray(ja, cls);
     }
}