JSON工具类

JSON工具类

package com.fh.util;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
/**
 * 
 * @author donald
 *
 */
public class JsonUtil {
	 /** 
     * 对象转换成JSON字符串  obj
     * @param obj 需要转换的对象 
     * @return 对象的string字符 
     */  
    public static String toJson(Object obj) {  
        JSONObject jSONObject = JSONObject.fromObject(obj);  
        return jSONObject.toString();  
    }  
  /**
     * just for String[]
     * @param obj
     * @return
     */
    public static String ArraytoJson(Object obj) {  
    	JSONArray jsonArr = JSONArray.fromObject(obj);  
        return jsonArr.toString();  
    }  
    /** 
     * JSON字符串转换成对象 
     * @param jsonString  需要转换的字符串 
     * @param type 需要转换的对象类型 
     * @return 对象 
     */  
    @SuppressWarnings("unchecked")  
    public static <T> T fromJson(String jsonString, Class<T> type) {  
        JSONObject jsonObject = JSONObject.fromObject(jsonString);  
        return (T) JSONObject.toBean(jsonObject, type);  
    }  
    public static <T> String ListToJson(List<T> lobj){
    	JSONArray jsonArr = JSONArray.fromObject(lobj);
    	return jsonArr.toString();
    }
    /**
     * 根据json String 返回List
     * @param json
     * @return
     */
    public static List<Object> jsonToList(String json){
    	JSONArray jsonArr = JSONArray.fromObject(json);
    	return jsonToList(jsonArr);
    }
    /**
     * 将Json String转化为 bean list
     * @param jsonArray
     * @param clazz
     * @return
     */
    @SuppressWarnings({ "rawtypes" })
	public static List jsonToList(String json,Class clazz){
    	JSONArray jsonArr = JSONArray.fromObject(json);
    	return jsonToList(jsonArr,clazz);
    }
    /**
     * 将JSONArray转化为 bean list
     * @param jsonArray
     * @param clazz
     * @return
     */
    @SuppressWarnings({ "rawtypes", "deprecation" })
	public static List jsonToList( JSONArray jsonArray,Class clazz){
        if(jsonArray!=null){
            try{
                List  list =  JSONArray.toList(jsonArray,clazz);
                return list;
            }catch(Exception e){
                return null;
            }
        }else{
            return null;
        }
    }
    /** 
     * 将JSONArray对象转换成list集合 map 
     * @param jsonArr 
     * @return 
     */  
    public static List<Object> jsonToList(JSONArray jsonArr) {  
        List<Object> list = new ArrayList<Object>();  
        for (Object obj : jsonArr) {  
            if (obj instanceof JSONArray) {  
                list.add(jsonToList((JSONArray) obj));  
            } else if (obj instanceof JSONObject) {  
                list.add(jsonToMap((JSONObject) obj));  
            } else {  
                list.add(obj);  
            }  
        }  
        return list;  
    }  
  
    /** 
     * 将json字符串转换成map对象 
     *  
     * @param json 
     * @return 
     */  
    public static Map<String, Object> jsonToMap(String json) {  
        JSONObject obj = JSONObject.fromObject(json);  
        return jsonToMap(obj);  
    }  
  
    /** 
     * 将JSONObject转换成map对象 
     *  
     * @param json 
     * @return 
     */  
    public static Map<String, Object> jsonToMap(JSONObject obj) {  
        Set<?> set = obj.keySet();  
        Map<String, Object> map = new HashMap<String, Object>(set.size());  
        for (Object key : obj.keySet()) {  
            Object value = obj.get(key);  
            if (value instanceof JSONArray) {  
                map.put(key.toString(), jsonToList((JSONArray) value));  
            } else if (value instanceof JSONObject) {  
                map.put(key.toString(), jsonToMap((JSONObject) value));  
            } else {  
                map.put(key.toString(), obj.get(key));  
            }  
  
        }  
        return map;  
    }  
}

测试类

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import entity.Cat;

import util.JsonUtil;


public class testJson {
	public static void main(String[] args){
		Map<String ,String > bmap = new HashMap<String,String>();
		bmap.put("user", "donald");
		bmap.put("age", "32");
		String bString = JsonUtil.toJson(bmap);
		System.out.println("============map:"+bString);
		Map<String, Object> bmaps = JsonUtil.jsonToMap(bString);
		System.out.println("============user:"+bmaps.get("user"));
		System.out.println("============age:"+bmaps.get("age"));
		Cat cat1 = new Cat(4,"mini");
		String cString = JsonUtil.toJson(cat1);
		System.out.println("============Cat:"+cString);
		Cat cat2 = JsonUtil.fromJson(cString, Cat.class);
		System.out.println("============legs:"+cat2.getLegs());
		System.out.println("============name:"+cat2.getName());
		cat2.setLegs(5);
		cat2.setName("big");
		List<Cat> catList = new ArrayList<Cat>();
		catList.add(cat1);
		catList.add(cat2);
		String clString = JsonUtil.ListToJson(catList);
		System.out.println("============CatList:"+clString);
		List<Cat> catListx= JsonUtil.jsonToList(clString,Cat.class);
		Cat cat3 = catListx.get(0);
		System.out.println("============legs:"+cat3.getLegs());
		System.out.println("============name:"+cat3.getName());
		
	}
}

结果输出：
============map:{"age":"32","user":"donald"}
============user:donald
============age:32
============Cat:{"legs":4,"name":"mini"}
============legs:4
============name:mini
============CatList:[{"legs":4,"name":"mini"},{"legs":5,"name":"big"}]
============legs:4
============name:mini