java处理json的工具类(list,map和json的之间的转换)

需要下载第三方的jar ：net.sf.json

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections.map.ListOrderedMap;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
/**
 * 
* 处理json的工具类.
* 
本类为处理json的工具类
* @author slj
 */
public class JsonTools {

    /**
     * 
    * json转换list.
    * 
详细说明
    * @param jsonStr json字符串
    * @return
    * @return List> list
    * @throws
    * @author slj
    * @date 2013年12月24日 下午1:08:03
     */
    public static List> parseJSON2List(String jsonStr){
        JSONArray jsonArr = JSONArray.fromObject(jsonStr);
        List> list = new ArrayList>();
        Iterator it = jsonArr.iterator();
        while(it.hasNext()){
            JSONObject json2 = it.next();
            list.add(parseJSON2Map(json2.toString()));
        }
        return list;
    }

   /**
    * 
   * json转换map.
   * 
详细说明
   * @param jsonStr json字符串
   * @return
   * @return Map 集合
   * @throws
   * @author slj
    */
    public static Map parseJSON2Map(String jsonStr){
        ListOrderedMap map = new ListOrderedMap();
        //最外层解析
        JSONObject json = JSONObject.fromObject(jsonStr);
        for(Object k : json.keySet()){
            Object v = json.get(k); 
            //如果内层还是数组的话，继续解析
            if(v instanceof JSONArray){
                List> list = new ArrayList>();
                Iterator it = ((JSONArray)v).iterator();
                while(it.hasNext()){
                    JSONObject json2 = it.next();
                    list.add(parseJSON2Map(json2.toString()));
                }
                map.put(k.toString(), list);
            } else {
                map.put(k.toString(), v);
            }
        }
        return map;
    }

    /**
     * 
    * 通过HTTP获取JSON数据.
    * 
通过HTTP获取JSON数据返回list
    * @param url 链接
    * @return
    * @return List> list
    * @throws
    * @author slj
     */
    public static List> getListByUrl(String url){
        try {
            //通过HTTP获取JSON数据
            InputStream in = new URL(url).openStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            StringBuilder sb = new StringBuilder();
            String line;
            while((line=reader.readLine())!=null){
                sb.append(line);
            }
            return parseJSON2List(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

   /**
    * 
   * 通过HTTP获取JSON数据.
   * 
通过HTTP获取JSON数据返回map
   * @param url 链接
   * @return
   * @return Map 集合
   * @throws
   * @author slj
    */
    public static Map getMapByUrl(String url){
        try {
            //通过HTTP获取JSON数据
            InputStream in = new URL(url).openStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            StringBuilder sb = new StringBuilder();
            String line;
            while((line=reader.readLine())!=null){
                sb.append(line);
            }
            return parseJSON2Map(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    /**
     * 
    * map转换json.
    * 
详细说明
    * @param map 集合
    * @return
    * @return String json字符串
    * @throws
    * @author slj
     */
    public static String mapToJson(Map map) {
        Set keys = map.keySet();
        String key = "";
        String value = "";
        StringBuffer jsonBuffer = new StringBuffer();
        jsonBuffer.append("{");
        for (Iterator it = keys.iterator(); it.hasNext();) {
            key = (String) it.next();
            value = map.get(key);
            jsonBuffer.append(key + ":" +"\""+ value+"\"");
            if (it.hasNext()) {
                jsonBuffer.append(",");
            }
        }
        jsonBuffer.append("}");
        return jsonBuffer.toString();
    }

    //test
    public static void main(String[] args) {
        String url = "http://...";
        List> list = getListByUrl(url);
        System.out.println(list);
    }
}