Java处理JSON的工具类（List、Map和JSON之间的转换)——依赖jsonlib支持Map嵌套

原文链接：http://www.itjhwd.com/java_json/

package com.itjh.mmp.util;

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.

* <br>本类为处理json的工具类

* @author slj

 */

public class JsonTools {

    /**

     *

    * json转换list.

    * <br>详细说明

    * @param jsonStr json字符串

    * @return

    * @return List<Map<String,Object>> list

    * @throws

    * @author slj

    * @date 2013年12月24日 下午1:08:03

     */

    public static List<Map<String, Object>> parseJSON2List(String jsonStr){

        JSONArray jsonArr = JSONArray.fromObject(jsonStr);

        List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();

        Iterator<JSONObject> it = jsonArr.iterator();

        while(it.hasNext()){

            JSONObject json2 = it.next();

            list.add(parseJSON2Map(json2.toString()));

        }

        return list;

    }

   /**

    *

   * json转换map.

   * <br>详细说明

   * @param jsonStr json字符串

   * @return

   * @return Map<String,Object> 集合

   * @throws

   * @author slj

    */

    public static Map<String, Object> 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<Map<String, Object>> list = new ArrayList<Map<String,Object>>();

                Iterator<JSONObject> 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.

    * <br>通过HTTP获取JSON数据返回list

    * @param url 链接

    * @return

    * @return List<Map<String,Object>> list

    * @throws

    * @author slj

     */

    public static List<Map<String, Object>> 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.

   * <br>通过HTTP获取JSON数据返回map

   * @param url 链接

   * @return

   * @return Map<String,Object> 集合

   * @throws

   * @author slj

    */

    public static Map<String, Object> 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.

    * <br>详细说明

    * @param map 集合

    * @return

    * @return String json字符串

    * @throws

    * @author slj

     */

    public static String mapToJson(Map<String, String> map) {

        Set<String> keys = map.keySet();

        String key = "";

        String value = "";

        StringBuffer jsonBuffer = new StringBuffer();

        jsonBuffer.append("{");

        for (Iterator<String> 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<Map<String,Object>> list = getListByUrl(url);

        System.out.println(list);

    }

}

经过实际测试，Map嵌套可以成功转换！