JSON处理工具类

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import org.apache.commons.collections.map.ListOrderedMap;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.*;

/**
 * 处理json的工具类.
 */
public class JsonUtil {
    /**
     * json转换list.
     * 
详细说明
     *
     * @param jsonStr json字符串
     * @return List> list
     * @throws
     */
    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 Map 集合
     * @throws
     */
    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 List> list
     * @throws
     */
    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 Map 集合
     * @throws
     */
    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 String json字符串
     * @throws
     */
    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();
    }
}