Java List或Map对象和json字符串数据的相互转化

Java代码JsonKit类

package cn.okek.util;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * 实用工具包
 * @author 周文鹏
 * @date 2014-1-21
 */
public class JsonKit {
	
	/**
	 * 将list转为json
	 * @param lists
	 * @param sb
	 * @return
	 */
	public static StringBuilder listToJson(List lists, StringBuilder sb) {
		if (sb == null) sb = new StringBuilder();
		sb.append("[");
		for (int i = 0; i < lists.size(); i++) {
			Object o = lists.get(i);
			if (o instanceof Map) {
				Map map = (Map) o;
				mapToJson(map, sb);
			} else if (o instanceof List) {
				List l = (List) o;
				listToJson(l, sb);
			} else {
				sb.append("\"" + o + "\"");
			}
			if (i != lists.size() - 1) sb.append(",");
		}
		sb.append("]");
		return sb;
	}
	
	/**
	 * 将map转为json
	 * @param map
	 * @param sb
	 * @return
	 */
	public static StringBuilder mapToJson(Map map, StringBuilder sb) {
		if (sb == null) sb = new StringBuilder();
		sb.append("{");
		Iterator iter = map.entrySet().iterator();
		while (iter.hasNext()) { 
			Entry entry = (Entry) iter.next();
		    String key = entry.getKey() != null ? entry.getKey().toString() : "";
		    sb.append("\"" + stringToJson(key) + "\":");
		    Object o = entry.getValue();
		    if (o instanceof List) {
				List l = (List) o;
				listToJson(l, sb);
			} else if (o instanceof Map) {
				Map m = (Map) o;
				mapToJson(m, sb);
			} else {
				String val = entry.getValue() != null ? entry.getValue().toString() : "";
				sb.append("\"" + stringToJson(val) + "\"");
			}
		    if (iter.hasNext()) sb.append(",");
		}
		sb.append("}");
		return sb;
	}
	
	/**
	 * 将字符串转为json数据
	 * @param str 数据字符串
	 * @return json字符串
	 */
	private static String stringToJson(String str) {  
        StringBuffer sb = new StringBuffer();  
        for (int i = 0; i < str.length(); i++) {  
            char c = str.charAt(i);  
            switch (c) {  
                case '\"':  
                    sb.append("\\\"");  
                    break;  
                case '\\':  
                    sb.append("\\\\");  
                    break;  
                case '/':  
                    sb.append("\\/");  
                    break;  
                case '\b':  
                    sb.append("\\b");  
                    break;  
                case '\f':  
                    sb.append("\\f");  
                    break;  
                case '\n':  
                    sb.append("\\n");  
                    break;  
                case '\r':  
                    sb.append("\\r");  
                    break;  
                case '\t':  
                    sb.append("\\t");  
                    break;  
                default:  
                    sb.append(c);  
            }  
        }  
        return sb.toString();  
    }
	
	/**
	 * JsonArray转List
	 * @param jsonArr
	 * @return
	 * @throws JSONException
	 */
	public static List