HashMap转换成Json格式

Java代码  ：

import java.io.IOException; 
import java.util.HashMap; 
import java.util.Iterator; 
import java.util.List; 
import java.util.Map.Entry; 
 
import javax.servlet.http.HttpServletResponse; 
/**
* 把Hshmap转换成json，拼装后以html格式输出
*
*/ 
public class HashmapToJson { 
    /**把数据源HashMap转换成json
     * @param map 
     */ 
    public static String hashMapToJson(HashMap map) { 
        String string = "{"; 
        for (Iterator it = map.entrySet().iterator(); it.hasNext();) { 
            Entry e = (Entry) it.next(); 
            string += "'" + e.getKey() + "':"; 
            string += "'" + e.getValue() + "',"; 
        } 
        string = string.substring(0, string.lastIndexOf(",")); 
        string += "}"; 
        return string; 
    } 
    /**
     * 输出json到HTML
     * @param response 
     * @param jsonString 要输出的字符串
     */ 
    public void outJson(HttpServletResponse response, String jsonString) { 
        response.setContentType("text/html"); 
        response.setCharacterEncoding("utf-8"); 
        response.setHeader("Pragma", "no-cache"); 
        response.setHeader("Cache-Control", "no-cache, must-revalidate"); 
        response.setHeader("Pragma", "no-cache"); 
        try { 
            response.getWriter().println(jsonString); 
            response.getWriter().flush(); 
            response.getWriter().close(); 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } 
    } 
    /**
     * 拼装json，输出
     * @param list
     * @param response
     */ 
    public static void toJson(List list, HttpServletResponse response) { 
        HashmapToJson toJson = new HashmapToJson(); 
        String jsonString = "["; 
        for (int i = 0; i < list.size(); i++) { 
            if (i != 0) 
                jsonString += ","; 
            jsonString += toJson.hashMapToJson((HashMap) list.get(i)); 
        } 
        jsonString += "]"; 
        toJson.outJson(response, jsonString); 
    } 
}