json数据处理

json数据处理

一、JAR包简介
      要使程序可以运行必须引入JSON-lib包，JSON-lib包同时依赖于以下的JAR包：
      1.commons-lang.jar
      2.commons-beanutils.jar
      3.commons-collections.jar
      4.commons-logging.jar
      5.ezmorph.jar
      6.json-lib-2.2.2-jdk15.jar

二、后台处理
 
    1.JSONObject用于处理单个对象

        User user  =   new  User( " zhangsan " , 200 );
        JSONObject json  =  JSONObject.fromObject(user);
        System.out.println( " ========== " + json + " ========== " );
        PrintWriter out  =  response.getWriter();
        out.print(json);
        out.flush();
        out.close();

      返回的结果：=========={"name":"zhangsan","money":200}==========

   2.JSONArray用于处理集合例如list

        User user1  =   new  User( " zhangsan " , 200 );
        User user2  =   new  User( " lisi " , 400 );
        List < User >  userList  =   new  ArrayList < User > ();
        userList.add(user1);
        userList.add(user2);
        JSONArray jsonArray  =  JSONArray.fromObject(userList);
        System.out.println( " ==========jsonArray:   " + jsonArray + "   ========== " );
        PrintWriter out  =  response.getWriter();
        out.print(jsonArray);
        out.flush();
        out.close();

   返回的结果：==========jsonArray:  [{"name":"zhangsan","money":200},{"name":"lisi","money":400}]  ==========

三、前台js处理
 
   1.JSONObject返回的单个对象

       $(document).ready( function (){
            var  url  =   " <%=basePath%>servlet/jsonServlet " ;
           $.get(url,{
           }, function (data){
                 $('#onLine_count').text(data.money);              
           }, " json " );
       });

   2.JSONArray返回的数组

    $.getJSON(url,{ " parentGroupId " :parentGroupId},  function (json){
        $('#first_sort_org').empty();
         for ( var  i = 0 ;i < json.length;i ++ ) {
             var  code  =  json[i].id;
             var  name  =  json[i].name;
             if (type == " groupUser " ) {
                name  =  json[i].showName;
            }
             var  childSelectId  =  'first_sort_org';
            $( " <option></option> " ).val(code).text(i + 1 + " .  " + name).appendTo($('#first_sort_org'));
        }
    });

  


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