json格式数据如何显示在fusionchart中

Ext.other.statisticsissuer = Ext.extend(Ext.Panel,{
constructor: function(){
var issuerList;
Ext.Ajax.request({
url: BASE_PATH + '/other/StatIssuer.action',
method: "GET",
async: false,
success: function(response, options){
issuerList =  response.responseText ;
alert(response.responseText);
},
scope: this
});

Ext.other.statisticsissuer.superclass.constructor.call(this,{
frame: false,
border: false,
bodyStyle: "padding:0 0", 
layout: 'form',
autoScroll: true,
items: [
new Ext.FormPanel({
  layout:'fit',
  height:1000,
  width:1000
  })
],
mmmm:function()
{
changeData.params({
changeType:'single',
objectData: jsonObject,
caption:"水果月销量报表",
xAxisName:"月份",
yAxisName:"销量",
seriesname:"key3",
categoryName:"key1",
showValues:"0",
render:"single_fcf_div",
chartType:"Pie3D.swf"
});
changeData.render(this.get(0).id);

}
  });

}
});issuerList 是从java后台返回的json格式的数据，如何显示出来呢？ 这个前台我是已经用了ext的 想要在ext页面把这个饼图显示出来