json字符串怎转换成json对象？

例如：有这样的字符串[{"CityId":18,"CityName":"西安","ProvinceId":27,"CityOrder":1},{"CityId":53,"CityName":"广州","ProvinceId":27,"CityOrder":1}]，用js转换成json对象

 

 

 

var data;
var json='[{"CityId":18,"CityName":"西安","ProvinceId":27,"CityOrder":1},{"CityId":53,"CityName":"广州","ProvinceId":27,"CityOrder":1}]';
eval("data="+json);
alert(data);

 

@RequestMapping(value = "/mobile", method = RequestMethod.GET)
	public @ResponseBody Map<String, String> categor() {
		Map<String, String> data = new HashMap<String, String>();
		List<ProductCategory> list = productCategoryService.findRoots();
		JsonConfig jsonConfig = new JsonConfig();
		jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);
		jsonConfig.setExcludes(new String[]{//只要设置这个数组，指定过滤哪些字段。
		          "children",    
		          "products",    
		          "brands",    
		          "parameterGroups",
		          "promotions", 
		          "attributes"    
		        });    
		JSONArray jsonObjectFromMap = JSONArray.fromObject(list,jsonConfig);
		data.put("rootProductCategories", jsonObjectFromMap.toString());
		return data;
	}

 

 

//获取分类
	function seleteceCategory(){
		$.ajax( {
			type : "GET",
			url : "product_category/mobile.jhtml",
			async:false,
			dataType:"json",
			data : {
				"id":window.id
			},
			success : function(data) {
				var dd = eval("("+data.rootProductCategories+")");
				creatNoticeFunc(dd);
			}
		});
	}
	
	function creatNoticeFunc(data){
		//data = [ "aaa", "bbb", "ccc" ]; 
		alert(data);
		alert(data.length);
		var html = "";
		for (var i = 0; i < data.length; i++) {
			alert(data[i].name);
		}
		/*html = '<label class="seleteceCategory">全部分类</label>'
		$.each(data,function(i,item){
			alert(item);
			html = html + ' | '+item.name+' | ';
		});
		html = html + '<img src="img/moreArrow.png" />';
		$("#categoryDiv").append(html);*/
	}