一.json常用转换方法

1.list

List list = new ArrayList();
list.add("first");
list.add("second");
JSONArray jsonArray2 = JSONArray.fromObject(list);

2.map

Map map = new HashMap();
map.put("name", "json");
map.put("bool", Boolean.TRUE);
map.put("int", new Integer(1));
map.put("arr", new String[] { "a", "b" });
map.put("func", "function(i){ return this.arr[i]; }");
JSONObject json = JSONObject.fromObject(map);

3.bean

JSONObject jsonObject = JSONObject.fromObject(new JsonBean());

4.数组

boolean[] boolArray = new boolean[] { true, false, true }; 
JSONArray jsonArray1 = JSONArray.fromObject(boolArray);

5.一般数据

JSONArray jsonArray3 = JSONArray.fromObject("['json','is','easy']" );

6.beans

List list = new ArrayList();
JsonBean2 jb1 = new JsonBean2();
jb1.setCol(1);
jb1.setRow(1);
jb1.setValue("xx");
JsonBean2 jb2 = new JsonBean2();
jb2.setCol(2);
jb2.setRow(2);
jb2.setValue("");
list.add(jb1);
list.add(jb2);
JSONArray ja = JSONArray.fromObject(list);

二.HTML页面将String转换成json

eval()

function testFunction() {
	var jsonStr = '${str}';
	var dataObj = eval("(" + jsonStr + ")");//转换为json对象
	$.each(dataObj.info, function(idx, item) {
		alert("name:" + item.uuid + " , vaddress:" + item.vaddress);
	});
}

三.后台向前台传json

1.使用转义符  \

2.交给前台来处理 eval()

3.使用json工具类

后台代码:

        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//1.返回标准的json字符串(双引号要用转义符)
		//String s = "[{\"id\":1,\"text\":\"Root node\",\"children\":[{\"id\":2,\"text\":\"Child node 1\",\"children\":true},{\"id\":3,\"text\":\"Child node 2\"}]}]";
		
		//2.前台使用eval()函数将string装换成json格式
		//String s = "[{id:1,text:'Root node',children:[{id:2,text:'Child node 1',children:true},{id:3,text:'Child node 2'}]}]";
		
		//3.使用json工具类
		JSONArray s = getJson();
		response.setContentType("json");
		
		response.getWriter().print(s);
	}

        private JSONArray getJson() {
		JSONObject jo1 = new JSONObject();
		JSONObject jo2 = new JSONObject();
		jo1.put("id", 2);
		jo1.put("text", "Child node 1");
		jo2.put("id", 3);
		jo2.put("text", "Child node 2");
		JSONArray jsonArray = new JSONArray();
		jsonArray.add(jo1);
		jsonArray.add(jo2);
		JSONObject jsonObject = new JSONObject();
		jsonObject.put("id", 1);
		jsonObject.put("text", "Root node");
		jsonObject.put("children", jsonArray);
		JSONArray json = new JSONArray();
		json.add(jsonObject);
		return json;
	}

前台代码:

<div id="jstree"></div>
	<script>
		$(function() {
			$.ajax({
				url : "IndexServlet",
				datatype : "json",
				success : function(o) {
					create(o);
				}
			});
		});
		function create(data) {
			//data = eval("(" + data + ")");
			$('#jstree').jstree({
				"core" : {
					"data" : data
				},
			});
		}
		/* $(function() {
			$('#jstree').jstree({
				'core' : {
					'data' : {
						"url" : "IndexServlet",
						"data" : function(node) {
							return {
								"id" : node.id
							};
						},
					    "dataFilter" : function(o) {
							o = eval("(" + o + ")");
							console.info(o);
							return o;
						} 
					}
				}
			});
		}); */
	</script>