Json 的介绍：
JSON 可以将 JavaScript 对象中表示的一组数据转换为字符串，然后就可以在函数之间轻松地传递这个字符串，或者在异步应用程序中将字符串从 Web 客户机传递给服务器端程序。
按照最简单的形式，可以用下面这样的 JSON 表示名称/值对：
{ "firstName": "Brett" }
这样的键/值对也可以是多个：
{"name":"aaa","sex":"男","age":"20"}
从语法方面来看，这与名称/值对相比并没有很大的优势，但是在这种情况下 JSON 更容易使用，而且可读性更好。
值的数组
当需要表示一组值时，JSON 不但能够提高可读性，而且可以减少复杂性。
如果使用 JSON，就只需将多个带花括号的记录分组在一起：
{ "people": [
{ "firstName": "Brett","lastName":"McLaughlin","email": "222221" },
{ "firstName": "Jason","lastName":"Hunter","email": "22222" },
{ "firstName": "Elliotte","lastName":"Harold","email": "33333" }
]}
可以使用相同的语法表示多个值（每个值包含多个记录）：
{ "programmers": [
{ "firstName": "Brett","email": "3333" },"email": "1222" },"email": "3333" }
],
"authors": [
{ "firstName": "Isaac","lastName": "Asimov","genre": "science fiction" },
{ "firstName": "Tad","lastName": "Williams","genre": "fantasy" },
{ "firstName": "Frank","lastName": "Peretti","genre": "christian fiction" }
],
"musicians": [
{ "firstName": "Eric","lastName": "Clapton","instrument": "guitar" },
{ "firstName": "Sergei","lastName": "Rachmaninoff","instrument": "piano" }
]
}
Json也可以这样写：
{ "listaccountsresponse" : { "count":1,"account" : [ {"id":5,"name":"xian1","accounttype":0,"domainid":2,"domain":"Server","receivedbytes":649444,"sentbytes":175467975,"vmlimit":"20","vmtotal":2,"vmavailable":"18","iplimit":"20","iptotal":1,"ipavailable":"19","volumelimit":"20","volumetotal":2,"volumeavailable":0,"templateavailable":"20","vmstopped":0,"vmrunning":2,"state":"enabled","user":[{"id":5,"username":"xian1","firstname":"Eric","lastname":"Tang","email":"Wang-Ngai.Tang@pccw.com","created":"2012-03-22T09:36:44+0800","account":"xian1","domainid":2,"timezone":"Asia/Shanghai"}]} ] } }
ajax对Json格式数据的解析：
1.对简单json格式的解析：
{ "firstName": "Brett" }
写道
$.ajax({
url:"这里是你要请求的地址",
data:{"id":id},//以键/值对的形式
async : false,
dataType : "json",
success : function(data) {
alert("firstName = " + data.firstName);
}
});
注：这里的data是你从后台穿过来的Json字符传串。
后台写法：
- response.setCharacterEncoding("utf-8");
- response.setContentType("text/json;charset=UTF-8");
- PrintWriterout=null;
- Stringcount="<spanstyle="color:#000000;">{"firstName":"Brett"}</span>
-
- ;
- try{
- out=response.getWriter();
- }catch(Exceptione){
- e.printStackTrace();
- }
- out.print(count);
- out.flush();
这样就能在前台页面弹出提示框：firstName = Brett。
2.多个键/值对和上面的情况一样
3.解析Json如下数组：
{
{ "firstName": "Brett","email": "33333" }
}
$.ajax({
- url:"这里是你要请求的地址",
- data:{"id":id},
- async:false,250); line-height:18px"> dataType:"json",250); line-height:18px"> success:function(data){
- for(inti=0;i<data.length;i++){
- vardatas=data[i];
- alert(datas.firstName);
- alert(datas.lastName);
- alert(datas.email);
- });
4.解析如下Json数据
{ "programmers": [
{ "firstName": "Brett","instrument": "piano" }
]
}
varpro=data.programmers;
inti=0;i<pro.length;i++){datas=pro[i];
alert(pro.firstName);
alert(pro.lastName);
alert(pro.email);
varaut=data.authors;
inti=0;i<aut.length;i++){datas=aut[i];
alert(aut.firstName);
alert(aut.lastName);
alert(aut.genre);
varmus=data.musicians;i=0;i<mus.length;i++){datas=mus[i];
alert(mus.firstName);
alert(mus.lastName);
alert(mus.instrument);
});
5.
:"Asia/Shanghai"}]} ] } }
varaccounts=data.listaccountsresponse.account;
inti=0;i<accounts.length;i++){datas=accounts[i];
alert(datas.id);
alert(datas.name);
alert(datas.accounttype);
..........
});
-----这里是自己写的一个后台传值----------------------------------------------------------------------------------------------------------
@RequestMapping(value="/applyVm/listApplyVmCount",method={RequestMethod.GET,RequestMethod.POST})
publicvoidlistApplyVmCount(HttpServletRequestrequest,HttpServletResponseresponse){
Stringcount="";
Map<String,Integer>map=applyVmService.findApplyVmCount();
Gsongson=newGson();
count=gson.toJson(map);
out.flush();
}
