ajax 对 Json 格式的解析(转)

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": "111111" },
{ "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":"18","snapshotlimit":"20","snapshottotal":0,"snapshotavailable":"20","templatelimit":"20","templatetotal":0,"templateavailable":"20","vmstopped":0,"vmrunning":2,"state":"enabled","user":[{"id":5,"username":"xian1","firstname":"Eric","lastname":"Tang","email":"[e-mail]","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：

Java代码

1. response.setCharacterEncoding("utf-8");
2. response.setContentType("text/json;charset=UTF-8");
3. PrintWriterout=null;
4. Stringcount="<spanstyle="color:#000000;">{"firstName":"Brett"}</span>
6. ;
7. try{
8. out=response.getWriter();
9. }catch(Exceptione){
10. e.printstacktrace();
11. }
12. out.print(count);
13. 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" }
}

Js代码

1. $.ajax({
2. url:"这里是你要请求的地址",
3. data:{"id":id},//以键/值对的形式
4. async:false,
5. dataType:"json",
6. success:function(data){
7. for(inti=0;i<data.length;i++){//循环后台传过来的Json数组
8. vardatas=data[i];
9. alert(datas.firstName);
10. alert(datas.lastName);
11. alert(datas.email);
12. }
13. }
14. });

4.解析如下Json数据

{ "programmers": [
{ "firstName": "Brett","instrument": "piano" }
]
}

Highlighter" style="font-family: Monaco,

success:function(data){

varpro=data.programmers;//pro为programmers的一个数组

for(inti=0;i<pro.length;i++){//循环后台传过来的Json数组

vardatas=pro[i];

alert(pro.firstName);

alert(pro.lastName);

alert(pro.email);

}

varaut=data.authors;//aut为authors的一个数组

for(inti=0;i<aut.length;i++){//循环后台传过来的Json数组

vardatas=aut[i];

alert(aut.firstName);

alert(aut.lastName);

alert(aut.genre);

}

varmus=data.musicians;//aut为authors的一个数组

for(inti=0;i<mus.length;i++){//循环后台传过来的Json数组

vardatas=mus[i];

alert(mus.firstName);

alert(mus.lastName);

alert(mus.instrument);

}

}

});

5.

{ "listaccountsresponse" : { "count":1,"timezone":"Asia/Shanghai"}]} ] } }

Highlighter" style="font-family: Monaco,

success:function(data){

varaccounts=data.listaccountsresponse.account;//取到“account”中的数据

for(inti=0;i<accounts.length;i++){//循环后台传过来的Json数组

vardatas=accounts[i];

alert(datas.id);

alert(datas.name);

alert(datas.accounttype);

..........

}

}

});

-----这里是自己写的一个后台传值----------------------------------------------------------------------------------------------------------

Js代码

1. @RequestMapping(value="/applyVm/listApplyVmCount",method={RequestMethod.GET,RequestMethod.POST})
2. publicvoidlistApplyVmCount(HttpServletRequestrequest,HttpServletResponseresponse){
3. response.setCharacterEncoding("utf-8");
4. response.setContentType("text/json;charset=UTF-8");
5. PrintWriterout=null;
6. Stringcount="";
7. try{
8. out=response.getWriter();
9. Map<String,Integer>map=applyVmService.findApplyVmCount();
10. Gsongson=newGson();
11. count=gson.toJson(map);
12. }catch(Exceptione){
13. e.printstacktrace();
14. }
15. out.print(count);
16. out.flush();
17. }