Json字符串
Json指的是JavaScript对象表示法（javaScript Object Notation）
Json是轻量级的文本数据交换格式
Json独立于语言
Json具有自我描述性，更容易理解
Json字典
相当于java的map
{“firstName”:“Bill”,“lastName”:“Gates”}
第二种字典格式：
{
‘‘employees’’:[
{“firstName”:“Bill”,“lastName”:“Gates”},
{“firstName”:“aaa”,“lastName”:“bbb”},
{“firstName”:“ccc”,“lastName”:“ddd”}
]
}
Json数组
[
{“firstName”:“Bill”,“lastName”:“Gates”},
{“firstName”:“aaa”,“lastName”:“bbb”},
{“firstName”:“ccc”,“lastName”:“ddd”}
]
js中json对象和字符串相互转换
<script>
//1.json字符串转成对象
var str1='{"firstName":"wei","lastName":"zhang"}';
var jsonObj=JSON.parse(str1);//把字符串转成对象
//通过调用对象的属性获取值
console.log(jsonObj.firstName);
console.log(jsonObj.lastName);
//2.json对象转成字符串
var str2=JSON.stringify(jsonObj);
console.log(str2);
//3.遍历json数组
var str3='[{"firstName":"Bill","lastName":"Gates"},{"firstName":"aaa","lastName":"bbb"}{"firstName":"ccc","lastName":"ddd"}]'
//把字符串转成对象数组
var persons=JSON.parse(str3);
for(var i=0;i<persons.length;i++){
var p=persons[i];
console.log(p.lastName+' '+p.firstName);
}
</script>
