JSON應知應會

JSON簡介

簡介：
JSON（JavaScriptObject Notation）、輕量級數據交換格式、很是適合於服務器與 JavaScript 的交互。

JSON兩種格式：

一、對象
對象是一個無序的「‘名稱/值’對」集合。一個對象以「{」（左括號）開始，「}」（右括號）結束。每一個「名稱」後跟一個「:」（冒號）；「‘名稱/值’ 對」之間使用「,」（逗號）分隔。

var person = { "name":"huochai", "age":29, "school":{ "name":"diankeyuan", "location":"beijing" }};

二、數組
數組是值（value）的有序集合。一個數組以「[」（左中括號）開始，「]」（右中括號）結束。值之間使用「,」（逗號）分隔。

var students =  
              [  
                     {"sno":"001","name":"jack","age":130},  
                     {"sno":"002","name":"tame","age":120},  
                     {"sno":"003","name":"cule","age":110},  
              ];

一些JSON實例

var person = { "name":"huochai", "age":29, "school":{ "name":"diankeyuan", "location":"beijing" }};
        var strJson = '{ "name":"huochai", "age":29, "school":{ "name":"diankeyuan", "location":"beijing" }}';
        var aa = 'abc';
        var bb = ['baidu','taobao'];
        var cc = {'persons': ['zhangsan','lisi']};
        var students =
                [
                    {"sno":"001","name":"jack","age":130},
                    {"sno":"002","name":"tame","age":120},
                    {"sno":"003","name":"cule","age":110},
                ];

        var personOther = JSON.parse(strJson);

        alert(personOther.age);

JSON對象

　　JSON之因此流行，是由於能夠把JSON數據結構解析爲有用的javascript對象

　　ECMAScript5對解析JSON的行爲進行了規範，定義了全局對象JSON

　　JSON對象有兩個方法：stringify()和parse()。這兩個方法分別用於把JavaScript對象序列化爲JSON字符串和把JSON字符串解析爲原生JavaScript值

stringify()

var strPerson = JSON.stringify(person);
alert(strPerson);

var strStudents = JSON.stringify(students);
alert(strStudents);

parse()

　　JSON.parse方法用於將JSON字符串轉化成對象

var strPerson = JSON.stringify(person);
var personObj = JSON.parse(strPerson);

var strStudents = JSON.stringify(students);
var studentsObj = JSON.parse(strStudents);

對應的java表示：

public class Person {
    public String name;
    public int    age;
    public School school;
}

public class School {
    public String name;
    public String location;
}

利用fastjson將java對象轉換成JSON字符串

Person person = new Person();
        person.name = "huochai";
        person.age = 29;
        person.school = new School();
        person.school.name = "diankeyuan";
        person.school.location = "beijing";


        String strJson = JSON.toJSONString(person);
        System.out.println(strJson);

        Person person2 = new Person();
        person2.name = "huochai2";
        person2.age = 292;
        person2.school = new School();
        person2.school.name = "diankeyuan2";
        person2.school.location = "beijing2";

        List<Person> lst = new ArrayList<Person>();
        lst.add(person);
        lst.add(person2);


        String strJson2 = JSON.toJSONString(lst);
        System.out.println(strJson2);