使用stringify设置对象并将其获取到本地存储?

问题描述

创建一个名为car的对象:

Creating an object called car:

function car(temp){

    this.brand=temp[0];
    this.color=temp[1];
    this.year=temp[2];
}

var temp = ['Skoda', 'Red', '2012'];
car = new car(temp);

1. 设置对象并从localStorage中读取后进行字符串化:

1. Setting object and stringify after reading from localStorage:

localStorage.setItem('car',car);
car = localStorage.getItem('car');
car = JSON.stringify(car);

stringify后的汽车-----------------> file:///android_asset/www/...上的[object Object]

car after stringify-----------------> [object Object] at file:///android_asset/www/...

将对象字符串化并在其后将对象设置为localStorage: localStorage.setItem('car'，JSON.stringify(car));car = localStorage.getItem('car');

Stringify object and Setting object to localStorage after it:localStorage.setItem('car',JSON.stringify(car));car = localStorage.getItem('car');

stringify后的汽车----------------->"{\" brand \:\" Skoda \，\" color \:\" Red \，\"year \":\"2012 \"}在file:///android_asset/www/...

car after stringify-----------------> "{\"brand\":\"Skoda\",\"color\":\"Red\",\"year\":\"2012\"}" at file:///android_asset/www/...

问题1:为什么在对对象进行字符串化时顺序会有所不同?

Question 1: Why does it make difference what is the order when you stringify the object?

问题2:为什么我不能使用像这样的字符串化对象:

Question 2: Why can't I use stringified object like that:

08-21 11:49:14.860: I/Web Console(9642): car after stringify----------------->     {"brand":"Skoda","color":"Red","year":"2012"}

console.log("car.brand ----->" + car.brand);car.name ----->未定义

console.log("car.brand----->" +car.brand);car.name----->undefined

推荐答案

根据我的理解，一旦字符串化了对象，就无法使用它，因为它不再是对象.这是一个字符串.

From my understanding you can't use your stringified object once it's been stringified because it's no longer an object. It's a String.

因此，当您尝试对字符串执行 car.brand 时，没有属性 brand .

So when you try to do car.brand on the string there is no property brand.

我个人认为，这样做是好的习惯.

Personally, good practice in my opinion would be to do.

 function car(temp){
     this.brand=temp[0];
     this.color=temp[1];
     this.year=temp[2];
 }

 var temp = ['Skoda', 'Red', '2012'];
 car = new car(temp);

 localStorage.setItem('car',JSON.stringify(car));
 car = localStorage.getItem('car');
 car = JSON.parse(car);

这意味着汽车对象现在不是字符串而是对象.

This means the car object is now not a string but an object.

执行此操作时，还要使用stringify写入本地存储，并使用parse读取.

When doing this also write to local storage using stringify and read using parse.

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