【玛卜码】JavaScript JS读取JSON文件

553 05-11

JSON 是 JS 对象的字符串表示法，它使用文本表示一个 JS 对象的信息，本质是一个字符串。

1、HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Read Json File</title>
 
    <link href="https://fonts.googleapis.com/css?family=Faster+One" rel="stylesheet">
    <link rel="stylesheet" href="css/style.css">
</head>
<body>
 
<header>
 
</header>
 
<section>
 
</section>
 
<script src="js/test.js"></script>
</body>
</html>

2、js：test.js

    //获取<header>和</section>的引用
    let header = document.querySelector('header');
    let section = document.querySelector('section');
 
    //保存一个json文件访问的URL作为一个变量
    let requestURL = 'json/superheroes.json';
    //创建一个HTTP请求对象
    let request = new XMLHttpRequest();
    //使用open（）打开一个新请求
    request.open('GET', requestURL);
    //设置XHR访问JSON格式数据，然后发送请求
    // request.responseType = 'json';
    //设置XHR访问text格式数据
    request.responseType = 'text';
    request.send();
 
    //处理来自服务器的数据
    request.onload = function() {
        let superHeroesText = request.response;
        let superHeroes = JSON.parse(superHeroesText);
        // let superHeroes = request.response;
        populateHeader(superHeroes);
        showHeroes(superHeroes);
    };
 
    //对header进行定位
    function populateHeader(jsonObj) {
        let myH1 = document.createElement('h1');
        myH1.textContent = jsonObj['squadName'];
        header.appendChild(myH1);
 
        let myPara = document.createElement('p');
        myPara.textContent = 'Hometown: ' + jsonObj['hometown'] + ' //Formed: ' + jsonObj['formed'];
        header.appendChild(myPara);
    }
 
    function showHeroes(jsonObj) {
        //用heroers存储json文件里menbers的信息
        let heroes = jsonObj['members'];
 
        for (let i = 0; i < heroes.length; i++) {
            //创建一系列页面元素
            let myArticle = document.createElement('article');
            let myH2 = document.createElement('h2');
            let myPara1 = document.createElement('p');
            let myPara2 = document.createElement('p');
            let myPara3 = document.createElement('p');
            let myList = document.createElement('ul');
 
            myH2.textContent = heroes[i].name;
            myPara1.textContent = 'Secret identity: ' + heroes[i].secretIdentity;
            myPara2.textContent = 'Age: ' + heroes[i].age;
            myPara3.textContent = 'Superpowers:';
 
            let superPowers = heroes[i].powers;
            for(let j = 0; j < superPowers.length; j++) {
                let listItem = document.createElement('li');
                listItem.textContent = superPowers[j];
                myList.appendChild(listItem);
            }
 
            myArticle.appendChild(myH2);
            myArticle.appendChild(myPara1);
            myArticle.appendChild(myPara2);
            myArticle.appendChild(myPara3);
            myArticle.appendChild(myList);
            section.appendChild(myArticle);
        }
    }

3、CSS：index.css

html, body {
    margin: 0;
}
 
html {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    height: 100%;
}
 
body {
    overflow: hidden;
    height: inherit;
}
 
h1 {
    font-size: 2rem;
    letter-spacing: -1px;
    position: absolute;
    margin: 0;
    top: -4px;
    right: 5px;
 
    color: transparent;
    text-shadow: 0 0 4px white;
}

4、json文件：heros.json

{
  "squadName" : "Super hero squad",
  "homeTown" : "Metro City",
  "formed" : 2016,
  "secretBase" : "Super tower",
  "active" : true,
  "members" : [
    {
      "name" : "Molecule Man",
      "age" : 29,
      "secretIdentity" : "Dan Jukes",
      "powers" : [
        "Radiation resistance",
        "Turning tiny",
        "Radiation blast"
      ]
    },
    {
      "name" : "Madame Uppercut",
      "age" : 39,
      "secretIdentity" : "Jane Wilson",
      "powers" : [
        "Million tonne punch",
        "Damage resistance",
        "Superhuman reflexes"
      ]
    },
    {
      "name" : "Eternal Flame",
      "age" : 1000000,
      "secretIdentity" : "Unknown",
      "powers" : [
        "Immortality",
        "Heat Immunity",
        "Inferno",
        "Teleportation",
        "Interdimensional travel"
      ]
    }
  ]
}

标签： JavaScript