javascript - 多个 JSON 文件调用

Question

谁能帮我解决以下问题。我有 2 个 JSON 文件:

1. names.json:其中包含每个人的所有姓名年龄和地址数组(如果有多个居住地)。 { "people": [ { "name":"Peter Gabriel", "age":42, "address": ["location1","location2","location3"] }, { "name":"Mark Vincent", "age":"25", "address": ["location4","location5"] } ] }

2. data.json:包含所有地址详细信息 { "location1": { "country":"Switzerland", "street":"some Avenue", "number": 32 }, "location2": { "country":"Latvia", "street":"some Street", "number": 43 }, "location3": { "country":"Denmark", "street":"some Road", "number": 16 }, "location4": { "country":"Austria", "street":"some Avenue", "number": 54 }, "location5": { "country":"Poland", "street":"some Avenue", "number": 23 } } 我需要将 data.json 文件数据放在全局中并在 names.json 之前加载，但由于 JSON 加载是一个异步函数，我该怎么做。

   var jsonAddressData = [];
   function main()
   { 
       loadNamesJSON(function(response) {
           jsonAddressData = JSON.parse(response);
       });
   
   
       loadNamesJSON(function(response) {
           var jsonPeopleData = JSON.parse(response);
           var addressDetail=[];
   
           for(var i in jsonPeopleData.people){
               // ACCESS ADDRESS OBJECT DETAILS HERE
              for(var j in jsonPeopleData.people[i].address){
                  if (jsonPeopleData.people[i].address[j] in jsonAddressData){
   
                      addressDetail.append(jsonAddressData[jsonPeopleData.people[i].address[j]])
                  }
               }
           }
       });
   }
   
   function loadNamesJSON(callback) {
       var request = new XMLHttpRequest();
       request.overrideMimeType("application/json");
       request.open('GET', 'names.json', true); 
   
       request.onreadystatechange = function () {
           if (request.readyState === 4 && request.status ===200) {
               callback(request.responseText);
           }
       };
       request.send(null);
   }
   
   function loadDataJSON(callback) {
       var request = new XMLHttpRequest();
       request.overrideMimeType("application/json");
       request.open('GET', 'data.json', true); 
   
       request.onreadystatechange = function () {
           if (request.readyState === 4 && request.status ===200) {
               callback(request.responseText);
           }
       };
       request.send(null);
   }
   

Answer 1

在原始 JavaScript 中你可以这样做:

function phpEncode(obj){
  var r = [];
  if(obj instanceof Array){
    for(var i=0,l=obj.length; i<l; i++){
      r.push(phpEncode(obj[i]));
    }
    return '%5B'+r.join(',')+'%5D';
  }
  else if(typeof obj === 'object' && obj){
    for(var i in obj){
      if(obj.hasOwnProperty(i)){
        var v = obj[i], s;
        if(typeof v === 'object' && v){
          s = encodeURIComponent('"'+i.replace('"', '\\"')+'":')+phpEncode(v);
        }
        else{
          v = typeof v === 'string' ? '"'+v.replace('"', '\"')+'"' : v;
          s = encodeURIComponent('"'+i.replace('"', '\\"')+'":'+v);
        }
        r.push(s);
      }
    }
    return '%7B'+r.join(',')+'%7D';
  }
  else{
    r = typeof obj === 'string' ? '"'+obj.replace('"', '\\"')+'"' : obj;
    return ''+r;
  }
}
function phpDecode(url){
  return eval('('+decodeURIComponent(url)+')');
}
function post(send, where, success, context){
  var x = new XMLHttpRequest || new ActiveXObject('Microsoft.XMLHTTP');
  var c = context || this;
  x.open('POST', where); x.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
  x.onreadystatechange = function(){
    if(x.readyState === 4 && x.status === 200){
      if(success)success.call(c, phpDecode(x.responseText));
    }
  }
  if(typeof send === 'object' && send && !(send instanceof Array)){
    var r = [];
    for(var p in send){
      r.push(encodeURIComponent(p)+'='+phpEncode(send[p]));
    }
    x.send(r.join('&'));
  }
  else{
    throw new Error('send must be an Object');
  }
}
post({}, 'data.json', function(obj1){
  // obj1 holds data.json Object
  post({}, 'names.json', function(obj2){
    // obj2 holds names.json Object
  });
});

请随意更改上面的代码以满足您的需求。例如我正在使用 POST 请求。当然，这对你来说并不重要。

如果使用 jQuery:

$.getJSON('data.json', function(obj1){
  // obj1 holds data.json Object
  $.getJSON('names.json', function(obj2){
    // obj2 holds names.json Object
  });
});

需要注意的重要一点是 AJAX 是异步的，因此后面的所有代码都必须位于 success 函数内。换句话说，如果你这样做:

$.getJSON('data.json', function(obj1){
  var whatever = obj1;
  // obj1 holds data.json Object
  $.getJSON('names.json', function(obj2){
    // obj2 holds names.json Object
  });
});
console.log(whatever);

console.log(whatever) 将返回 undefined，因为除非 AJAX 发生得非常快，否则它不会发生。无论如何，你需要一段时间才能完全理解这些东西。祝你好运。