为什么 jqXHR.responseText 返回字符串而不是 JSON 对象？
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Why is jqXHR.responseText returning a string instead of a JSON object?
提问by Tjorriemorrie
I have an $.ajax() request with the dataType set to "json." The server is returning JSON with the correct mime type of "application/json." And yet the responseText in my jqXHR object is always a string. What am I doing wrong? Is this how it's supposed to work?
我有一个 $.ajax() 请求，其中 dataType 设置为“json”。服务器正在返回具有正确 mime 类型“application/json”的 JSON。然而，我的 jqXHR 对象中的 responseText 始终是一个字符串。我究竟做错了什么？这是它应该如何工作？
Here's how I'm making the call:
这是我拨打电话的方式：
var options = {
dataType:'json',
type: 'GET',
url: "http://example.com/api/"
};
var key = "PassToCallback";
var jqXHRObject = $.ajax(options).then(
function(data, textStatus, jqXHR, key) {
this.success(data, textStatus, jqXHR, key);
},
function(jqXHR, textStatus, errorThrown) {
this.error(jqXHR, textStatus, errorThrown);
}
);
console.log(jqXHRObject.getResponseHeader("content-type")); // application/json
console.log(typeof jqXHRObject.responseText); // string
So I have have to do a $.parseJSON(jqXHRObject.responseText)to get an actual object. This seems unnecessary as $.ajax() should be automatically converting responseText according to the docs. Thanks!
所以我必须做一个$.parseJSON(jqXHRObject.responseText)才能得到一个实际的对象。这似乎没有必要，因为 $.ajax() 应该根据文档自动转换 responseText 。谢谢！
回答by Tjorriemorrie
I had the same problem. I returns a string because it formulated from an exception. E.g. I use a kernel listener with serialization to json on my Symfony2 project. Which is correct for proper REST headers.
我有同样的问题。我返回一个字符串，因为它是从异常中制定的。例如，我在我的 Symfony2 项目中使用了一个带有序列化到 json 的内核监听器。这对于正确的 REST 标头是正确的。
Anyway, just parse it; this works for me:
无论如何，只需解析它；这对我有用：
$.ajaxSetup({
"error": function(jqXHR, status, thrownError) {
alert('error');
var responseText = jQuery.parseJSON(jqXHR.responseText);
console.log(responseText);
}
});
回答by chridam
Try
尝试
$.ajaxSetup({
"error": function(jqXHR, status, thrownError) {
alert('error');
console.log(jqXHR.responseJSON);
}
});
回答by kcbanner
You are using $.ajax in a way the docs don't describe. Using jsonas the dataType just means that the data passed to the successcallback will be parsed. Use it like this:
您正在以文档未描述的方式使用 $.ajax。使用json的具体的数据类型只是意味着传递给数据success的回调将被解析。像这样使用它：
$.ajax({
dataType:'json',
type: 'GET',
url: "http://example.com/api/"
success: function(data, textStatus, jqXHR) {
// `data` contains parsed JSON
},
error: function(jqXHR, textStatus, errorThrown) {
// Handle any errors
}
});
回答by michaeltomer
I don't see anything in the documentation that suggests responseText would be anything other than exactly what the name implies: text.
我在文档中没有看到任何内容表明 responseText 可能不同于名称所暗示的内容：text。
Why not just use .getJSON? That would get rid of half of the code you wrote, and it'll convert the response to JSON. Win/win.
为什么不直接使用.getJSON？这将删除您编写的一半代码，并将响应转换为 JSON。赢/赢。
回答by Aravindh Gopi
Step 1: Stringify the jqXHR
第 1 步：将 jqXHR 字符串化
var errorString = JSON.stringify(jqXHR.responseText);
Step 2: change that string to Jquery Object
第 2 步：将该字符串更改为 Jquery 对象
var $errorObj = $(errorString);
Step 3: Find and get what part of responseText you want.
第 3 步：查找并获取您想要的 responseText 部分。
var errorMessage = $errorObj.find('p').eq(1).text();
/* Here Im finding `Message:` thrown by the server, which is inside <p> tag */
Thats it.
就是这样。
$.ajax( /* ... */ ).fail( function(jqXHR, textStatus, errorThrown) {
var errorString = JSON.stringify(jqXHR.responseText);
var $errorObj = $(errorString);
var errorMessage = $errorObj.find('p').eq(1).text();
alert(errorMessage);
} );
