json_decode() 不起作用 [英] json_decode() not working

问题描述

我正在使用 ajax 用 JSON 发送数据，但它一直返回 null.这是我要发送的字符串:

I am using ajax to send data with JSON and it keeps returning null. Here is the string I'm sending:

{"username":"HittmanA","code":"%601234567890-%3D~!%40%23%24%25%5E%26*()_%2Bqwertyuiop%5B%5D%5CQWERTYUIOP%7B%7D%7Casdfghjkl%3B'ASDFGHJKL%22zxcvbnm%2C%2FZXCVBNM%3C%3E%3F","name":"Untitled-1"}

它是通过邮寄方式发送的.这是我发送的代码:

It is sent via post. Here is the code I send it with:

       function slash(strr){
                            var re = /([^a-zA-Z0-9])/g; 
                            var str = strr;
                            var subst = '\$1'; 
                            var st = encodeURIComponent(str.replace(re,subst));
                            console.log("st");
                            return st;
                           }
          function create() {
            var info = {};
            var code=editor.getValue();
            info.username=username;
            info.code=slash(code);
            var name=document.getElementById('projectName').value;
            name2=name;
            info.name=slash(name2);
            info=JSON.stringify(info);
            console.log(info);
            var xhttp = new XMLHttpRequest();
            xhttp.onreadystatechange = function() {
              if (xhttp.readyState == 4 && xhttp.status == 200) {
                document.getElementById("demo").innerHTML = xhttp.responseText;
              }
            };
            xhttp.open("POST", "create_project.php", true);
            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
            xhttp.send("info="+info);
          }

当它在 php 文件中收到时，它的处理方式如下:

When it gets received in the php file it is processed like this:

    $info = $_POST['info'];
    echo "<pre>".$info."</pre>";
    //$info = urldecode($info);
    $info = json_decode($info);
    echo "<pre>".$info."</pre>";

但是由于某种原因 json_decode() 不起作用.这里再次是我发送的 JSON:

However for some reason the json_decode() doest work. Again here is the JSON I'm sending:

{"username":"HittmanA","code":"%601234567890-%3D~!%40%23%24%25%5E%26*()_%2Bqwertyuiop%5B%5D%5CQWERTYUIOP%7B%7D%7Casdfghjkl%3B'ASDFGHJKL%22zxcvbnm%2C%2FZXCVBNM%3C%3E%3F","name":"Untitled-1"}

第一个回声正常工作，但第二个没有.我该如何解决这个问题?

the first echo works correctly but the second one doesn't. How do I fix this?

推荐答案

json_decode() 必须发出您没有检查的错误.json_decode() 和 json_encode() 等函数不会显示错误，您必须使用 json_last_error 并且从 PHP 5.5 开始还有 json_last_error_msg().

json_decode() must be emitting an error which you are not checking. Functions like json_decode() and json_encode() do not display errors, you must use json_last_error and since PHP 5.5 there is also json_last_error_msg().

<?php

$str = '{"username":"HittmanA","code":"%601234567890-%3D~!%40%23%24%25%5E%26*()_%2Bqwertyuiop%5B%5D%5CQWERTYUIOP%7B%7D%7Casdfghjkl%3B\'ASDFGHJKL%22zxcvbnm%2C%2FZXCVBNM%3C%3E%3F","name":"Untitled-1"}';

var_dump($str);
var_dump(json_decode($str));
var_dump(json_last_error());
var_dump(json_last_error_msg());

以上输出:

string(189) "{"username":"HittmanA","code":"%601234567890-%3D~!%40%23%24%25%5E%26*()_%2Bqwertyuiop%5B%5D%5CQWERTYUIOP%7B%7D%7Casdfghjkl%3B\'ASDFGHJKL%22zxcvbnm%2C%2FZXCVBNM%3C%3E%3F","name":"Untitled-1"}"
class stdClass#1 (3) {
  public $username =>
  string(8) "HittmanA"
  public $code =>
  string(136) "%601234567890-%3D~!%40%23%24%25%5E%26*()_%2Bqwertyuiop%5B%5D%5CQWERTYUIOP%7B%7D%7Casdfghjkl%3B\'ASDFGHJKL%22zxcvbnm%2C%2FZXCVBNM%3C%3E%3F"
  public $name =>
  string(10) "Untitled-1"
}
int(0)
string(8) "No error"

如果我们尝试解码无效的 JSON:

If we try to decode invalid JSON:

<?php

$str = 'foobar{';

var_dump($str);
var_dump(json_decode($str));
var_dump(json_last_error());
var_dump(json_last_error_msg());

以上打印:

string(7) "foobar{"
NULL
int(4)
string(16) "boolean expected"

当您尝试解码时，JSON 中肯定有错误.使用 json_* 错误消息函数检查错误.错误消息会告诉您出了什么问题，一旦您知道错误是什么，它就会直接修复.

There must be an error in the JSON when you try to decode it. Check for errors usings the json_* error message functions. The error message will tell you what's wrong and it will be straight to fix once you know what the error is.

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