JavaScript无法从PHP json_encode找到JSON数据

Question

The idea here is to automatically load (or load at all) my index page with some products out of a MySQL database table.

Firstly, my PHP.

<?php
header('Content-Type: application/json');
require_once 'classloader.php';
$db = new Database();

$items = $db->getRows('SELECT * FROM products');

foreach($items as $eachItem){
    $itemsJSON = new Item($eachItem->product_name, $eachItem->product_quantity, $eachItem->product_cost);
    echo json_encode($itemsJSON);
}

This seems to be working great, and gives me two properly encoded JSON objects of my Item class.

{"name":"Slippers","quantity":"3","cost":"4.00"}
{"name":"Gloves","quantity":"5","cost":"9.00"}

My JavaScript looks like this(and many other similar variations)

$(document).ready(function () {
    $.post( "productloader.php", function( data ) {
        $( "#result" ).html( data );
    });
});

I'm not sure why it is not working. I did not want to use $.getJSON() because there is no query string to work with, so I'd assume I would need $.post() .

It seems like this is a pretty common issue, but I've not found a solution yet. Any help would be appreciated. Thank you.

Answer 1

You can't json_encode() each item separately. The data you're sending to the browser is not valid JSON, just many little chunks of valid JSON one after the other. Build an array inside your loop and then encode the whole thing. See also http://jsonlint.com/

<?php
header('Content-Type: application/json');
require_once 'classloader.php';
$db = new Database();

$items = $db->getRows('SELECT * FROM products');

foreach($items as $eachItem){    
    $itemsJSON[] = new Item($eachItem->product_name, $eachItem->product_quantity, $eachItem->product_cost);
}

echo json_encode($itemsJSON);

Answer 2

In your method of AJAX , you're outputting multiple JSON strings while the js side is expecting 1 string (data) . Try removing your for loop to just:

echo json_encode($items);

Answer 3

You are creating JSON for each row, so you are getting separate JSON objects for each row in front end.

You should put all row in to and array and create the JSON object outside the loop, and echo the encoded JSON string.

<?php
    $allitem = $db->getRows('SELECT * FROM products');
    $itemArr=array();
    foreach($allitem as $item){    
        array_push( $itemArr ,  new Item($item->product_name, $item->product_quantity, $item->product_cost) );
    }

    echo json_encode($itemArr);
?>

or

    $allitem = $db->getRows('SELECT * FROM products');
    echo json_encode($allitem );