PHP将数据从查询转换成json数组

问题描述：

我有一些代码查询我的数据库并返回地址数据。然后我将地址转换为json格式的纬度和经度，以便我可以使用javascript函数在谷歌地图上显示标记。总体结果是关于json数据意外结束的错误代码。我相信问题在于php文件。当我自己运行它时，会得到一个错误的页面响应。有没有人知道我为什么会遇到错误？PHP将数据从查询转换成json数组

这里是PHP代码：

$address = pg_query($conn, " 
SELECT 
    incident.address, 
    incident.city, 
    incident.state_1 
FROM 
    fpscdb001_ws_001.incident 
WHERE 
    incident.initial_symptom = 'Chrome Upgrade' AND 
    incident.is_installed != 'true';"); 

    if (!$address) { 
      echo "Query failed\n"; 
      exit; 
     } 
$arr = array(); 
while ($markers = pg_fetch_row($address)){ 
    $Lat = $xml->result->geometry->location->lat; 
    $Lon = $xml->result->geometry->location->lng; 
    $arr[] = array("lat" => $Lat, "lng" => $Lng); 
} 
echo json_encode($arr); 

    } 
pg_close($conn);

这里是JavaScript：

var xhr = new XMLHttpRequest(); 
xhr.onreadystatechange = function() { 
if (xhr.readyState == 4) { 
    var arr = JSON.parse(xhr.responseText); 
    if(Array.isArray(arr)){ 
     showMarkers(arr); 
    } 
} 
} 
xhr.open('GET', 'markers.php', true); 
xhr.send(); 

function showMarkers(locations){ 
var markers = locations.map(function(location, i) { 
    return new google.maps.Marker({ 
    position: location, 
    label: labels[i % labels.length] 
    }); 
}); 

var markerCluster = new MarkerClusterer(map, markers, {imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'});}}

控制台：未捕获的语法错误：在JSON.parse（JSON输入意外结束）在XMLHttpRequest的.xhr.onreadystatechange（map.php：36）

为什么你需要一个数组？只需传递一个具有两个值的字符串即可。 – Stuart

如果错误发生是因为您的错误响应不是JSON格式会怎么样？我指的是你回应的地方'''查询失败\ n“' –

你可以console.log（）xhr.responseText的内容并粘贴结果吗？ – Logar

答

您正在剔除$ Lon并使用$ Lng：

$Lon = $xml->result->geometry->location->lng; 
    $arr[] = array("lat" => $Lat, "lng" => $Lng);

而且，问题的标题是错误的：你想JSON数组，而不是XML阵列

谢谢，我没有理解。我对代码进行了更改，但仍然出现错误。 – KevMoe

答

示例代码，请测试。

markers.php

<?php 

$p = [ 

     ['lat'=>-37.774785, 'lng'=> 145.137978], 
     ['lat'=>-37.819616, 'lng'=> 144.968119], 
     ['lat'=>-38.330766, 'lng'=> 144.695692], 
     ['lat'=>-39.927193, 'lng'=> 175.053218], 
     ['lat'=>-41.330162, 'lng'=> 174.865694], 
     ['lat'=>-42.734358, 'lng'=> 147.439506], 
     ['lat'=>-42.734358, 'lng'=> 147.501315], 

     ]; 

echo json_encode($p);

markers.html

<!DOCTYPE html> 
<html> 
    <head> 
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no"> 
    <meta charset="utf-8"> 
    <title>Marker Clustering</title> 
    <style> 
     /* Always set the map height explicitly to define the size of the div 
     * element that contains the map. */ 
     #map { 
     height: 100%; 
     } 
     /* Optional: Makes the sample page fill the window. */ 
     html, body { 
     height: 100%; 
     margin: 0; 
     padding: 0; 
     } 
    </style> 
    </head> 
    <body> 
    <div id="map"></div> 

<script> 
function initMap() { 

     var map = new google.maps.Map(document.getElementById('map'), { 
      zoom: 3, 
      center: {lat: -28.024, lng: 140.887} 
     }); 

     var labels = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; 

     var markers = locations.map(function(location, i) { 
      return new google.maps.Marker({ 
      position: location, 
      label: labels[i % labels.length] 
      }); 
     }); 

     // Add a marker clusterer to manage the markers. 
     var markerCluster = new MarkerClusterer(map, markers, 
      {imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'}); 
     } 

var locations; 
var xhr = new XMLHttpRequest(); 
xhr.onreadystatechange = function() { 
if (xhr.readyState == 4) { 
    var arr = JSON.parse(xhr.responseText); 
    if(Array.isArray(arr)){ 
     locations = arr; 
    } 
    } 
} 
xhr.open('GET', 'markers.php', true); 
xhr.send(); 

    </script> 
    <script src="https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/markerclusterer.js"></script> 
    <script async defer src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAkUrEm_U0QWg1QNryI1O5FpB0xAvffJ7I&callback=initMap"></script> 
</body> 
</html>

两个方法：

markers.php

<?php 

$p = [ 

     ['lat'=>-37.774785, 'lng'=> 145.137978], 
     ['lat'=>-37.819616, 'lng'=> 144.968119], 
     ['lat'=>-38.330766, 'lng'=> 144.695692], 
     ['lat'=>-39.927193, 'lng'=> 175.053218], 
     ['lat'=>-41.330162, 'lng'=> 174.865694], 
     ['lat'=>-42.734358, 'lng'=> 147.439506], 
     ['lat'=>-42.734358, 'lng'=> 147.501315], 

     ]; 

return json_encode($p);

markers_html.php

<!DOCTYPE html> 
<html> 
    <head> 
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no"> 
    <meta charset="utf-8"> 
    <title>Marker Clustering</title> 
    <style> 
     /* Always set the map height explicitly to define the size of the div 
     * element that contains the map. */ 
     #map { 
     height: 100%; 
     } 
     /* Optional: Makes the sample page fill the window. */ 
     html, body { 
     height: 100%; 
     margin: 0; 
     padding: 0; 
     } 
    </style> 
    </head> 
    <body> 
    <div id="map"></div> 


<script> 
function initMap() { 

     var map = new google.maps.Map(document.getElementById('map'), { 
      zoom: 3, 
      center: {lat: -28.024, lng: 140.887} 
     }); 

     var labels = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'; 

     var markers = locations.map(function(location, i) { 
      return new google.maps.Marker({ 
      position: location, 
      label: labels[i % labels.length] 
      }); 
     }); 

     // Add a marker clusterer to manage the markers. 
     var markerCluster = new MarkerClusterer(map, markers, 
      {imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'}); 
     } 

var locations = <?=include("markers.php");?>; 

    </script> 
    <script src="https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/markerclusterer.js"></script> 
    <script async defer src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAkUrEm_U0QWg1QNryI1O5FpB0xAvffJ7I&callback=initMap"></script> 
</body> 
</html>

PHP将数据从查询转换成json数组

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