简单的方法为php>5.4:像在Facebook的图表

$Data = array('a' => 'apple', 'b' => 'banana', 'c' => 'catnip');
$json= json_encode($Data, JSON_PRETTY_PRINT);
header('Content-Type: application/json');
print_r($json);

浏览器中的结果

{
    "a": "apple",
    "b": "banana",
    "c": "catnip"
}

如果你在firefox上安装JSONovich。我所知道的并不是一个真正的PHP解决方案，但它可以用于开发/调试目的。

这是我自己使用的函数，api就像json_encode，除了它有第三个参数exclude_flags，以防你想排除一些默认标志(如JSON_UNESCAPED_SLASHES)

function json_encode_pretty($data, int $extra_flags = 0, int $exclude_flags = 0): string
{
    // prettiest flags for: 7.3.9
    $flags = JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | (defined("JSON_UNESCAPED_LINE_TERMINATORS") ? JSON_UNESCAPED_LINE_TERMINATORS : 0) | JSON_PRESERVE_ZERO_FRACTION | (defined("JSON_THROW_ON_ERROR") ? JSON_THROW_ON_ERROR : 0);
    $flags = ($flags | $extra_flags) & ~ $exclude_flags;
    return (json_encode($data, $flags));
}

有颜色全输出:微小的解决方案

代码:

$s = '{"access": {"token": {"issued_at": "2008-08-16T14:10:31.309353", "expires": "2008-08-17T14:10:31Z", "id": "MIICQgYJKoZIhvcIegeyJpc3N1ZWRfYXQiOiAi"}, "serviceCatalog": [], "user": {"username": "ajay", "roles_links": [], "id": "16452ca89", "roles": [], "name": "ajay"}}}';

$crl = 0;
$ss = false;
echo "<pre>";
for($c=0; $c<strlen($s); $c++)
{
    if ( $s[$c] == '}' || $s[$c] == ']' )
    {
        $crl--;
        echo "\n";
        echo str_repeat(' ', ($crl*2));
    }
    if ( $s[$c] == '"' && ($s[$c-1] == ',' || $s[$c-2] == ',') )
    {
        echo "\n";
        echo str_repeat(' ', ($crl*2));
    }
    if ( $s[$c] == '"' && !$ss )
    {
        if ( $s[$c-1] == ':' || $s[$c-2] == ':' )
            echo '<span style="color:#0000ff;">';
        else
            echo '<span style="color:#ff0000;">';
    }
    echo $s[$c];
    if ( $s[$c] == '"' && $ss )
        echo '</span>';
    if ( $s[$c] == '"' )
          $ss = !$ss;
    if ( $s[$c] == '{' || $s[$c] == '[' )
    {
        $crl++;
        echo "\n";
        echo str_repeat(' ', ($crl*2));
    }
}
echo $s[$c];

我也有同样的问题。

不管怎样，我只是在这里使用了json格式代码:

http://recursive-design.com/blog/2008/03/11/format-json-with-php/

能满足我的需要。

还有一个更加维护的版本:https://github.com/GerHobbelt/nicejson-php

我从Composer: https://github.com/composer/composer/blob/master/src/Composer/Json/JsonFile.php和nicejson: https://github.com/GerHobbelt/nicejson-php/blob/master/nicejson.php中获取代码 Composer代码很好，因为它从5.3到5.4的更新很流畅，但它只编码对象，而nicejson需要json字符串，所以我合并了它们。代码可以用来格式化json字符串和/或编码对象，我目前在Drupal模块中使用它。

if (!defined('JSON_UNESCAPED_SLASHES'))
    define('JSON_UNESCAPED_SLASHES', 64);
if (!defined('JSON_PRETTY_PRINT'))
    define('JSON_PRETTY_PRINT', 128);
if (!defined('JSON_UNESCAPED_UNICODE'))
    define('JSON_UNESCAPED_UNICODE', 256);

function _json_encode($data, $options = 448)
{
    if (version_compare(PHP_VERSION, '5.4', '>='))
    {
        return json_encode($data, $options);
    }

    return _json_format(json_encode($data), $options);
}

function _pretty_print_json($json)
{
    return _json_format($json, JSON_PRETTY_PRINT);
}

function _json_format($json, $options = 448)
{
    $prettyPrint = (bool) ($options & JSON_PRETTY_PRINT);
    $unescapeUnicode = (bool) ($options & JSON_UNESCAPED_UNICODE);
    $unescapeSlashes = (bool) ($options & JSON_UNESCAPED_SLASHES);

    if (!$prettyPrint && !$unescapeUnicode && !$unescapeSlashes)
    {
        return $json;
    }

    $result = '';
    $pos = 0;
    $strLen = strlen($json);
    $indentStr = ' ';
    $newLine = "\n";
    $outOfQuotes = true;
    $buffer = '';
    $noescape = true;

    for ($i = 0; $i < $strLen; $i++)
    {
        // Grab the next character in the string
        $char = substr($json, $i, 1);

        // Are we inside a quoted string?
        if ('"' === $char && $noescape)
        {
            $outOfQuotes = !$outOfQuotes;
        }

        if (!$outOfQuotes)
        {
            $buffer .= $char;
            $noescape = '\\' === $char ? !$noescape : true;
            continue;
        }
        elseif ('' !== $buffer)
        {
            if ($unescapeSlashes)
            {
                $buffer = str_replace('\\/', '/', $buffer);
            }

            if ($unescapeUnicode && function_exists('mb_convert_encoding'))
            {
                // http://stackoverflow.com/questions/2934563/how-to-decode-unicode-escape-sequences-like-u00ed-to-proper-utf-8-encoded-cha
                $buffer = preg_replace_callback('/\\\\u([0-9a-f]{4})/i',
                    function ($match)
                    {
                        return mb_convert_encoding(pack('H*', $match[1]), 'UTF-8', 'UCS-2BE');
                    }, $buffer);
            } 

            $result .= $buffer . $char;
            $buffer = '';
            continue;
        }
        elseif(false !== strpos(" \t\r\n", $char))
        {
            continue;
        }

        if (':' === $char)
        {
            // Add a space after the : character
            $char .= ' ';
        }
        elseif (('}' === $char || ']' === $char))
        {
            $pos--;
            $prevChar = substr($json, $i - 1, 1);

            if ('{' !== $prevChar && '[' !== $prevChar)
            {
                // If this character is the end of an element,
                // output a new line and indent the next line
                $result .= $newLine;
                for ($j = 0; $j < $pos; $j++)
                {
                    $result .= $indentStr;
                }
            }
            else
            {
                // Collapse empty {} and []
                $result = rtrim($result) . "\n\n" . $indentStr;
            }
        }

        $result .= $char;

        // If the last character was the beginning of an element,
        // output a new line and indent the next line
        if (',' === $char || '{' === $char || '[' === $char)
        {
            $result .= $newLine;

            if ('{' === $char || '[' === $char)
            {
                $pos++;
            }

            for ($j = 0; $j < $pos; $j++)
            {
                $result .= $indentStr;
            }
        }
    }
    // If buffer not empty after formating we have an unclosed quote
    if (strlen($buffer) > 0)
    {
        //json is incorrectly formatted
        $result = false;
    }

    return $result;
}