Red Hat Training

A Red Hat training course is available for Red Hat Fuse

2.30. Processing JSON Data

  1. To process JSON data, you must configure a JSON reader: 
    <?xml version="1.0"?>
<smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.1.xsd" xmlns:json="http://www.milyn.org/xsd/smooks/json-1.1.xsd">
 
    <json:reader/>
 
</smooks-resource-list>
  2. Set the XML names of the root, document and array elements by using the following configuration options:
    • rootName: this is the name of the root element. The default is yaml.
    • elementName: this is the name of a sequence element. The default is element.
  3. You may wish to use characters in the key name that are not allowed in the XML element name. The reader offers multiple solutions to this problem. It can search and replace white spaces, illegal characters and the number in key names that start with a number. You can also use it to replace one key name with a completely different one. The following sample code shows you how to do this: 
    <?xml version="1.0"?>
<smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.1.xsd" xmlns:json="http://www.milyn.org/xsd/smooks/json-1.1.xsd">
 
    <json:reader keyWhitspaceReplacement="_" keyPrefixOnNumeric="n" illegalElementNameCharReplacement=".">
        <json:keyMap>
            <json:key from="some key">someKey</json:key>
            <json:key from="some&key" to="someAndKey" />
        </json:keyMap>
    </json:reader>
 
</smooks-resource-list>
    • keyWhitspaceReplacement: this is the replacement character for white spaces in a JSON map key. By default this is not defined, so the reader does not automatically search for white spaces.
      Note
      Note that there is no e between Whit and space in the keyWhitspaceReplacement field name.
    • keyPrefixOnNumeric: this is the prefix character to add if the JSON node name starts with a number. By default, this is not defined, so the reader does not search for element names that start with a number.
    • illegalElementNameCharReplacement: if illegal characters are encountered in a JSON element name then they are replaced with this value.
  4. You can also configure these optional settings:
    • nullValueReplacement: this is the replacement string for JSON null values. The default is an empty string.
    • encoding: this is the default encoding of any JSON message InputStream processed by the reader. The default encoding is UTF-8.
      Note
      This feature is deprecated. Instead, you should now manage the JSON streamsource character encoding by supplying a java.io.Reader to the Smooks.filterSource() method.
  6. To configure Smooks programmatically to read a JSON configuration, use the JSONReaderConfiguratorclass: 
    Smooks smooks = new Smooks();
 
smooks.setReaderConfig(new JSONReaderConfigurator()
        .setRootName("root")
        .setArrayElementName("e"));
 
// Use Smooks as normal...