Properties class also provides a storeToXML() method to output key-value pairs in XML format.Įxample code: String newAppConfigXmlFile = rootPath + "newApp.xml" ĪppProps.storeToXML(new FileOutputStream(newAppConfigXmlFile), "store to xml file")
If you don't want to write any comment, simply use null for it. Properties class provides a store() method to output key-value pairs.Įxample code: String newAppConfigPropertiesFile = rootPath + "newApp.properties" ĪppProps.store(new FileWriter(newAppConfigPropertiesFile), "store to properties file") String versionAfterRemoval = appProps.getProperty("version") ĪssertNull(versionAfterRemoval) 6. If you want to remove a key-value pair, you can use remove() method.Įxample Code: String versionBeforeRemoval = appProps.getProperty("version") ĪssertEquals("1.0", versionBeforeRemoval)
#LOCAD PROPERTY FILE TO JAVA CLASS CODE#
The code below will not work as you wish, when you use getProperty() to get its value, it will return null: appProps.put("version", 2) 5. Note that although Properties class inherits put() method and putAll() method from Hashtable class, I wouldn't recommend you use them for the same reason as for get() method: only String values can be used in Properties. String newAppDownloadAddr = appProps.getProperty("downloadAddr") String newAppName = appProps.getProperty("name")
#LOCAD PROPERTY FILE TO JAVA CLASS UPDATE#
We can use setProperty() method to update an existed key-value pair or add a new key-value pair.Įxample code: tProperty("name", "NewAppName") // update an old valueĪtProperty("downloadAddr", "// add new key-value pair The code below will throw an Exception: float appVerFloat = (float) appProps.get("version") 4. Because its get() method will return an Object value which can only be cast to String and the getProperty() method already handles the raw Object value properly for you. Note that although Properties class inherits get() method from Hashtable class, I wouldn't recommend you use it to get value. String appDownloadAddr = appProps.getProperty("downloadAddr") String appGroup = appProps.getProperty("group", "baeldung") String appName = appProps.getProperty("name", "defaultName") But if there is no such key-value pair, the former will return null, and the latter will return defaultValue instead.Įxample code: String appVersion = appProps.getProperty("version")
If the key-value pair exists, the two methods will both return the corresponding value. We can use getProperty(String key) and getProperty(String key, String defaultValue) to get value by its key. IconProps.loadFromXML(new FileInputStream(iconConfigPath)) ĪssertEquals("icon1.jpg", iconProps.getProperty("fileIcon")) 3. String iconConfigPath = rootPath + "icons.xml" Now, let's load it: String rootPath = Thread.currentThread().getContextClassLoader().getResource("").getPath() Here is an example for loading key-value pairs from an XML file – icons.xml: Load From XML Filesīesides properties files, Properties class can also load XML files which conform to the specific DTD specifications. Here are more details for Property file format. String appVersion = appProps.getProperty("version") ĪssertEquals("files", catalogProps.getProperty("c1")) Īs long as a file's content meet properties file format requirements, it can be parsed correctly by Properties class. Properties catalogProps = new Properties() ĬatalogProps.load(new FileInputStream(catalogConfigPath)) String catalogConfigPath = rootPath + "catalog" ĪppProps.load(new FileInputStream(appConfigPath)) String appConfigPath = rootPath + "app.properties" We can now load them very simply into a Properties instance: String rootPath = Thread.currentThread().getContextClassLoader().getResource("").getPath() properties“, the suffix, it's not necessary.
Notice that although the properties files are recommended to use “. Let's start with an example for loading key-value pairs from properties files we're loading two files we have available on our classpath: That's what we'll focus on in this article. Most Java application need to use properties at some point, generally to store simple parameters as key-value pairs, outside of compiled code.Īnd so the language has first class support for properties – the – a utility class designed for handling this type of configuration files. If you have a few years of experience in the Java ecosystem, and you're interested in sharing that experience with the community (and getting paid for your work of course), have a look at the "Write for Us" page.
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