Java封装 properties文件操作

/**
* Prop. Prop can load properties file from CLASSPATH or File object.
*/
public class Prop {

private Properties properties = null;

/**
* Prop constructor.
* @see #Prop(String, String)
*/
public Prop(String fileName) {
this(fileName, Const.DEFAULT_ENCODING);
}

/**
* Prop constructor
* <p>
* Example:<br>
* Prop prop = new Prop("my_config.txt", "UTF-8");<br>
* String userName = prop.get("userName");<br><br>
*
* prop = new Prop("com/jfinal/file_in_sub_path_of_classpath.txt", "UTF-8");<br>
* String value = prop.get("key");
*
* @param fileName the properties file's name in classpath or the sub directory of classpath
* @param encoding the encoding
*/
public Prop(String fileName, String encoding) {
InputStream inputStream = null;
try {
inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);        // properties.load(Prop.class.getResourceAsStream(fileName));
if (inputStream == null)
throw new IllegalArgumentException("Properties file not found in classpath: " + fileName);
properties = new Properties();
properties.load(new InputStreamReader(inputStream, encoding));
} catch (IOException e) {
throw new RuntimeException("Error loading properties file.", e);
}
finally {
if (inputStream != null) try {inputStream.close();} catch (IOException e) {e.printStackTrace();}
}
}

/**
* Prop constructor.
* @see #Prop(File, String)
*/
public Prop(File file) {
this(file, Const.DEFAULT_ENCODING);
}

/**
* Prop constructor
* <p>
* Example:<br>
* Prop prop = new Prop(new File("/var/config/my_config.txt"), "UTF-8");<br>
* String userName = prop.get("userName");
*
* @param file the properties File object
* @param encoding the encoding
*/
public Prop(File file, String encoding) {
if (file == null)
throw new IllegalArgumentException("File can not be null.");
if (file.isFile() == false)
throw new IllegalArgumentException("Not a file : " + file.getName());

InputStream inputStream = null;
try {
inputStream = new FileInputStream(file);
properties = new Properties();
properties.load(new InputStreamReader(inputStream, encoding));
} catch (IOException e) {
throw new RuntimeException("Error loading properties file.", e);
}
finally {
if (inputStream != null) try {inputStream.close();} catch (IOException e) {e.printStackTrace();}
}
}

public String get(String key) {
return properties.getProperty(key);
}

public String get(String key, String defaultValue) {
String value = get(key);
return (value != null) ? value : defaultValue;
}

public Integer getInt(String key) {
String value = get(key);
return (value != null) ? Integer.parseInt(value) : null;
}

public Integer getInt(String key, Integer defaultValue) {
String value = get(key);
return (value != null) ? Integer.parseInt(value) : defaultValue;
}

public Long getLong(String key) {
String value = get(key);
return (value != null) ? Long.parseLong(value) : null;
}

public Long getLong(String key, Long defaultValue) {
String value = get(key);
return (value != null) ? Long.parseLong(value) : defaultValue;
}

public Boolean getBoolean(String key) {
String value = get(key);
return (value != null) ? Boolean.parseBoolean(value) : null;
}

public Boolean getBoolean(String key, Boolean defaultValue) {
String value = get(key);
return (value != null) ? Boolean.parseBoolean(value) : defaultValue;
}

public boolean containsKey(String key) {
return properties.containsKey(key);
}

public Properties getProperties() {
return properties;
}
}

/**
* PropKit. PropKit can load properties file from CLASSPATH or File object.
*/
public class PropKit {

private static Prop prop = null;
private static final Map<String, Prop> map = new ConcurrentHashMap<String, Prop>();

private PropKit() {}

/**
* Using the properties file. It will loading the properties file if not loading.
* @see #use(String, String)
*/
public static Prop use(String fileName) {
return use(fileName, Const.DEFAULT_ENCODING);
}

/**
* Using the properties file. It will loading the properties file if not loading.
* <p>
* Example:<br>
* PropKit.use("config.txt", "UTF-8");<br>
* PropKit.use("other_config.txt", "UTF-8");<br><br>
* String userName = PropKit.get("userName");<br>
* String password = PropKit.get("password");<br><br>
*
* userName = PropKit.use("other_config.txt").get("userName");<br>
* password = PropKit.use("other_config.txt").get("password");<br><br>
*
* PropKit.use("com/jfinal/config_in_sub_directory_of_classpath.txt");
*
* @param fileName the properties file's name in classpath or the sub directory of classpath
* @param encoding the encoding
*/
public static Prop use(String fileName, String encoding) {
Prop result = map.get(fileName);
if (result == null) {
result = new Prop(fileName, encoding);
map.put(fileName, result);
if (PropKit.prop == null)
PropKit.prop = result;
}
return result;
}

/**
* Using the properties file bye File object. It will loading the properties file if not loading.
* @see #use(File, String)
*/
public static Prop use(File file) {
return use(file, Const.DEFAULT_ENCODING);
}

/**
* Using the properties file bye File object. It will loading the properties file if not loading.
* <p>
* Example:<br>
* PropKit.use(new File("/var/config/my_config.txt"), "UTF-8");<br>
* Strig userName = PropKit.use("my_config.txt").get("userName");
*
* @param file the properties File object
* @param encoding the encoding
*/
public static Prop use(File file, String encoding) {
Prop result = map.get(file.getName());
if (result == null) {
result = new Prop(file, encoding);
map.put(file.getName(), result);
if (PropKit.prop == null)
PropKit.prop = result;
}
return result;
}

public static Prop useless(String fileName) {
Prop previous = map.remove(fileName);
if (PropKit.prop == previous)
PropKit.prop = null;
return previous;
}

public static void clear() {
prop = null;
map.clear();
}

public static Prop getProp() {
if (prop == null)
throw new IllegalStateException("Load propties file by invoking PropKit.use(String fileName) method first.");
return prop;
}

public static Prop getProp(String fileName) {
return map.get(fileName);
}

public static String get(String key) {
return getProp().get(key);
}

public static String get(String key, String defaultValue) {
return getProp().get(key, defaultValue);
}

public static Integer getInt(String key) {
return getProp().getInt(key);
}

public static Integer getInt(String key, Integer defaultValue) {
return getProp().getInt(key, defaultValue);
}

public static Long getLong(String key) {
return getProp().getLong(key);
}

public static Long getLong(String key, Long defaultValue) {
return getProp().getLong(key, defaultValue);
}

public static Boolean getBoolean(String key) {
return getProp().getBoolean(key);
}

public static Boolean getBoolean(String key, Boolean defaultValue) {
return getProp().getBoolean(key, defaultValue);
}

public static boolean containsKey(String key) {
return getProp().containsKey(key);
}
}