com.github.javaclub.configcenter.client.util.PropUtil Maven / Gradle / Ivy
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/*
* @(#)PropUtil.java 2009-2-19
*
* Copyright (c) 2009 by gerald. All Rights Reserved.
*/
package com.github.javaclub.configcenter.client.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.ResourceBundle;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A utility class for processing Properties
*
* @author Gerald Chen
*/
public class PropUtil {
private static final Logger log = LoggerFactory.getLogger(PropUtil.class);
/**
* Holds configuration objects
*/
private static Map map = new HashMap();
/**
* The filename of default configuration file
*/
private static final String DEFAULT_CONFIG_FILE = "server";
private PropUtil() {
}
/**
* Gets system property value by key,return value valIfNull if
* null.
*
* @param key the key
* @return
*/
public static String getSystemProperty(String key, String valIfNull) {
String val = getSystemProperty(key);
return val == null ? valIfNull : val;
}
/**
*
* Gets a System property, defaulting to null if the property
* cannot be read.
*
*
*
* If a SecurityException is caught, the return value is
* null and a message is written to System.err.
*
*
* @param property the system property name
* @return the system property value or null if a security
* problem occurs
*/
public static String getSystemProperty(String property) {
try {
return System.getProperty(property);
} catch (SecurityException ex) {
// we are not allowed to look at this property
System.err.println("Caught a SecurityException reading the system property '"
+ property
+ "'; the SystemUtils property value will default to null.");
return null;
}
}
/**
* Loads Properties from a file.
*
* @param filepath The target file's path
* @return java.util.Properties
*/
public static Properties load(String filepath) {
if (null == filepath || 0 == filepath.length()) {
throw new IllegalArgumentException("the path must not be empty.");
}
File file = new File(filepath);
return load(file);
}
public static Properties load(File file) {
if (!(file.exists() && file.isFile())) {
throw new IllegalArgumentException("the path [" + file.getAbsolutePath()
+ "] is not a correct file path.");
}
Properties prop = new Properties();
InputStream input = null;
try {
input = new FileInputStream(file);
prop.load(input);
} catch (IOException e) {
if (log.isWarnEnabled()) {
log.warn("load file [" + file.getAbsolutePath() + "] failed.");
}
} finally {
if(null != input) {
try {
input.close();
} catch (Exception e) {
}
}
}
return prop;
}
/**
* Loads properties from a classpath resource
*
* @param props
* @param resource e.g. conf/props/test.properties
* @param throwExceptionIfNotFound
* @return loaded properties
*/
public static Properties loadFromClassPath(String resource,
boolean throwExceptionIfNotFound) {
URL url = PropUtil.class.getClassLoader().getResource(resource);
if (url == null) {
if (throwExceptionIfNotFound) {
throw new IllegalStateException(
"Could not find classpath properties resource: "
+ resource);
} else {
return new Properties();
}
}
try {
Properties props = new Properties();
InputStream is = url.openStream();
try {
props.load(url.openStream());
} finally {
is.close();
}
return props;
} catch (IOException e) {
throw new RuntimeException(
"Could not read properties at classpath resource: "
+ resource, e);
}
}
public static Properties setValue(String filepath, String key, String value) throws IOException {
File file = new File(filepath);
if(!file.exists()) {
throw new RuntimeException("The properties file [" + filepath + "] doesn't exist.");
}
FileOutputStream out = null;
try {
Properties p = new Properties();
p.load(new FileInputStream(file));
p.setProperty(key, value);
// save to file
out = new FileOutputStream(file);
p.store(out, "Modified on " + new Date());
return p;
} finally {
if(null != out) {
try {
out.close();
} catch (Exception e) {
}
}
}
}
/**
* Merges multiple {@link Properties} instances into one
*
* @param mode merge mode
* @param sources properties to merge
* @return new instance of {@link Properties} containing merged values
*/
public static Properties merge(MergeMode mode, Properties... sources) {
Properties props = new Properties();
for (int i = 0; i < sources.length; i++) {
final Properties source = sources[i];
for (Entry prop : source.entrySet()) {
final boolean exists = props.containsKey(prop.getKey());
boolean set = false;
switch (mode) {
case MERGE:
set = true;
break;
case OVERRIDE_ONLY:
set = exists;
break;
}
if (set || i == 0) {
props.put(prop.getKey(), prop.getValue());
}
}
}
return props;
}
/**
* Loads the default properties file.
*
* @return
*/
public synchronized static Configuration getConfiguration() {
return getConfiguration(DEFAULT_CONFIG_FILE);
}
/**
* Loads a specified properties file.
*
* For example,if properties file 'database.properties' is in the package
* "com.jsoft.rs", you can do as following:
*
*
* String val = PropUtil.getConfiguration("com/jsoft/rs/database").getValue(
* "database.username");
*
*
* @param config The bundle properties file's path
* @return Configuration object
*/
public synchronized static Configuration getConfiguration(String config) {
Configuration configuration = map.get(config);
if (null == configuration) {
configuration = new Configuration(config);
map.put(config, configuration);
}
return configuration;
}
/**
* Merge mode
*/
public static enum MergeMode {
OVERRIDE_ONLY,
MERGE
}
public static class Configuration {
private ResourceBundle resourceBundle;
public Configuration(String config) {
resourceBundle = ResourceBundle.getBundle(config);
}
public String getValue(String key) {
return (resourceBundle.getString(key));
}
public byte byteValue(String key) {
return Byte.parseByte(getValue(key));
}
public short shortValue(String key) {
return Short.parseShort(getValue(key));
}
public int intValue(String key) {
return Integer.parseInt(getValue(key));
}
public long longValue(String key) {
return Long.parseLong(getValue(key));
}
public float floatValue(String key) {
return Float.parseFloat(getValue(key));
}
public double doubleValue(String key) {
return Double.parseDouble(getValue(key));
}
public boolean boolValue(String key) {
return "true".equals(getValue(key));
}
}
public static void main(String[] args) throws IOException {
Properties p = System.getProperties();
p.setProperty("压抑", "哈哈");
p.list(System.out);
File file = new File(p.getProperty("user.home") + "/utf8.txt");
if (file.exists()) {
file.createNewFile();
}
FileOutputStream out = new FileOutputStream(file);
p.store(out, null);
System.out.println(System.getProperty("java.io.tmpdir"));
}
}
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