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how to read property files from external storage

I have a jar file that I run from the console. In the program itself, I have to read data from the property file, which should be in the same folder as my jar file. How can i do this ?
my code which does not work correctly:
public class ReadProperties {
String propPath = System.getProperty("app.properties");
private String message;
private String userName;
ReadProperties() {
readProperties();
}
private void readProperties() {
final FileInputStream in;
try {
in = new FileInputStream(propPath);
Properties myProps = new Properties();
myProps.load(in);
message = myProps.getProperty(Constants.MESSAGE);
userName = myProps.getProperty(Constants.USERNAME);
} catch (Exception e) {
e.printStackTrace();
}
}
public String getMessage() {
return message;
}
public String getUserName() {
return userName;
}
}

Note that the way you have coded above requires a system property to mark the file to load, passed as:
java -Dapp.properties=somefile.properties
If you intended a file called "app.properties" this requires a change to the declaration of propPath without System.getProperty
Your file handling should use try with resources to clean up afterwards with automatic close, and not hide any exception:
try (FileInputStream in = new FileInputStream(propPath)) {
// load here
}
You could provide default property values after exception, or handle by add throws IOException to the method, or append code to adapt as a runtime exception so that is is reported:
catch (Exception e) {
throw new UncheckedIOException(e);
}

How to fix ApplicationResources_fr.properties getting corrupted

I have a problem in a class I wrote. The purpose of the class is to add/remove/update for the applicationResource.properties files which the <spring:message code="key" /> uses to provide bilingual support to the website. Manually interacting with the properties files works fine, but I had a greater need and so I built in a way to allow changes to be done from the database. This has given me a very dynamic and flexible system that I can work from.
However, there is a problem. At some point after even a single change using this, the French characters end up getting changed. Such as Déconnexion becoming Déconnexion. When looked at in notepad++ its first Déconnexion and then corrupted to D\u00C3\u00A9connexion. This example was part of the original properties file.
The original (not temp) properties files have the text file encoding set to other: UTF-8. The Project properties text file encoding is set to inherited from container (Cp1252). I tried changing to Other: UTF-8 with no change.
So my question(s) is, what is causing the corruption to my French characters and how can I fix it? I have provided the complete class below.
Update: After the assistance from StephaneM in her answer I was able to track down exactly what is causing the corruption, but have not fixed it yet. The loadProperties() function in the AR Class. As soon as the temp AP files are loaded the French characters are corrupted. This makes me suspect the original process which creates the temp AP files is using a different encoding. So I will have to track it down.
package pojo;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Objects;
import java.util.Properties;
import java.util.Set;
import org.springframework.beans.factory.annotation.Autowired;
/*
* Purpose of this class is to handle all the ApplicationResource(_fr).properties interactions
* so that there is one unified location handling this, instead of code duplication.
*/
public class AR{
public final String en_path = "/ApplicationResources.properties";
public final String fr_path = "/ApplicationResources_fr.properties";
private Properties en_prop = null;
private Properties fr_prop = null;
public AR()
{
loadProperties();
}
private void loadProperties()
{
InputStream en_is = null;
InputStream fr_is = null;
try {
this.en_prop = new Properties();
this.fr_prop = new Properties();
en_is = this.getClass().getResourceAsStream(en_path);
fr_is = this.getClass().getResourceAsStream(fr_path);
en_prop.load(en_is);
fr_prop.load(fr_is);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private boolean keyExist(String mykey, String mypath) //deprecated due to better code/method
{
Properties test_prop = null;
InputStream is = null;
try {
test_prop = new Properties();
is = this.getClass().getResourceAsStream(mypath);
test_prop.load(is);
Set<Object> keys = test_prop.keySet();
for(Object k:keys) {
String key = (String)k;
//System.out.print(key + " ");
if(key.equals(mykey))
{
return true;
}
}
//System.out.println(" ");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (NullPointerException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
public boolean en_keyExist(String mykey)
{
//searches english file
loadProperties();
return en_prop.containsKey(mykey);
//return keyExist(mykey, en_path); //original method
}
public boolean fr_keyExist(String mykey)
{
//searches french file
loadProperties();
return fr_prop.containsKey(mykey);
//return keyExist(mykey, fr_path); //original method
}
public boolean en_fr_keyExist(String mykey)
{
//searches both english and french files
loadProperties();
return (en_prop.containsKey(mykey) && fr_prop.containsKey(mykey));
//return (keyExist(mykey, en_path) && keyExist(mykey, fr_path)); //original method
}
public String en_returnProperty(String mykey)
{
//returns null if key does not exist
loadProperties();
return this.en_prop.getProperty(mykey);
}
public String fr_returnProperty(String mykey)
{
//returns null if key does not exist
loadProperties();
return this.fr_prop.getProperty(mykey);
}
public void appendProperty(Properties new_en_prop,Properties new_fr_prop)
{
//note: during a test, setProperty (used in populating the properties) does not allow duplicates, it overwrites.
//So, load the existing properties, and for each new property add it
loadProperties();
for(Object key : new_en_prop.keySet())
{
en_prop.setProperty((String)key, new_en_prop.getProperty((String)key));
}
try (OutputStream en_os = new FileOutputStream(getClass().getResource(en_path).getFile(),false);)
{
en_prop.store(en_os, null);
} catch (IOException e) {
e.printStackTrace();
}
for(Object key : new_fr_prop.keySet())
{
fr_prop.setProperty((String)key, new_fr_prop.getProperty((String)key));
}
try (OutputStream fr_os = new FileOutputStream(getClass().getResource(fr_path).getFile(),false);)
{
fr_prop.store(fr_os, null);
} catch (IOException e) {
e.printStackTrace();
}
}
public boolean appendProperty(String mykey, String en_val, String fr_val) //appears to have timing error due to only saving last value
//due to timing error this function is only suitable for single additions
//due to the timing error, tried returning boolean to have it finished but was not successful
//setting the class variables to static did not solve the timing issue
{
loadProperties();
en_prop.setProperty(mykey, en_val);
try (OutputStream en_os = new FileOutputStream(getClass().getResource(en_path).getFile(),false);)
{
en_prop.store(en_os, null);
} catch (IOException e) {
e.printStackTrace();
}
fr_prop.setProperty(mykey, fr_val);
try (OutputStream fr_os = new FileOutputStream(getClass().getResource(fr_path).getFile(),false);)
{
fr_prop.store(fr_os, null);
} catch (IOException e) {
e.printStackTrace();
}
return true;
}
public void en_setProperty(String mykey, String en_val)
//suspected timing issue, use only for singular changes
{
loadProperties();
en_prop.setProperty(mykey, en_val);
try (OutputStream en_os = new FileOutputStream(getClass().getResource(en_path).getFile(),false);)
{
en_prop.store(en_os, null);
} catch (IOException e) {
e.printStackTrace();
}
}
public void fr_setProperty(String mykey, String fr_val)
//suspected timing issue, use only for singular changes
{
loadProperties();
fr_prop.setProperty(mykey, fr_val);
try (OutputStream fr_os = new FileOutputStream(getClass().getResource(fr_path).getFile(),false);)
{
fr_prop.store(fr_os, null);
} catch (IOException e) {
e.printStackTrace();
}
}
public void compareResources()
{
Properties new_en = new Properties();
Properties new_fr = new Properties();
for(Object key : en_prop.keySet())
{
new_en.setProperty((String)key, en_prop.getProperty((String)key));
}
for(Object key : fr_prop.keySet())
{
new_fr.setProperty((String)key, fr_prop.getProperty((String)key));
}
Properties temp = (Properties) new_en.clone();
for(Object key : temp.keySet())
{
if(new_fr.containsKey((String) key))
{
new_fr.remove(key);
new_en.remove(key);
}
}
for(Object key : new_en.keySet())
{
System.out.println("English only key: " + ((String)key));
}
for(Object key : new_fr.keySet())
{
System.out.println("French only key: " + ((String)key));
}
}
}
Sample use case for the class, taken directly from application, but with some editing so only the relevant parts are here
AR testing = new AR();
Properties en_prop = new Properties();
Properties fr_prop = new Properties();
final String test_prod_cur = "{call BILINGUAL_VALUES(?)}";
ResultSet rs = null;
try (
Connection connection = jdbcTemplate.getDataSource().getConnection();
CallableStatement callableStatement = connection.prepareCall(test_prod_cur);
)
{
callableStatement.registerOutParameter(1, OracleTypes.CURSOR);
callableStatement.executeUpdate();
rs = (ResultSet) callableStatement.getObject(1);
while (rs.next())
{
String thead = rs.getString(1);
en_prop.setProperty(keyheader+thead, rs.getString(2));
fr_prop.setProperty(keyheader+thead, rs.getString(3));
//testing.appendProperty(keyheader+thead, rs.getString(2), rs.getString(3)); //has a timing issue, ends up only appending final value
}
}
catch (SQLException e)
{
System.out.println("SQLException - bilingual values");
System.out.println(e.getMessage());
}
testing.appendProperty(en_prop, fr_prop);

Regarding this question: "what is causing the corruption to my French characters and how can I fix it?", the answer is in the documentation ( Properties.store() ):
public void store(OutputStream out,
String comments)
throws IOException
Writes this property list (key and element pairs) in this Properties
table to the output stream in a format suitable for loading into a
Properties table using the load(InputStream) method.
Properties from the defaults table of this Properties table (if any)
are not written out by this method.
This method outputs the comments, properties keys and values in the
same format as specified in store(Writer), with the following
differences:
The stream is written using the ISO 8859-1 character encoding.
Characters not in Latin-1 in the comments are written as \uxxxx for their appropriate unicode hexadecimal value xxxx.
Characters less than \u0020 and characters greater than \u007E in property keys or values are written as \uxxxx for the appropriate hexadecimal value xxxx.

I am not the only person who has faced this issue, I managed to find another question and it was one of the answers that lead me to my solution. I have to thank another site for letting me know what to include.
There are only four added or changed lines, I will list them, and then give a complete function.
import java.io.Reader;
Reader reader = new InputStreamReader(fr_is, "UTF-8");
fr_prop.load(reader); //instead of fr_prop.load(fr_is);
reader.close();
The complete function
import java.io.Reader;
private void loadProperties()
{
InputStream en_is = null;
InputStream fr_is = null;
try {
this.en_prop = new Properties();
this.fr_prop = new Properties();
en_is = this.getClass().getResourceAsStream(en_path);
fr_is = this.getClass().getResourceAsStream(fr_path);
Reader reader = new InputStreamReader(fr_is, "UTF-8");
en_prop.load(en_is);
fr_prop.load(reader);
reader.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
By introducing the reader and using that, it has cleared up French character corruption.
I should mention that I changed every file property I could find over to UTF-8 before I did the above changes and got it working. This site gives you the changes I made. This was a nice page that helped me confirm the encodings.

Issue with loading class from jar file represented as byte array

I'm trying to create an instance of a class from jar file loaded on a byte array.
I'm receiving two args:
1. byte[] which represents jar file with required class
2. Qualified class name
When I'm testing it locally it works as expected, but when I upload exactly the same jar file with the same qualified class name remotely (using web application implemented with Spring MVC for back and AngularJS for front end deployed in Tomcat server) It can't find the required class:
java.lang.ClassNotFoundException
When I was debugging, it turned out, that classloader is properly invoked but no one class is loaded from jar.
I would be grateful if anyone can tell what can be the reason of that difference or how can I implement this functionality in other ways.
A method which loads class and returns an instance of it:
public static <T> T getInstanceOfLoadedClass(byte[] jarFileBytes, String qualifiedClassName) throws ClassFromJarInstantiationException {
LOGGER.info("Getting instance of class from loaded jar file. Class name: " + qualifiedClassName);
try {
return (T) Class.forName(qualifiedClassName, true, new ByteClassLoader(jarFileBytes)).newInstance();
} catch (InstantiationException | IllegalAccessException | IOException | ClassNotFoundException | NoSuchFieldException e) {
LOGGER.error("Exception was thrown while reading jar file for " + qualifiedClassName + "class.", e);
throw new ClassFromJarInstantiationException(e);
}
}
Custom ByteClassLoader:
public class ByteClassLoader extends ClassLoader {
private static final Logger LOGGER = Logger.getLogger(ByteClassLoader.class);
private final byte[] jarBytes;
private final Set<String> names;
public ByteClassLoader(byte[] jarBytes) throws IOException {
this.jarBytes = jarBytes;
this.names = loadNames(jarBytes);
}
private Set<String> loadNames(byte[] jarBytes) throws IOException {
Set<String> set = new HashSet<>();
try (ZipInputStream jis = new ZipInputStream(new ByteArrayInputStream(jarBytes))) {
ZipEntry entry;
while ((entry = jis.getNextEntry()) != null) {
set.add(entry.getName());
}
}
return Collections.unmodifiableSet(set);
}
#Override
public InputStream getResourceAsStream(String resourceName) {
if (!names.contains(resourceName)) {
return null;
}
boolean found = false;
ZipInputStream zipInputStream = null;
try {
zipInputStream = new ZipInputStream(new ByteArrayInputStream(jarBytes));
ZipEntry entry;
while ((entry = zipInputStream.getNextEntry()) != null) {
if (entry.getName().equals(resourceName)) {
found = true;
return zipInputStream;
}
}
} catch (IOException e) {
LOGGER.error("ByteClassLoader threw exception while reading jar byte stream for resource: "+resourceName, e);
e.printStackTrace();
} finally {
if (zipInputStream != null && !found) {
try {
zipInputStream.close();
} catch (IOException e) {
LOGGER.error("ByteClassLoader threw exception while closing jar byte stream for resource: "+resourceName, e);
e.printStackTrace();
}
}
}
return null;
} }

The problem was that the class required to be loaded was in a range of classloader while it was tested.
Hope it helps someone in solving this problem because it is really easy to miss.

Getting Properties Object from config.properties file after deployment

I have a config file containing server information such as FTP URL's and their credentials. I am trying to, on deployment of my web app, reference the config.properties file to assign the stored values to local variables but for whatever reason cannot find the file.
I have a getConfigProperties class:
public class getConfigProperties {
public Properties getConfig(String fileName) {
// load config file
Properties prop = new Properties();
InputStream input = null;
try {
// grab config file from destination
input = getConfigProperties.class.getClass().getResourceAsStream(
fileName);
// check if input is null
if (input == null) {
System.out.println("Sorry, unable to find "
+ "config.properties");
return null;
}
// load content
prop.load(input);
// start to declare variables
// Prod vars
System.out.println(prop.getProperty("prismUrlProd"));
System.out.println(prop.getProperty("prismUserProd"));
System.out.println(prop.getProperty("prismPassProd"));
System.out.println(prop.getProperty("cardUrlProd"));
System.out.println(prop.getProperty("cardUserProd"));
System.out.println(prop.getProperty("cardPassProd"));
System.out.println(prop.getProperty("pwcProd"));
System.out.println(prop.getProperty("esdSignInProd"));
System.out.println(prop.getProperty("emailProd"));
// used to catch possible errors
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (input != null) {
try {
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return prop;
}
public static void main(String[] args) {
getConfigProperties a = new getConfigProperties();
a.getConfig("/config/config.properties");
}
}
And I use this in another class to assign the variables. Inside my method, I set a Properties object to what is returned from getConfig(String filename):
public static void initialize() {
// load config file
getConfigProperties config = new getConfigProperties();
Properties prop = config.getConfig("/config/config.properties");
}
It's explained in properties file in web app that on deplyoment, our location of the config.properties changes, but when trying "/WEB-INF/classes/config/config.properties", I can't find the file. Using the main in my getConfigProperties class, I am able to find config.properties no problem and reference the text in my config file by printing it to console. Any possible suggestions as to where this file may be on deployment? Do I have to reference it a certain way? Any help would much be appreciated.

I got this to work by putting config.properties in my src folder and referencing it by "config.properties".

A properties file I created in the 1st run gets blanked in the 2nd run

Okay, I'm trying to create a custom client for Minecraft (don't worry, my question has nothing to do with Minecraft in particular), and I added an abstract class to manage a configuration file using Java's built-in Properties system. I have a method that loads a properties file or creates it if it doesn't already exist. This method is called at the beginning of all my other methods (although it only does anything the first time its called).
The properties file gets created just fine when I run Minecraft the first time, but somehow when I run it the second time, the file gets blanked out. I'm not sure where or why or how I'm wiping the file clean, can someone please help me? Here's my code; the offending method is loadConfig():
package net.minecraft.src;
import java.util.*;
import java.util.regex.*;
import java.io.*;
/**
* Class for managing my custom client's properties
*
* #author oxguy3
*/
public abstract class OxProps
{
public static boolean configloaded = false;
private static Properties props = new Properties();
private static String[] usernames;
public static void loadConfig() {
System.out.println("loadConfig() called");
if (!configloaded) {
System.out.println("loading config for the first time");
File cfile = new File("oxconfig.properties");
boolean configisnew;
if (!cfile.exists()) {
System.out.println("cfile failed exists(), creating blank file");
try {
configisnew = cfile.createNewFile();
} catch (IOException e) {
e.printStackTrace();
configisnew=true;
}
} else {
System.out.println("cfile passed exists(), proceding");
configisnew=false;
}
FileInputStream cin = null;
FileOutputStream cout = null;
try {
cin = new FileInputStream(cfile);
cout = new FileOutputStream(cfile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
if (!configisnew) { //if the config already existed
System.out.println("config already existed");
try {
props.load(cin);
} catch (IOException e) {
e.printStackTrace();
}
} else { //if it doesn't exist, and therefore needs to be created
System.out.println("creating new config");
props.setProperty("names", "oxguy3, Player");
props.setProperty("cloak_url", "http://s3.amazonaws.com/MinecraftCloaks/akronman1.png");
try {
props.store(cout, "OXGUY3'S CUSTOM CLIENT\n\ncloak_url is the URL to get custom cloaks from\nnames are the usernames to give cloaks to\n");
cout.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
String names = props.getProperty("names");
System.out.println("names: "+names);
try {
usernames = Pattern.compile(", ").split(names);
} catch (NullPointerException npe) {
npe.printStackTrace();
}
System.out.println("usernames: "+Arrays.toString(usernames));
configloaded=true;
}
}
public static boolean checkUsername(String username) {
loadConfig();
System.out.println("Checking username...");
for (int i=0; i<usernames.length; i++) {
System.out.println("comparing "+username+" with config value "+usernames[i]);
if (username.startsWith(usernames[i])){
System.out.println("we got a match!");
return true;
}
}
System.out.println("no match found");
return false;
}
public static String getCloakUrl() {
loadConfig();
return props.getProperty("cloak_url", "http://s3.amazonaws.com/MinecraftCloaks/akronman1.png");
}
}
If it's too hard to read here, it's also on Pastebin: http://pastebin.com/9UscXWap
Thanks!

You are unconditionally creating new FileOutputStream(cfile). This will overwrite the existing file with an empty one. You should only invoke the FileOutputStream constructor when writing a new config file.
if (configloaded)
return;
File cfile = new File("oxconfig.properties");
try {
if (cfile.createNewFile()) {
try {
FileOutputStream cout = new FileOutputStream(cfile);
props.setProperty("names", "oxguy3, Player");
props.setProperty("cloak_url", "http://...");
...
cout.flush();
} finally {
cout.close();
}
} else {
FileInputStream cin = new FileInputStream(cfile);
try {
props.load(cin);
} finally {
cin.close();
}
}
configloaded=true;
} catch(IOException ex) {
e.printStackTrace();
}