In my program I need to read in a config file. Unfortunately every attempt to read it ends without getting the data correctly. Debugging showed that the inputReader always is null. The config file is in my resources folder. Can’t it be found like that or why is the inputReader only null?
private String result;
private final Properties property = new Properties();
public String getString(ConfigType type) {
InputStream inputReader = null;
try {
inputReader = getClass().getResourceAsStream("/resources/config");
if (inputReader != null) {
property.load(inputReader);
inputReader.close();
result = property.getProperty(type.getValue());
}
} catch (IOException exception){
}
}
AFAIK, the reason behind null is invalid directory path.
don't use / in the directory "**/**resources/yourfile" if you don't have any root or parent directory of resource folder.
You don't need to assign null in your inputStream.
InputStream inputStream = getClass().getResourceAsStream("resources/config.properties");
Should work.
I am using following java code in my application:
protected String encryptContact(Long contactId) {
if (contactId != null) {
EncryptionFactoryBean enbe = new EncryptionFactoryBean(String.valueOf(contactId), "/etc/test/encrypt.properties");
try {
enbe.SetProperties();
return (String) enbe.getObject();
} catch (Exception e) {
return null;
}
}
return null;
}
In EncryptionFactoryBean.java
public void setProperties()
throws Exception {
Assert.notNull(textToEncrypt, "encryption text cannot be null");
encryptionProperties = loadFile(encryptionFile);
super.setProperties();
}
protected Properties loadFile(String filename)
throws IOException {
Properties properties = null;
if (StringUtils.hasText(filename)) {
File file = new File(filename);
if (file.exists()) {
FileInputStream fi = new FileInputStream(file);
properties = new Properties();
properties.load(fi);
fi.close();
}
}
return properties;
}
On running the application, I am getting following error -
javax.servlet.ServletException: java.io.FileNotFoundException:
/etc/test/encrypt.properties (Too many open files)
It is not possible to increase the file limit in the application. Is there any way to fix this issue? Is it possible to close the file handler through finally ?
Console log error :
[org.apache.tomcat.util.net.JIoEndpoint] Socket accept failed java.net.SocketException: Too many open files
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:404)
at java.net.ServerSocket.implAccept(ServerSocket.java:545)
at java.net.ServerSocket.accept(ServerSocket.java:513)
at org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:61)
at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:352)
at java.lang.Thread.run(Thread.java:745)
Most probably during the process of new EncryptionFactoryBean(String, String) you have something similar to
Properties props = new Properties();
Reader inStream = new FileReader("/etc/test/encrypt.properties");
props.load(inStream);
As the Javdoc of Properties.load(Reader) / Properties.load(InputStream) mention
The specified stream remains open after this method returns.
You need to close the stream yourself. For example like:
Properties props = new Properties();
try (Reader inStream = new FileReader("/etc/test/encrypt.properties")) {
props.load(inStream);
}
I have a configuration file from which I have to read some properties. This configuration file exists in diferent locations but has the same name. I am able to read a configuration file, but only one from my project. I used the following code:
Properties prop = new Properties();
String propFileName = "config.properties";
InputStream inputStream = getClass().getClassLoader().getResourceAsStream(propFileName);
try {
prop.load(inputStream);
} catch (IOException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
if (inputStream == null) {
try {
throw new FileNotFoundException("property file '" + propFileName + "' not found in the classpath");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I have to open the config file using the full path so instead of propFileName="config.properties" to insert the absolute path to the config file. The config file can't be opened if I use the absolute path.
How can this be done ?
InputStream inputStream = new FileInputStream("path");
will open a file with an absolute path.
Note: This will only work for a file, it will not work for anything included in a plugin jar.
You can use FileInputStream for locating config file outside of your project path.
Properties prop = new Properties();
InputStream input = new FileInputStream("/home/ubuntu/Desktop/sample.properties");
prop.load(input);
System.out.println(prop.get("test"));
When specifying path we need give file name with extension.
I have a config.properties file at the root of my blackberry project (same place as Blackberry_App_Descriptor.xml file), and I try to access the file to read and write into it.
See below my class:
public class Configuration {
private String file;
private String fileName;
public Configuration(String pathToFile) {
this.fileName = pathToFile;
try {
// Try to load the file and read it
System.out.println("---------- Start to read the file");
file = readFile(fileName);
System.out.println("---------- Property file:");
System.out.println(file);
} catch (Exception e) {
System.out.println("---------- Error reading file");
System.out.println(e.getMessage());
}
}
/**
* Read a file and return it in a String
* #param fName
* #return
*/
private String readFile(String fName) {
String properties = null;
try {
System.out.println("---------- Opening the file");
//to actually retrieve the resource prefix the name of the file with a "/"
InputStream is = this.getClass().getResourceAsStream(fName);
//we now have an input stream. Create a reader and read out
//each character in the stream.
System.out.println("---------- Input stream");
InputStreamReader isr = new InputStreamReader(is);
char c;
System.out.println("---------- Append string now");
while ((c = (char)isr.read()) != -1) {
properties += c;
}
} catch (Exception e) {
}
return properties;
}
}
I call my class constructor like this:
Configuration config = new Configuration("/config.properties");
So in my class, "file" should have all the content of the config.properties file, and the fileName should have this value "/config.properties".
But the "name" is null because the file cannot be found...
I know this is the path of the file which should be different, but I don't know what i can change... The class is in the package com.mycompany.blackberry.utils
Thank you!
I think you need to put the config.properties file into a source folder when you build the project, you can create a "resources" folder as a src folder and put the config file in it, than you can get the file in the app
Try putting the file in the same package as the class?
Class clazz = Class.forName("Configuration");
InputStream is = addFile.getResourceAsStream(fName);
I have a list of key/value pairs of configuration values I want to store as Java property files, and later load and iterate through.
Questions:
Do I need to store the file in the same package as the class which will load them, or is there any specific location where it should be placed?
Does the file need to end in any specific extension or is .txt OK?
How can I load the file in the code
And how can I iterate through the values inside?
You can pass an InputStream to the Property, so your file can pretty much be anywhere, and called anything.
Properties properties = new Properties();
try {
properties.load(new FileInputStream("path/filename"));
} catch (IOException e) {
...
}
Iterate as:
for(String key : properties.stringPropertyNames()) {
String value = properties.getProperty(key);
System.out.println(key + " => " + value);
}
You can store the file anywhere you like. If you want to keep it in your jar file, you'll want to use Class.getResourceAsStream() or ClassLoader.getResourceAsStream() to access it. If it's on the file system it's slightly easier.
Any extension is fine, although .properties is more common in my experience
Load the file using Properties.load, passing in an InputStream or a StreamReader if you're using Java 6. (If you are using Java 6, I'd probably use UTF-8 and a Reader instead of the default ISO-8859-1 encoding for a stream.)
Iterate through it as you'd iterate through a normal Hashtable (which Properties derives from), e.g. using keySet(). Alternatively, you can use the enumeration returned by propertyNames().
If you put the properties file in the same package as class Foo, you can easily load it with
new Properties().load(Foo.class.getResourceAsStream("file.properties"))
Given that Properties extends Hashtable you can iterate over the values in the same manner as you would in a Hashtable.
If you use the *.properties extension you can get editor support, e.g. Eclipse has a properties file editor.
There are many ways to create and read properties files:
Store the file in the same package.
Recommend .properties extension however you can choose your own.
Use theses classes located at java.util package => Properties, ListResourceBundle, ResourceBundle classes.
To read properties, use iterator or enumerator or direct methods of Properties or java.lang.System class.
ResourceBundle class:
ResourceBundle rb = ResourceBundle.getBundle("prop"); // prop.properties
System.out.println(rb.getString("key"));
Properties class:
Properties ps = new Properties();
ps.Load(new java.io.FileInputStream("my.properties"));
This load the properties file:
Properties prop = new Properties();
InputStream stream = ...; //the stream to the file
try {
prop.load(stream);
} finally {
stream.close();
}
I use to put the .properties file in a directory where I have all the configuration files, I do not put it together with the class that accesses it, but there are no restrictions here.
For the name... I use .properties for verbosity sake, I don't think you should name it .properties if you don't want.
Properties has become legacy. Preferences class is preferred to Properties.
A node in a hierarchical collection of preference data. This class allows applications to store and retrieve user and system preference and configuration data. This data is stored persistently in an implementation-dependent backing store. Typical implementations include flat files, OS-specific registries, directory servers and SQL databases. The user of this class needn't be concerned with details of the backing store.
Unlike properties which are String based key-value pairs, The Preferences class has several methods used to get and put primitive data in the Preferences data store. We can use only the following types of data:
String
boolean
double
float
int
long
byte array
To load the the properties file, either you can provide absolute path Or use getResourceAsStream() if the properties file is present in your classpath.
package com.mypack.test;
import java.io.*;
import java.util.*;
import java.util.prefs.Preferences;
public class PreferencesExample {
public static void main(String args[]) throws FileNotFoundException {
Preferences ps = Preferences.userNodeForPackage(PreferencesExample.class);
// Load file object
File fileObj = new File("d:\\data.xml");
try {
FileInputStream fis = new FileInputStream(fileObj);
ps.importPreferences(fis);
System.out.println("Prefereces:"+ps);
System.out.println("Get property1:"+ps.getInt("property1",10));
} catch (Exception err) {
err.printStackTrace();
}
}
}
xml file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE preferences SYSTEM 'http://java.sun.com/dtd/preferences.dtd'>
<preferences EXTERNAL_XML_VERSION="1.0">
<root type="user">
<map />
<node name="com">
<map />
<node name="mypack">
<map />
<node name="test">
<map>
<entry key="property1" value="80" />
<entry key="property2" value="Red" />
</map>
</node>
</node>
</node>
</root>
</preferences>
Have a look at this article on internals of preferences store
Example:
Properties pro = new Properties();
FileInputStream in = new FileInputStream("D:/prop/prop.properties");
pro.load(in);
String temp1[];
String temp2[];
// getting values from property file
String username = pro.getProperty("usernamev3");//key value in prop file
String password = pro.getProperty("passwordv3");//eg. username="zub"
String delimiter = ","; //password="abc"
temp1=username.split(delimiter);
temp2=password.split(delimiter);
In order:
You can store the file pretty much anywhere.
no extension is necessary.
Montecristo has illustrated how to load this. That should work fine.
propertyNames() gives you an enumeration to iterate through.
By default, Java opens it in the working directory of your application (this behavior actually depends on the OS used). To load a file, do:
Properties props = new java.util.Properties();
FileInputStream fis new FileInputStream("myfile.txt");
props.load(fis)
As such, any file extension can be used for property file. Additionally, the file can also be stored anywhere, as long as you can use a FileInputStream.
On a related note if you use a modern framework, the framework may provide additionnal ways of opening a property file. For example, Spring provide a ClassPathResource to load a property file using a package name from inside a JAR file.
As for iterating through the properties, once the properties are loaded they are stored in the java.util.Properties object, which offer the propertyNames() method.
Reading a properties file and loading its contents to Properties
String filename = "sample.properties";
Properties properties = new Properties();
input = this.getClass().getClassLoader().getResourceAsStream(filename);
properties.load(input);
The following is the efficient way to iterate over a Properties
for (Entry<Object, Object> entry : properties.entrySet()) {
System.out.println(entry.getKey() + " => " + entry.getValue());
}
In Java 8 to get all your properties
public static Map<String, String> readPropertiesFile(String location) throws Exception {
Map<String, String> properties = new HashMap<>();
Properties props = new Properties();
props.load(new FileInputStream(new File(location)));
props.forEach((key, value) -> {
properties.put(key.toString(), value.toString());
});
return properties;
}
1) It is good to have your property file in classpath but you can place it anywhere in project.
Below is how you load property file from classpath and read all properties.
Properties prop = new Properties();
InputStream input = null;
try {
String filename = "path to property file";
input = getClass().getClassLoader().getResourceAsStream(filename);
if (input == null) {
System.out.println("Sorry, unable to find " + filename);
return;
}
prop.load(input);
Enumeration<?> e = prop.propertyNames();
while (e.hasMoreElements()) {
String key = (String) e.nextElement();
String value = prop.getProperty(key);
System.out.println("Key : " + key + ", Value : " + value);
}
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (input != null) {
try {
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
2) Property files have the extension as .properties
Here is another way to iterate over the properties:
Enumeration eProps = properties.propertyNames();
while (eProps.hasMoreElements()) {
String key = (String) eProps.nextElement();
String value = properties.getProperty(key);
System.out.println(key + " => " + value);
}
I have written on this property framework for the last year.
It will provide of multiple ways to load properties, and have them strongly typed as well.
Have a look at http://sourceforge.net/projects/jhpropertiestyp/
JHPropertiesTyped will give the developer strongly typed properties.
Easy to integrate in existing projects.
Handled by a large series for property types.
Gives the ability to one-line initialize properties via property IO implementations.
Gives the developer the ability to create own property types and property io's.
Web demo is also available, screenshots shown above.
Also have a standard implementation for a web front end to manage properties, if you choose to use it.
Complete documentation, tutorial, javadoc, faq etc is a available on the project webpage.
Here ready static class
import java.io.*;
import java.util.Properties;
public class Settings {
public static String Get(String name,String defVal){
File configFile = new File(Variables.SETTINGS_FILE);
try {
FileReader reader = new FileReader(configFile);
Properties props = new Properties();
props.load(reader);
reader.close();
return props.getProperty(name);
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
return defVal;
} catch (IOException ex) {
// I/O error
logger.error(ex);
return defVal;
} catch (Exception ex){
logger.error(ex);
return defVal;
}
}
public static Integer Get(String name,Integer defVal){
File configFile = new File(Variables.SETTINGS_FILE);
try {
FileReader reader = new FileReader(configFile);
Properties props = new Properties();
props.load(reader);
reader.close();
return Integer.valueOf(props.getProperty(name));
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
return defVal;
} catch (IOException ex) {
// I/O error
logger.error(ex);
return defVal;
} catch (Exception ex){
logger.error(ex);
return defVal;
}
}
public static Boolean Get(String name,Boolean defVal){
File configFile = new File(Variables.SETTINGS_FILE);
try {
FileReader reader = new FileReader(configFile);
Properties props = new Properties();
props.load(reader);
reader.close();
return Boolean.valueOf(props.getProperty(name));
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
return defVal;
} catch (IOException ex) {
// I/O error
logger.error(ex);
return defVal;
} catch (Exception ex){
logger.error(ex);
return defVal;
}
}
public static void Set(String name, String value){
File configFile = new File(Variables.SETTINGS_FILE);
try {
Properties props = new Properties();
FileReader reader = new FileReader(configFile);
props.load(reader);
props.setProperty(name, value.toString());
FileWriter writer = new FileWriter(configFile);
props.store(writer, Variables.SETTINGS_COMMENT);
writer.close();
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
} catch (IOException ex) {
// I/O error
logger.error(ex);
} catch (Exception ex){
logger.error(ex);
}
}
public static void Set(String name, Integer value){
File configFile = new File(Variables.SETTINGS_FILE);
try {
Properties props = new Properties();
FileReader reader = new FileReader(configFile);
props.load(reader);
props.setProperty(name, value.toString());
FileWriter writer = new FileWriter(configFile);
props.store(writer,Variables.SETTINGS_COMMENT);
writer.close();
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
} catch (IOException ex) {
// I/O error
logger.error(ex);
} catch (Exception ex){
logger.error(ex);
}
}
public static void Set(String name, Boolean value){
File configFile = new File(Variables.SETTINGS_FILE);
try {
Properties props = new Properties();
FileReader reader = new FileReader(configFile);
props.load(reader);
props.setProperty(name, value.toString());
FileWriter writer = new FileWriter(configFile);
props.store(writer,Variables.SETTINGS_COMMENT);
writer.close();
} catch (FileNotFoundException ex) {
// file does not exist
logger.error(ex);
} catch (IOException ex) {
// I/O error
logger.error(ex);
} catch (Exception ex){
logger.error(ex);
}
}
}
Here sample:
Settings.Set("valueName1","value");
String val1=Settings.Get("valueName1","value");
Settings.Set("valueName2",true);
Boolean val2=Settings.Get("valueName2",true);
Settings.Set("valueName3",100);
Integer val3=Settings.Get("valueName3",100);
You can load the property file suing the following way:
InputStream is = new Test().getClass().getClassLoader().getResourceAsStream("app.properties");
Properties props = new Properties();
props.load(is);
And then you can iterate over the map using a lambda expression like:
props.stringPropertyNames().forEach(key -> {
System.out.println("Key is :"+key + " and Value is :"+props.getProperty(key));
});
in my opinion other ways are deprecated when we can do it very simple as below:
#PropertySource("classpath:application.properties")
public class SomeClass{
#Autowired
private Environment env;
public void readProperty() {
env.getProperty("language");
}
}
it is so simple but i think that's the best way!!
Enjoy