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properties.getProperty(key) method returns null value

I am load the properties file and get the value from that file but when i using "Properties" class and getProperty(key) method, it was return null value.
code:
public class LoadPropertiesFile {
public static String getProperty (String key, String filePath) {
Properties properties = new Properties();
InputStream inputStream = null;
String value = null;
try {
String appHome = ConfigUtil.getApplicationHome() + filePath;
inputStream = new FileInputStream(appHome);
//load a properties file
properties.load(inputStream);
//get the property value
System.out.println(properties.getProperty("7")); //print **Unlock**
System.err.println(key); //print **7**
System.out.println(value); //print **null**
value = properties.getProperty(key);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch(IOException e) {
e.printStackTrace();
}
}
}
return value;
}
}
Output:
Unlock
7
null
Property File:
2=Interactive
3=Network
4=Batch
5=Service
7=Unlock
8=Network Cleartext
10=Remote Desktop
11=Logon with cached credentials
call method:
logonType = new LoadPropertiesFile().getProperty("7", "path");
When i call that method it will return null value only. please help me guys.

You are initalizing value with null.
String value = null;
And you assign it after printing it:
System.out.println(value);
value = properties.getProperty(key);
Output: null
So value can only be null when you print it, as you never change its value until System.out.println(value);.
Just switch those two statements:
value = properties.getProperty(key);
System.out.println(value);
Output: unlock
Edit
properties.getProperty(key) may return null too, but only if there is no such key in its table, otherwise it will return the assigned value, in your example unlock.
See the API Documentation on this for more details:
public String getProperty(String key)
Searches for the property with the specified key in this property list. If the key is not found in
this property list, the default property list, and its defaults,
recursively, are then checked. The method returns null if the property
is not found.
http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html#getProperty(java.lang.String)

System.out.println(value); //print **null**
value = properties.getProperty(key);
Switch these two lines and initialize value before printing it:
value = properties.getProperty(key);
System.out.println(value); //print Unlock

struts how to set specific name to uploaded file

i want to give specific name to the uploaded file in my destination folder.. this is my action file code.. here i want to give name like CPIC_1.jpg,CPIC_2.jpg,CPIC_3.jpg,CPIC_4.jpg etc but every time it is assigning name : CPIC_1.jpg.. so how i declare variable ext so that through out it will be distinct..
CommercialFileBean b = (CommercialFileBean) form;
FormFile f = b.getF();
String s = request.getParameter("action");
HttpSession session = request.getSession(false);
String n = (String) session.getAttribute("str");
String email = session.getAttribute("uname").toString();
String status = (String) session.getAttribute("status");
String type = request.getParameter("type");
String pid;
long ext=0;
int id;
if (s.equalsIgnoreCase("finish")) {
return mapping.findForward(next);
} else { /// first else
String a = getServlet().getServletContext().getRealPath("/");
File file = new File(a + "uploaded/CPIC_"+ ++ext+".jpg");
if (!file.exists()) {
FileOutputStream out = new FileOutputStream(file);
out.write(f.getFileData());
out.close();
}
try {
if (n.equalsIgnoreCase("rent")) {
Session sess = UtilClass.createSession();
Transaction tx = sess.beginTransaction();
if (status.equalsIgnoreCase("new")) {
String sql1 = "select MAX(id) from Rentcommercialrecord where loginid=:email";
Query q1 = sess.createQuery(sql1);
q1.setParameter("email", email);
// JOptionPane.showMessageDialog(null, "max id is :");
List<Rentcommercialrecord> l = q1.list();
Rentcommercialrecord rc = l.get(l.size()-1);
id = rc.getId();
} else {
pid = (String) session.getAttribute("id");
id = Integer.parseInt(pid);
}
JOptionPane.showMessageDialog(null, " latest id is :" + id);
if (type.equalsIgnoreCase("frontpic")) {
try {
String file1 = f.getFileName();
JOptionPane.showMessageDialog(null, "file name is : "+file1);
Rentcommercialrecord rc1 = (Rentcommercialrecord) sess.get(Rentcommercialrecord.class, id);
rc1.setImg1("CPIC_" +ext+".jpg");
sess.update(rc1);
// JOptionPane.showMessageDialog(null, "img1");
} // img1 try ends
catch (Exception e) {
JOptionPane.showMessageDialog(null, "Second error is : " + e.getMessage());
}
} // fontpic if ends
else {
try {
String file1 = f.getFileName();
JOptionPane.showMessageDialog(null, "file name is : "+file1);
Rentcommercialrecord rc1 = (Rentcommercialrecord) sess.get(Rentcommercialrecord.class, id);
rc1.setImg2("CPIC_" +ext+".jpg");
sess.update(rc1);
// JOptionPane.showMessageDialog(null, "img2");
} // img2 try ends
catch (Exception e) {
JOptionPane.showMessageDialog(null, "Second error is : " + e.getMessage());
}
} // else img2 ends
// l.size if ends
tx.commit();
}

Make your variable ext as static.
static long ext = 0;
This will make the variable common to all instances.
Note : You need to store this value somewhere in db / file during restart and get it during application startup to make it consistent irrespective of restart of your application

You can make your ext variable static
Note: The scope of your static variable is for the current class Loader. ie, if it is a diff class loader is used , this will change.
other option is store the ext value in session and every time you upload a new image file, get this value from session and use it. And you need to put the new value back into session as well. This approach will work for per user. ie if your application is having diff users, for diff users it will have diff value based on session

You can use a static variable, but it won't be consistent through application restarts.
I would change approach and would read filenames, then extracting the numbers from their names, getting the highest, incrementing it and then writing a new file.
Use Apache Commons to avoid reinventing the wheel.
Kickoff example:
String path = getServlet().getServletContext().getRealPath("/") + "uploaded/";
String partialName = "CPIC_";
int markerLength = partialName.length();
int maxValue = 0;
// Find all files, if any, with name starting with "CPIC_" in the desired folder
List<File> files = FileUtils.listFiles(new File(path),
new PrefixFileFilter(partialName),
null);
if (!files.isEmpty()){
for (File file : files) {
// Strip marker and extension
int num = Integer.parseInt(
file.getName().substring(markerLength,
file.getName().indexOf("."))
);
// compare the number, if greater, set as new max value
if (num > maxValue) {
maxValue = num;
}
}
}
String newFile = partialName + ++maxValue + ".jpg";
System.out.println("Next file name would be : " + newFile);

Why the code doesn't change .properties file

I have the following code which must add new values to the existing properties in the .properties file of, if the property doesn't exist - create it.
public String saveProperties(ArrayList<Property> properties, String customerId){
final String userPropFieldName = "users." + customerId + ".rules";
try{
PropertiesConfiguration props = new PropertiesConfiguration("/home/mikhail/bzrrep/DLP/DLPServer/src/main/resources/rules.properties");
for (Property property: properties){
String fieldName = "rules." + property.getName() + "." + property.getType();
String[] values = (property.getValue()).split("\\,");
for (String word: values){
System.out.print(word + " ");
}
if (util.exist(fieldName, props)){
props.setProperty(fieldName, values);
} else {
props.addProperty(fieldName, values);
}
String[] userProperties = props.getStringArray(userPropFieldName);
if (property.getAccepted()){
userProperties = util.addNewValue(userProperties, fieldName);
} else {
userProperties = util.removeValue(userProperties, fieldName);
}
props.setProperty(userPropFieldName, userProperties);
}
}catch (ConfigurationException e){
e.printStackTrace();
}
return "Saved";
}
I run it with the debugger and all values right, I mean, there are the proper name of the property and the proper values in the array, so, seen that it came up to the adding or setting new value, but finally I didn't see any changes in the property file.

Save your modified properties to file
props.save();
Read more: http://commons.apache.org/proper/commons-configuration/userguide/howto_properties.html#Saving
BTW, Saving properties directly to source code (src/main/resources/rules.properties) is usually bad idea.

ComboBox adds all the values together as one value

I'm making an application at the moment and now I need to fill a comboBox with all the values that I get from another class in an arrayList type.
This is the code that I use to fill my combobox:
public void setComboBox(){
MessageConsole mc = new MessageConsole(textArea);
//The redirectOut will redirect the text from the System.out.prtnln to the text area.
mc.redirectOut();
List<String> arrayList = new ArrayList<String>();
if(gf.loadCombo("config") != null){
arrayList.addAll(gf.loadCombo("config"));
for (int i = 0; i < arrayList.size(); i++) {
String s = arrayList.get(i);
configName.removeItem(s);
configName.addItem(s);
}
}
}
This is the code from the other class:
public Collection<String> loadCombo(String property) {
//Check if the property file is present in the given directory.
if(cf.checkProperty()==true){
//Check is there are any properties saved in the property file.
if(cf.getProperty() != null){
Properties prop = new Properties();
FileInputStream fis;
try {
fis = new FileInputStream("config.properties");
prop.load(fis);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//Check if the properties match with the entered configuration.
List<String> arrayList = new ArrayList<String>();
arrayList.addAll(cf.getProperty());
Collection<String> propertyList = new ArrayList<String>();
for (int i = 0; i < arrayList.size(); i++) {
String s = arrayList.get(i);
if(s.startsWith(property)){
System.out.println("This value has been added to the arrayList from the other class: "+s);
propertyList.add(cf.getPropertyValue(s));
}
}
return propertyList;
}
//The system prints a message of the missing properties.
else{
System.out.println("You need to save a configuration first.");
}
}
//The system prints a message of the missing property file.
else{
System.out.println("The property file is either missing or could not be found. in de Load class");
}
return null;
}
Following is a screenshot of the result:
As you can see all the values are added as 1 long String"[3, 2, 1]" in the comboBox. Could anyone tell me why this happens?
Thanks in advance,
Lordarnoud
P.S. I hope this is the correct way to ask my question and I hope my question is clear enough for everyone to understand.

At a first look it appears the problem could be one of two things:
The value "[3 2 1]" is returned from the loadCombo method. More specifically from the cf.getProperty(). It is not clear from the context provided what cf is.
The value "[3 2 1]" was added to your combobox at some other point in you code. If this might be case, try using configName.removeAllItems() instead of removing then adding each item in your collection.
Additionally in your loadCombo method you load the config.properties file into a Properties object and then do nothing with it. It seems your intentions were to load the config properties from that file instead of the cf object.

Java Properties object to String

I have a Java Properties object that I load from an in-memory String, that was previously loaded into memory from the actual .properties file like this:
this.propertyFilesCache.put(file, FileUtils.fileToString(propFile));
The util fileToString actually reads in the text from the file and the rest of the code stores it in a HashMap called propertyFilesCache. Later, I read the file text from the HashMap as a String and reload it into a Java Properties object like so:
String propFileStr = this.propertyFilesCache.get(fileName);
Properties tempProps = new Properties();
try {
tempProps.load(new ByteArrayInputStream(propFileStr.getBytes()));
} catch (Exception e) {
log.debug(e.getMessage());
}
tempProps.setProperty(prop, propVal);
At this point, I've replaced my property in my in-memory property file and I want to get the text from the Properties object as if I was reading a File object like I did up above. Is there a simple way to do this or am I going to have to iterate over the properties and create the String manually?

public static String getPropertyAsString(Properties prop) {
StringWriter writer = new StringWriter();
prop.list(new PrintWriter(writer));
return writer.getBuffer().toString();
}

There seems to be a problem with #Isiu answer. After that code Properties are truncated, like there is some limit to string length. Proper way is to use code like this:
public static String getPropertyAsString(Properties prop) {
StringWriter writer = new StringWriter();
try {
prop.store(writer, "");
} catch (IOException e) {
...
}
return writer.getBuffer().toString();
}

It's not directly related to your question but if you just want to print out properties for debugging you can do something like this
properties.list(System.out);

If you are using Java 8 or above, here is a single statement solution with the possibility to control the format by yourself:
String properties = System.getProperties().entrySet()
.stream()
.map(e -> e.getKey() + ":" + e.getValue())
.collect(Collectors.joining(", "));

I don't completely understand what you're trying to do, but you can use the Properties class' store(OutputStream out, String comments) method. From the javadoc:
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.

You can do as below also:
Properties p = System.getProperties();
Enumeration keys = p.keys();
while (keys.hasMoreElements()) {
String key = (String)keys.nextElement();
String value = (String)p.get(key);
System.out.println(key + ": " + value);
}

Another function to print all the values of a field is :
public static <T>void printFieldValue(T obj)
{
System.out.printf("###" + obj.getClass().getName() + "###");
for (java.lang.reflect.Field field : obj.getClass().getDeclaredFields()) {
field.setAccessible(true);
String name = field.getName();
Object value = null;
try{
value = field.get(obj);
}catch(Throwable e){}
System.out.printf("#Field name: %s\t=> %s%n", name, value);
}
}

Using the list method is incorrect because it should be used only for debugging purposes
Prints this property list out to the specified output stream.
This method is useful for debugging.
It doesn't escape keys which contains special characters, like = or :.
The store method should be used, but it inserts a comment and timestamp. The following code removes these additional lines and returns a text with normalized new lines.
Java
public static String propertiesToString(Properties properties) throws IOException {
if (properties == null) {
return null;
}
if (properties.isEmpty()) {
return "";
}
StringWriter writer = new StringWriter();
properties.store(writer, null);
String text = normalizeNewLines(writer.toString());
List<String> lines = new ArrayList<>(Arrays.asList(text.split("\n")));
lines.remove(0);
return lines.stream().collect(Collectors.joining("\n"));
}
private static String normalizeNewLines(String text) {
return text.replace("\r\n", "\n").replace("\r", "\n");
}
Groovy
static String propertiesToString(Properties properties) {
if (properties.is(null)) {
return null
}
if (properties.isEmpty()) {
return ''
}
def writer = new StringWriter()
properties.store(writer, null)
def lines = normalizeNewLines(writer).split('\n') as List
lines.remove(0)
return lines.join('\n')
}
private static String normalizeNewLines(String text) {
return text.replace('\r\n', '\n').replace('\r', '\n')
}