I have a config file:
company=My Company
num_users=3
user={
name="John"
age=24
}
user={
name="Anna"
age=27
}
user={
name="Jack"
age=22
}
I'm trying to parse this config file using Java. I tried java.util.Properties but I don't know how to get each single user data.
I still can get company property value using getProperty method.
Please help me with this.
Thanks!
Nothing wrong with having same property name with different value but getProperty(String key) can not differentiate between them as it will return the first value.
Secondly you can not access nested property directly.Right now here getProperty will return whole String including {} as value because that's what your value contains.You may get value and perform some operations to fetch values from that whole String.Because property file should have only key=value format means left hand side should be key and right hand side should be value.That's it.
If you want to store values as you have specified in your code you should go for JSON format than you can store whole JSON data to file and get it back from the file while you want to use it.
If you use java.util.Properties class to load the config file, you will get the following result:
{company=My Company, age=22, user={, name="Jack", }=, num_users=3}
The reason, you could refer to the javaDoc for "public void load(Reader reader)" method of Properties class.
Since you don't describ the detailed syntax format for your config file,
base on your example input, the following sample code could retrive the name=value correctly:
String reg="(\\w+)\\s*=\\s*((?>\\{[^\\{\\}]*\\})|(?>.*$))";
Pattern pMod = Pattern.compile(reg, Pattern.MULTILINE);
Matcher mMod = pMod.matcher(line);
while (mMod.find()) {
System.out.println(mMod.group(1));
System.out.println(mMod.group(2));
}
The output is:
company
My Company
num_users
3
user
{
name="John"
age=24
}
user
{
name="Anna"
age=27
}
user
{
name="Jack"
age=22
}
Related
I am taking a JSON file as input for a class and parsing the values using gson through respective data classes.
I want to call a function that takes a String value as an argument.
The string value allowed is decided from the values parsed from JSON file. Can I somehow check for that string value passed to the function at compile-time & give an error at compile-time?
Or If I can allow only certain values in the argument for the function based on the values from JSON
Detailed Explanation of use case:
I am building a SDK in which a the person using sdk inputs json String. The json is standardised and is parsed in my code.
{
"name": "Test",
"objects": [
{
"name": "object1",
"type": "object1"
}
]
}
Here name values and other values may vary based on the input by the developer using it but key remains same. But we need to call a function using the value in objects name parameter.
fun testMethod(objectName:String)
So developer calls the testMethod as testMethod(object1).
I need to validate object1 parameter based on json but is there any way possible restricting the test method parameter to object1 only & give error at compile time if the developer calls testMethod(obj1)
Right now I parse JSON & have checks inside the testMethod()
Sure it's possible to do, but somehow in different way, that you described. First of all, as you already mentioned this behavior could be done easily. For this purpose we have Objects.requireNotNull() or Guava.Preconditions(). At the same way you can define you checking but this will work on runtime only.
To do in compile time, you need to create Annotation Preprocessor. The same, as did in different libraries, and one of them, could be Lombok, with their NotNull and Nullable. Android annotation just provide mark and bound for IDE warning, but in their case they adding NotNull checking and throw exception for every annotation usage during compile time.
It's not an easy way, but it's what you are looking for.
No, it's impossible check it in compiler time. It's string handling, as numeric calculation.
In my app, I convert string to JSON and JSON to string, passing class descriptor. My aim is record JSON string in a text file to load in SQLite database. This code I've run in my desktop computer not in Android.
data class calcDescr (
...
)
val calc = CalcDescr(...)
// toJson: internal Kotlin data to JSON
val content = Gson().toJson(calc)
//==================
// Testing validity
// ================
// fromJson: JSON to internal Kotlin data.
// It needs pass the class descriptor. Uses *Java* token, but it's *Kotlin*
var testModel = Gson().fromJson(content, CalcDescr::class.java)
// toJson: internal Kotlin data to JSON again
var contentAgain = Gson().toJson(testModel)
// shoul be equal!
if (content == contentAgain) println("***ok***")
In my file, I write the variable content in a file
We have some web services which are being consumed by mobile clients , in which the mobile clients make some request's and we return response to them. Somehow if the client make any invalid request we throw Custom Exceptions .But recently the mobile client has made some request which was out of range for Long variable. The client has different variables for ex ::
{
"accountId":"343"
"Amount":"90909090909090909090"
}
In case of the value for accountId or Amount are made more than 19 digits we get HttpMessageNotReadable exception as the range is out of long value. But from exception i am not able to fetch for which variable the exception has been raised whether for accountId or Amount. From the exception i am getting this information in _path variable but i am not able to fetch it.
And in the path variable i get something like::
[com.Upload["AccountInfo"], com.Info["Account"]]
Does somebody know how to fetch this information.
The following code prints out the field which causes the exception.
InvalidFormatException invalidFormatException = (InvalidFormatException) exception
.getCause();
System.out.println(invalidFormatException.getPath().get(0)
.getFieldName());
#ArunM's answer works as long as the field is in 1st level viz the example given by OP.
But what happens when the field is in nested json? say paymentType has wrong value in the following example?
{
"userType": "CUSTOMER",
"payment": {
"amount": 123456,
"paymentType": "INTERNET_BANKING"
}
}
In the above example, if there's anything wrong with the value of userType, there will be just one element in _path.
But if any value inside the payment is wrong, say for example paymentType, there will be multiple elements in the _path variable. Each element representing the hierarchical attribute.
So for paymentType, _path will have 2 elements as illustrated below:
_path[0].fieldName = "payment"
_path[1].fieldName = "paymentType"
Hence the correct approach is to get the last element in _path as shown below. If needed, we can build the complete path by using all the elements.
InvalidFormatException ifx = (InvalidFormatException) exception.getCause();
System.out.println(ifx.getPath().get(ifx.size() - 1).getFieldName());
This I believe is the right approach to get the invalid attribute name.
I have a model which is in XML format as shown below and I need to parse the XML and check whether my XML has internal-flag flag set as true or not. In my other models, it might be possible, that internal-flag flag is set as false. And sometimes, it is also possible that this field won't be there so by default it will be false from my code.
<?xml version="1.0"?>
<ClientMetadata
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.google.com client.xsd"
xmlns="http://www.google.com">
<client id="200" version="13">
<name>hello world</name>
<description>hello hello</description>
<organization>TESTER</organization>
<author>david</author>
<internal-flag>true</internal-flag>
<clock>
<clock>
<for>
<init>val(tmp1) = 1</init>
<clock>
<eval><![CDATA[result("," + $convert(val(tmp1)))]]></eval>
</clock>
</for>
<for>
<incr>val(tmp1) -= 1</incr>
<clock>
<eval><![CDATA[result("," + $convert(val(tmp1)))]]></eval>
</clock>
</for>
</clock>
</clock>
</client>
</ClientMetadata>
I have a POJO in which I am storing my above model -
public class ModelMetadata {
private int modelId;
private String modelValue; // this string will have my above XML data as string
// setters and getters here
}
Now what is the best way to determine whether my model has internal-flag set as true or not?
// this list will have all my Models stored
List<ModelMetadata> metadata = getModelMetadata();
for (ModelMetadata model : metadata) {
// my model will be stored in below variable in XML format
String modelValue = model.getModelValue();
// now parse modelValue variable and extract `internal-flag` field property
}
Do I need to use XML parsing for this or is there any better way to do this?
Update:-
I have started using Stax and this is what I have tried so far but not sure how can I extract that field -
InputStream is = new ByteArrayInputStream(modelValue.getBytes());
XMLStreamReader r = XMLInputFactory.newInstance().createXMLStreamReader(is);
while(r.hasNext()) {
// now what should I do here?
}
There is an easy solution using XMLBeam (Disclosure: I'm affiliated with that project), just a few lines:
public class ReadBoolean {
public interface ClientMetaData {
#XBRead("//xbdefaultns:internal-flag")
boolean hasFlag();
}
public static void main(String[] args) throws IOException {
ClientMetaData clientMetaData = new XBProjector().io().url("res://xmlWithBoolean.xml").read(ClientMetaData.class);
System.out.println("Has flag:"+clientMetaData.hasFlag());
}
}
This program prints out
Has flag:true
for your XML.
You could also do some simple string parsing, but this will only work for small cases with proper XML and if there's only a single <internal-flag> element.
This is a simple solution to your problem without using any XML parsing utilities. Other solutions may be more robust or powerful.
Find the index of the string literal <internal-flag>. If it doesn't exist, return false.
Go forward "<internal-flag>".length (15) characters. Read up to the next </internal-flag>, which should be the string true or false.
Take that string, use Boolean.parseBoolean(String) to get a boolean value.
If you want me to help you out with the code just drop a comment!
If you are willing to consider adding Groovy to your mix (e.g. see the book Making Java Groovy) then using a Groovy XMLParser and associated classes will make this simple.
If you need to stick to Java, let me put in a shameless plug for my Xen library, which mimics a lot of the "Groovy way". The answer to your question would be:
Xen doc = new XenParser().parseText(YOUR_XML_STRING);
String internalFlag = doc.getText(".client.internal-flag");
boolean isSet = "true".equals(internalFlag);
If the XML comes from a File, Stream, or URI, that can be handled too.
Caveat emptor, (even though it is free) this is a fairly new library, written solely by a random person (me), and not thoroughly tested on all the crazy XML out there. If anybody knows of a similar, more "mainstream" library I'd be very interested in hearing about it.
I want to retrieve all data properties set for an individual of any class using owl api. The code i have used is
OWLNamedIndividual inputNoun = df.getOWLNamedIndividual(IRI.create(prefix + "Cow"));
for (OWLDataProperty prop: inputNoun.getDataPropertiesInSignature())
{
System.out.println("the properties for Cow are " + prop); //line 1
}
This code compiles with success but line 1 print nothing at all. What should be the correct syntax. Have thoroughly googled and couldnt find any thing worth it.
OWLNamedIndividual::getDataPropertiesInSignature() does not return the properties for which the individual has a filler, it returns the properties that appear in the object itself. For an individual this is usually empty. The method is on the OWLObject interface, which covers things like class and property expressions and ontologies, for which it has a more useful output.
If you want the data properties with an actual filler for an individual, use OWLOntology::getDataPropertyAssertionAxioms(OWLIndividual), like this:
OWLNamedIndividual input = ...
Set<OWLDataPropertyAssertionAxiom> properties=ontology.getDataPropertyAssertionAxioms(input);
for (OWLDataPropertyAssertionAxiom ax: properties) {
System.out.println(ax.getProperty());
}
I have a JSON String stored in a database. In one of my JSP pages, I retrieve this string, and I want to be able to pass the String or the JSON object into Javascript function. The function is simply this for test purposes
function test(h){
alert(h);
}
Now I can retrieve the JSON string from the database fine, I have printed it out to the screen to ensure that it is getting it, however when I pass it in like this
<input type="button"
name="setFontButton"
value="Set"
class="form_btn_primary"
onclick="test('<%=theJSON%>'); return false;"/>
Nothing happens. I used firebug to check what was wrong, and it says there is invalid character.
So I then tried passing in the JSON object like so
Widget widg = mapper.readValue(testing.get(0), Widget.class);
Then pass in it
onclick="test('<%=widg%>'); return false;"/>
Now this will pass in without an error, and it alerts the object name, however I am unable to parse it. Object comes in like with the package name of where the widget class is stored like so
com.package.mode.Widget#ba8af9
I tried using Stringify, but that doesn't seem to work on this Jackson JSON object.
After all that failed, I tried a last resort of taking the String from the database, and encoding it in base64. However, this too fails if I do this
String test = Base64.encode(theString);
and pass that in. However if I do that, print it out to the screen, then copy what is printed out, and send that through it works, so don't quite understand why that is.
So could someone please tell me what I am doing wrong. I have tried soo many different solutions and nothing is working.
The JSON String is stored in database like this
{
"id":1,
"splits":[
{
"texts":[
{
"value":"Test",
"locationX":3,
"locationY":-153,
"font":{
"type":"Normal",
"size":"Medium",
"bold":false,
"colour":"5a5a5a",
"italics":false
}
}
]
}
]
}
Would be very grateful if someone could point me in the direct direction!!
Edit:
Incase anyone else has same problem do this to pass the JSON from JSP to the JS function
<%=theJSON.replaceAll("\"", "\\\'")%>
That allows you to pass the JSON in,
then to get it back in JavaScript to normal JSON format
theJSON = theJSON.replace(/'/g,'"');
Should work fine
I think the combination of double quotes wrapping the onclick and the ones in your JSON may be messing you up. Think of it as if you entered the JSON manually -- it would look like this:
onclick="test('{ "id":1, "splits":[ { "texts":[ { "value":"Test", "locationX":3, "locationY":-153, "font":{ "type":"Normal", "size":"Medium", "bold":false, "colour":"5a5a5a", "italics":false } } ] } ] }'); return false;"
and the opening double quote before id would actually be closing the double quote following onclick= (You should be able to verify this by looking at the page source). Try specifying the onclick as:
onclick='test(\'<%=theJSON%>\'); return false;'
You can follow the following steps
Fetch the jon string
Using the jackson or any other JSON jar file , convert the json string to json array and print the string using out.println.
Call this jsp which prints the json string
check in the firebug , you will be able to see your json .
If the Json string does not print , there can be some problems in your json format.
this is a good website for json beautification , http://jsbeautifier.org/ , really makes the string simple to read .
Thanks
Abhi