Develop Reference

Android toLowerCase() issue with accented characters

My app has a feature to filter content based on some keywords.
This is case insensitive so in order to work I first call String.toLowerCase() on the source content.
The issue I have is when the source is in upper case and contains accentuated characters like with the french word: "INVITÉ"
This word when set to lowercase using the device default locale returns "invité"
The problem is that the last character is not the same as the lowercase character "é"
Instead it's the combination of 2 chars:
"e" 101 &
" ' " 769
Because of this "invité" does not match "invité"
How can I solve this? I would prefer not to remove accentuated characters altogether

You should normalize the string like this.
String upper = "INVITÉ";
System.out.println(upper + " length=" + upper.length());
String lower = upper.toLowerCase();
System.out.println(lower + " length=" + lower.length());
String normalized = Normalizer.normalize(lower, Normalizer.Form.NFC);
System.out.println(normalized + " length=" + normalized.length());
output:
INVITÉ length=7
invité length=7
invité length=6
It also works for Japanese.
String japanese = "が";
System.out.println(japanese + " length=" + japanese.length());
String normalized = Normalizer.normalize(japanese, Normalizer.Form.NFC);
System.out.println(normalized + " length=" + normalized.length());
output:
が length=2
が length=1

The "+" operator is not working in my code

It's so weird that the String + operation has a bug:
String path = "/app/" + monPHost.getUsername() + "/app/" + monProcessInfo.getRegion() + "/tf/bin";
System.out.println("here it ...." + path);
This is the result:
here it ..../app/aiams/app/791
Where has the "/tf/bin" gone?

Maybe monProcessInfo.getRegion() is ending with a carriage return. Try to pre-process it, strip it, and the concatenate with your string.
OR, try this:
String path = "/app/" + monPHost.getUsername() + "/app/" + monProcessInfo.getRegion();
path = path + "/tf/bin";
System.out.println("here it ...." + path);

As a quick work around for all the spaces you're getting:
String path = "/app/" + monPHost.getUsername() + "/app/" + monProcessInfo.getRegion().trim() + "/tf/bin";
System.out.println("here it ...." + path);
I recommend tracking this down in your process object and fixing it there, if you only ever expect an Integer result try to return one, failing fast & early can prevent a lot of downstream bugs.

Given in comment you mentioned monProcessInfo.getRegion() is giving you a String with lots of spaces, and you haven't mentioned the type of return for this method, here is what you may do:
If it is returning a String:
It will be as easy as
String path = "...." + monProcessInfo.getRegion().trim() + "/tf/bin";
If it is returning something else:
Given String concat in Java is relying on Object.toString(), you can change it to:
String path = "...." + monProcessInfo.getRegion().toString().trim() + "/tf/bin";

Since you mentioned that monProcessInfo.getRegion() returns lots of spaces, you can try trimming it before appending it to the later part of the string.
StringBuilder sb = new StringBuilder();
sb.append("/app/" + monPHost.getUsername() + "/app/");
String region = ("" + monProcessInfo.getRegion()).trim();
sb.append(region + "/tf/bin");
System.out.println("here it ...." + sb.toString());

Digits are getting deleted when splitting a string

I have a string from which I need to remove all mentioned punctuations and spaces. My code looks as follows:
String s = "s[film] fever(normal) curse;";
String[] spart = s.split("[,/?:;\\[\\]\"{}()\\-_+*=|<>!`~##$%^&\\s+]");
System.out.println("spart[0]: " + spart[0]);
System.out.println("spart[1]: " + spart[1]);
System.out.println("spart[2]: " + spart[2]);
System.out.println("spart[3]: " + spart[3]);
I have a string from which I need to remove all mentioned punctuations and spaces. My code looks as follows:
String s = "s[film] fever(normal) curse;";
String[] spart = s.split("[,/?:;\\[\\]\"{}()\\-_+*=|<>!`~##$%^&\\s+]");
System.out.println("spart[0]: " + spart[0]);
System.out.println("spart[1]: " + spart[1]);
System.out.println("spart[2]: " + spart[2]);
System.out.println("spart[3]: " + spart[3]);
But, I am getting some elements which are blank. The output is:
spart[0]: s
spart[1]: film
spart[2]:
spart[3]: normal

- is a special character in PHP character classes. For instance, [a-z] matches all chars from a to z inclusive. Note that you've got )-_ in your regex.

- defines a range in regular expressions as used by String.split argument so that needs to be escaped
String[] part = line.toLowerCase().split("[,/?:;\"{}()\\-_+*=|<>!`~##$%^&]");

String[] spart = s.split("[,/?:;\\[\\]\"{}()\\-_+*=|<>!`~##$%^&\\s]+");

Java Split a String with Regex expression

I don't know much about regex. So can you please tell me how to split the below string to get the desired output?
String ruleString= "/Rule/Account/Attribute[N='accountCategory' and V>=1]"+
" and /Rule/Account/Attribute[N='accountType' and V>=34]"+
" and /Rule/Account/Attribute[N='acctSegId' and V>=341]"+
" and /Rule/Account/Attribute[N='is1sa' and V>=1]"+
" and /Rule/Account/Attribute[N='isActivated' and V>=0]"+
" and /Rule/Account/Attribute[N='mogId' and V>=3]"+
" and /Rule/Account/Attribute[N='regulatoryId' and V>=4]"+
" and /Rule/Account/Attribute[N='vipCode' and V>=5]"+
" and /Rule/Subscriber/Attribute[N='agentId' and V='346']​";
Desired output:
a[0] = /Rule/Account/Attribute[N='accountCategory' and V>=1]
a[1] = /Rule/Account/Attribute[N='accountType' and V>=34]
.
.
.
a[n] = /Rule/Subscriber/Attribute[N='agentId' and V='346']
We can not simply split a string using " and " as we have two of those in the string (one is required and other one is not)
I want to split it something like this
String[] splitArray= ruleString.split("] and ");
But this won't work, as it will remove the end bracket ] from each of the splits.

Split your input according to the below regex.
String[] splitArray= ruleString.split("\\s+and\\s+(?=/)");
This splits the input according to the and which exits just before to the forward slash.

You have to use look-behind here:
String[] splitArray= ruleString.split("(?<=\\])\\s*and\\s*");

writing a specific string to a file with Java

my codes dont seem to properly address what i intend to achieve.
a long string instead of a well broken and seperated string
it does not handle the 'seperator' appropriately ( produces , instead of ",")
also the 'optional' ( produces ' instead of " '")
Current result:
LOAD DATA INFILE 'max.csv'BADFILE 'max.bad'DISCARDFILE
'max.dis' APPEND INTO TABLEADDRESSfields terminated by,optionally enclosed
by'(ID,Name,sex)
the intended result should look like this
is there a better way of doing this or improving the above codes

Yeah. Use the character \n to start a new line in the file, and escape " characters as \". Also, you'll want to add a space after each variable.
content = " LOAD DATA\nINFILE "+ fileName + " BADFILE "+ badName + " DISCARDFILE " +
discardName + "\n\nAPPEND\nINTO TABLE "+ table + "\n fields terminated by \"" + separator
+ "\" optionally enclosed by '" + optional + "'\n (" + column + ")";
This is assuming fileName, badName, and discardName include the quotes around the names.

Don't reinvent the wheel... the apache commons-io library does all that in one line:
FileUtils.write(new File(controlName), content);
Here's the javadoc for FileUtils.write(File, CharSequence):
Writes a CharSequence to a file creating the file if it does not exist

To insert a new line you need to use \n or \r\n for windows
for example
discardName + "\n" //New line here
"APPEND INTO TABLE"
For the double quote symbol on the other hand you need to specifically type \" around the comma:
"fields terminated by \"" + separator +"\""
which will produce this ","
and that is similar to what the optional variable needs to be