Develop Reference

Is there way to wrap string with single quotes in Prepared statement setString()?

I have this column in a MySQL table which has a JSON string and I'm trying to pull records using regex.
For example, the column 'paylod' (datatype long text) holds this value
{
"type":"assignment",
"location":"12345"
}
I'm using RLIKE to fetch records based on location.
select * from table where payload RLIKE '"location":"[[:<:]]12345[[:>:]]"';
When using this query in java, I'm using prepared statement.
String pattern = "\"location\":\"[[:<:]]12345[[:>:]]\""
And when I use preparedStatement.setString(payload, pattern), I'm not getting any results back. But when I execute the query in workbench, I see the rows fetched.
I'm guessing it's because I'm using setString, it is wrapping pattern with double quotes and MySQL is not able to parse it.
So is there a way forward? My requirement is to get records based on key-value pair in the JSOn payload column.

Alright, adding escape character in string helped.
String pattern = "'\"location'\":'\"[[:<:]]12345[[:>:]]'\"";
String patternValue = pattern.replaceAll("'","\\\\");
So the string becomes \"location\":\"[[:<:]]12345[[:>:]]\" where \ serves as escape character for " in mysql, when string is wrapped inside ""

Spark adding extra space when record contain a "comma"

My input is a "|" (pipe) separator file. I can't change the input file.
The format is
HEADER_A|HEADER_B|HEADER_C
A|B|C
A D|B| => records without comma generates output like "A D|B|"
A,D|B| => records with comma generates output like " A,D|B| "
Spark config is :
sparkSession.read()
.option("header","true")
.option("delimiter","|")
.schema(schema) * assume this is valid and represents the correct schema
.csv(fileName)
.cache();
I've tried using the "sep" option but didn't work as well.
If my delimiter is "|", why Spark has a different effect on records with a comma?

I found my error. As the record contains a comma, I should not use the .csv(path) when writing the file
Changing from
dataset.write()...
.csv(path)
to
dataset,write()...
.text(path)
solved it

Create Excel files in java(invalid number)

I have a string like "2,345".I want to put it into a excel cell.I successfully did but in my excel file i got "2,345" as a string.So please suggest me how can i get "2,345" as a number value but with the same format as i used above(comma seperated).
Thanks in advance.

Remove the comma before inserting it into Excel, cast it to a number before inserting, then format the column to show the comma.
String replace
In Excel the code to format a Range with commas is:
SomeRange.Style = "Comma" 'or, recorded version
SomeRange.NumberFormat = "_-* #,##0_-;-* #,##0_-;_-* ""-""??_-;_-#_-"
'a simpler version..
SomeRange.NumberFormat = "#,##0"

Special chars in JAVA

สวัสดี Mr.Java Sp'e c'i'a'l'' '
I tried to parse the String using below code but I could't make
simply it shows the wrong value.
String s = "สวัสดี Mr.Java Sp'e c'i'a'l'' '"";
s = s.replaceAll("'", "'");
//s = s.replaceAll("'", "''");
StringEscapeUtils.escapeHtml(s);
I am trying to get from JSP and save in SQL Server DB and show using JSP and update.
But some times in JSP it shows the converted &apos in jsp as it is instead of Special
Chars.
Very Simple is Here I have shown this String(สวัสดี Mr.Java Sp'e c'i'a'l'' ') in StackOverflow they
save in their DB and Shows and allows me to update this is what I
wanted.

OK. So lets look at what your code does:
// line 1
String s = "สวัสดี Mr.Java Sp'e c'i'a'l'' '";
We have a String with various international characters in it ... and some "'" characters.
// line 2
s = s.replaceAll("'", "'");
Assuming that those are really "'" characters characters, we will replace all instances of "'" with an XML / HTML character entity giving us:
"สวัสดี Mr.Java Sp'e c'i'a'l'' '"
And so ...
// line 3
s = StringEscapeUtils.escapeHtml(s);
This replaces any active HTML / XML characters with character references. This includes the ampersand characters "&" that you previously inserted. The result is this:
"&#xxxx;&#xxxx;&#xxxx;&#xxxx; Mr.Java Sp'e
c'i'a'l'' '"
(The &#xxxx; numeric character references encode those Thai (?) characters.)
When you embed that in an HTML document and display it, you will see "สวัสดี Mr.Java Sp'e c'i'a'l'' '"
See what has happened? You have HTML escaped your HTML escaped apostrophies!!
So what do you really need to do?
There is no need replace apostrophes with '. Apostrophes are legal in HTML text.
There should be no need to add HTML escapes so that you can store text in a database:
Any modern database will allow you to store Unicode strings without any special encoding.
If you are trying to prevent the database's SQL parser getting confused by quotes in the text you are storing, you are doing it the wrong way. The right way to do this is to use a PreparedStatement, add parameter placeholders to the query, and use the PreparedStatement.setXxx methods to provide the parameter values. The execute (or whatever) will take care of any SQL escaping that needs to be done.

Java POST data to mySQL UTF-8 encoding issue

I have POST data that contains the Japanese string AKB48 ネ申テレビ シーズン3, defined in jQuery as data.
$("#some_div").load("someurl", { data : "AKB48 ネ申テレビ シーズン3"})
The post data is sent to Java Servlet:
String data = new String(this.request.getParameter("data").getBytes("ISO-8859-1"), "UTF-8");
My program saves it to MySQL, but after the data is saved to the database it becomes:
AKB48 u30CDu7533u30C6u30ECu30D3 u30B7u30FCu30BAu30F33
What should I do if I want to save it as it is in UTF-8? All my files are in UTF-8.
MySQL encoding is utf8 and here is the code
String sql = "INSERT INTO Inventory (uid, item_id, item_data, ctime) VALUES ("
+ inventory.getUid() + ",'"
+ inventory.getItemId() + "','"
+ StringEscapeUtils.escapeJava(inventory.getItemData()) + "',CURRENT_TIMESTAMP)";
Statement stmt = con.createStatement();
int cnt = stmt.executeUpdate(sql);

From your example above, I can verify that the Japanese string is getting saved to your MySQL database correctly, but as escaped Unicode.
I would check these items in order:
Are your tables and columns all set to have a character set and collation for utf8? I.e.,
CHARACTER SET utf8 COLLATE utf8_general_ci
Are explicitly setting the character set encoding before POST? request.setCharacterEncoding("UTF-8");
Are you setting the character encoding for your db connections? I.e., jdbc:mysql://localhost:3306/YOURDB?useUnicode=true&characterEncoding=UTF8
As the others have pointed out, you should not use that getBytes trick. It will surely mess up the POSTed values.
EDIT
Do not use StringEscapeUtils.escapeJava, since that will turn your string into escaped Unicode. That is what is transforming AKB48 ネ申テレビ シーズン3 into AKB48 u30CDu7533u30C6u30ECu30D3 u30B7u30FCu30BAu30F33.

Why you do not just extract value of parameter like this.request.getParameter("data")?
Your data is sent correctly using URL encoding where each unicode character is replaced by its code. Then you have to get the value of the parameter. When you are requesting bytes using ISO-8859-1 you are actually corrupting your data because the string is represented as a sequence if codes in textual form.

Java strings are stored in UTF-16. So, this code:
String data = new String(this.request.getParameter("data").getBytes("ISO-8859-1"), "UTF-8");
decodes a UTF-16 string (which has been re-encoded from UTF-8 in the HTTP protocol) into a binary array using the ISO-8859-1 charset, and re-encodes the binary array using the UTF-8 charset. This is almost certainly not what you want.
What happens when you use this?
String data = this.request.getParameter("data");
System.out.println(data);
If the second line generates bad data, then your problem is likely in jQuery. Determine that you are indeed getting unicode in your jQuery request:
System.out.println(this.request.getHeader("Content-Encoding"));
If it does not generate bad data, but the data doesn't get stored correctly in mySQL, your problem is at the database level. Make sure your column type supports unicode strings.

What's the point of the line
String data = new String(this.request.getParameter("data").getBytes("ISO-8859-1"), "UTF-8");
You're transforming chinese (or at least non-occidental) characters into bytes using the ISO-8859-1 encoding. Of course this can't work, since chinese characters are not supported by the ISO-8859-1 encoding. ANd then you're constructing a new String from bytes that are supposed to represent ISO-8859-1-encoded characters, using the UTF-8 encoding. This, once again, doesn't make any sense. UTF-8 and ISO-8859-1 are not the same thing, and only a small set of chars have the same encoding in both formats.
Just use
String data = this.request.getParameter("data");
and everything should be OK, provided that the column in the MySQL table uses an encoding that supports these characters.
EDIT:
now that you've shown us the code used to insert the data in database, I know where all this comes from (the preceding points are still valid, though). You're doing
StringEscapeUtils.escapeJava(inventory.getItemData())
What's the point? escapeJava is used to take a String and escape special characters in order to make it a valid Java String literal. It has nothing to do with SQL. Use a prepared statement:
String sql = "INSERT INTO Inventory (uid, item_id, item_data, ctime) VALUES (?, ?, ?, CURRENT_TIMESTAMP);
PreparedStatement stmt = con.prepareStatement();
stmt.setInteger(1, inventory.getUid()); // or setLong, depending on the type
stmt.setString(2, inventory.getItemId());
stmt.setString(inventory.getItemData());
int cnt = stmt.executeUpdate();
The PreparedStatement will take care of escaping special SQL characters correctly. They're the best tool agains SQL injection attack, and should always be used when a query has parameters, especially if the parameters come from the end user. See http://docs.oracle.com/javase/tutorial/jdbc/basics/prepared.html.