Java MySQL Encoding issue with UTF-8 - java

I have an issue inserting a pdf text into a mysql table. The error message is as follows:
" Incorrect string value: '\xF0\x9D\x9B\xBC i...' for column 'text' at row 1"
I know that this code refers to the greek letter alpha. However, I have set 'characer set' to UTF-8 for the column text but also in the mysql connection. Also, I have tried uft8mb4. However, none of it worked.
The greek letter alpha occurs in different font types. I am not sure if this matters.
Any ideas why this does not work?
I also created a pdf file myself which contained an alpha in the text. For this example, my programme runs without any errors. Although I know that the error message refers to the alpha, there seems to be an additional issue.
Thanks in advance!
UPDATE:
After some checking, I found that some really strange symbols were created from a formula which contained the greek letter alpha. So, apparently these unknown symbols led to the error.
However, I still do not know how to exclude any unknown symbols from the text. What is the easiest way to do this?
These are the symbols:

I restricted the string in Java to only latin symbols. maybe that's not the most general way of getting rid of those strange symbols but it works for now.

In MySQL, use CHARACTER SET utf8mb4.
Add ?useUnicode=yes&characterEncoding=UTF-8 to the JDBC URL

Related

Display special characters using entity or hex values

I am trying to display ŵ through my jsf page but unable to do so. Basically the text with special characters is read from properties file , but on my application screen it becomes something else . I did try to use entity values but not succeeding for example if original text is :
ŵyhsne klqdw dwql
then after replacing with with entity or hexvalues:
**&wcirc ;**yhsne klqdw dwql but in my page it displays as it is
I can just guess your question. Please edit it and improve it.
If you are displaying in web, you should use ŵ (note: without spaces), but this also requires a fonts on client site that support such character.
If the string is in your code: replace the character with \u0175.
But probably the best way it is to use just ŵ either in code on in web, or on any file, and you should assure that such files (or sources) are interpreted ad UTF-8, and you deliver pages are UTF-8. If you are not using UTF-8, just check in similar way, that you are using consistently the correct encoding.
And sending a character doesn't mean it could be displayed. There is always the possibility that a font will not have all *special" characters in it.

Unable to insert UTF-8 characters in mysql [duplicate]

I tried to use UTF-8 and ran into trouble.
I have tried so many things; here are the results I have gotten:
???? instead of Asian characters. Even for European text, I got Se?or for Señor.
Strange gibberish (Mojibake?) such as Señor or 新浪新闻 for 新浪新闻.
Black diamonds, such as Se�or.
Finally, I got into a situation where the data was lost, or at least truncated: Se for Señor.
Even when I got text to look right, it did not sort correctly.
What am I doing wrong? How can I fix the code? Can I recover the data, if so, how?
This problem plagues the participants of this site, and many others.
You have listed the five main cases of CHARACTER SET troubles.
Best Practice
Going forward, it is best to use CHARACTER SET utf8mb4 and COLLATION utf8mb4_unicode_520_ci. (There is a newer version of the Unicode collation in the pipeline.)
utf8mb4 is a superset of utf8 in that it handles 4-byte utf8 codes, which are needed by Emoji and some of Chinese.
Outside of MySQL, "UTF-8" refers to all size encodings, hence effectively the same as MySQL's utf8mb4, not utf8.
I will try to use those spellings and capitalizations to distinguish inside versus outside MySQL in the following.
Overview of what you should do
Have your editor, etc. set to UTF-8.
HTML forms should start like <form accept-charset="UTF-8">.
Have your bytes encoded as UTF-8.
Establish UTF-8 as the encoding being used in the client.
Have the column/table declared CHARACTER SET utf8mb4 (Check with SHOW CREATE TABLE.)
<meta charset=UTF-8> at the beginning of HTML
Stored Routines acquire the current charset/collation. They may need rebuilding.
UTF-8 all the way through
More details for computer languages (and its following sections)
Test the data
Viewing the data with a tool or with SELECT cannot be trusted.
Too many such clients, especially browsers, try to compensate for incorrect encodings, and show you correct text even if the database is mangled.
So, pick a table and column that has some non-English text and do
SELECT col, HEX(col) FROM tbl WHERE ...
The HEX for correctly stored UTF-8 will be
For a blank space (in any language): 20
For English: 4x, 5x, 6x, or 7x
For most of Western Europe, accented letters should be Cxyy
Cyrillic, Hebrew, and Farsi/Arabic: Dxyy
Most of Asia: Exyyzz
Emoji and some of Chinese: F0yyzzww
More details
Specific causes and fixes of the problems seen
Truncated text (Se for Señor):
The bytes to be stored are not encoded as utf8mb4. Fix this.
Also, check that the connection during reading is UTF-8.
Black Diamonds with question marks (Se�or for Señor);
one of these cases exists:
Case 1 (original bytes were not UTF-8):
The bytes to be stored are not encoded as utf8. Fix this.
The connection (or SET NAMES) for the INSERT and the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Case 2 (original bytes were UTF-8):
The connection (or SET NAMES) for the SELECT was not utf8/utf8mb4. Fix this.
Also, check that the column in the database is CHARACTER SET utf8 (or utf8mb4).
Black diamonds occur only when the browser is set to <meta charset=UTF-8>.
Question Marks (regular ones, not black diamonds) (Se?or for Señor):
The bytes to be stored are not encoded as utf8/utf8mb4. Fix this.
The column in the database is not CHARACTER SET utf8 (or utf8mb4). Fix this. (Use SHOW CREATE TABLE.)
Also, check that the connection during reading is UTF-8.
Mojibake (Señor for Señor):
(This discussion also applies to Double Encoding, which is not necessarily visible.)
The bytes to be stored need to be UTF-8-encoded. Fix this.
The connection when INSERTing and SELECTing text needs to specify utf8 or utf8mb4. Fix this.
The column needs to be declared CHARACTER SET utf8 (or utf8mb4). Fix this.
HTML should start with <meta charset=UTF-8>.
If the data looks correct, but won't sort correctly, then
either you have picked the wrong collation,
or there is no collation that suits your need,
or you have Double Encoding.
Double Encoding can be confirmed by doing the SELECT .. HEX .. described above.
é should come back C3A9, but instead shows C383C2A9
The Emoji 👽 should come back F09F91BD, but comes back C3B0C5B8E28098C2BD
That is, the hex is about twice as long as it should be.
This is caused by converting from latin1 (or whatever) to utf8, then treating those
bytes as if they were latin1 and repeating the conversion.
The sorting (and comparing) does not work correctly because it is, for example,
sorting as if the string were Señor.
Fixing the Data, where possible
For Truncation and Question Marks, the data is lost.
For Mojibake / Double Encoding, ...
For Black Diamonds, ...
The Fixes are listed here. (5 different fixes for 5 different situations; pick carefully): http://mysql.rjweb.org/doc.php/charcoll#fixes_for_various_cases
I had similar issues with two of my projects, after a server migration. After searching and trying a lot of solutions, I came across with this one:
mysqli_set_charset($con,"utf8mb4");
After adding this line to my configuration file, everything works fine!
I found this solution for MySQLi—PHP mysqli set_charset() Function—when I was looking to solve an insert from an HTML query.
I was also searching for the same issue. It took me nearly one month to find the appropriate solution.
First of all, you will have to update you database will all the recent CHARACTER and COLLATION to utf8mb4 or at least which support UTF-8 data.
For Java:
while making a JDBC connection, add this to the connection URL useUnicode=yes&characterEncoding=UTF-8 as parameters and it will work.
For Python:
Before querying into the database, try enforcing this over the cursor
cursor.execute('SET NAMES utf8mb4')
cursor.execute("SET CHARACTER SET utf8mb4")
cursor.execute("SET character_set_connection=utf8mb4")
If it does not work, happy hunting for the right solution.
Set your code IDE language to UTF-8
Add <meta charset="utf-8"> to your webpage header where you collect data form.
Check your MySQL table definition looks like this:
CREATE TABLE your_table (
...
) ENGINE=InnoDB DEFAULT CHARSET=utf8
If you are using PDO, make sure
$options = array(PDO::MYSQL_ATTR_INIT_COMMAND=>'SET NAMES utf8');
$dbL = new PDO($pdo, $user, $pass, $options);
If you already got a large database with above problem, you can try SIDU to export with correct charset, and import back with UTF-8.
Depending on how the server is setup, you have to change the encode accordingly. utf8 from what you said should work the best. However, if you're getting weird characters, it might help if you change the webpage encoding to ANSI.
This helped me when I was setting up a PHP MySQLi. This might help you understand more: ANSI to UTF-8 in Notepad++

SWT/JFace TableViewer not showing Unicode characters

I'm using a TableViewer for showing some data in my app. The problem is that this widget is not showing Unicode characters, and I don't understand why?
Is there a way to solve this?
Edit: I've made a debugging session. I think the problem isn't the Table, but the ArrayList where strings are stored.
The program loads a byte[] array and decodes it, generating Unicode strings. In my previous app it appears that the list is correctly stored, but in the new one (with the same way to generate strings) unicode special characters like 'è' are not stored correctly. Why?
I've solved it ;)
The trick was to use UTF-8 instead of UTF-16 (Eclipse did the job for me)

Cleaning an inputstring containing binary junk to produce an ascii printable string

In our application we have a textfield that is controlled by TinyMCE. If the customer pastes text from Word into the textfield, Oracle balks when we are trying to store this text in our database:
ORA-01461: can bind a LONG value only for insert into a LONG column
Cleaning the text in, say Notepad, will not produce any problems, so my guess is that the problem lies in the input string containing some kind of binary junk that Oracle uses as a delimiter between the values that are used in the sql insert string.
Upgrading our ancient TinyMCE will probably fix the problem, but I also want to ensure the text really is clean when passed to the lower layers. So I thought that I might ensure the text is true ASCII, and if not, clean everything that does not pass as ASCII by looping through the lines in the input and do the following:
line.replaceAll("[^\\p{ASCII}]", "")
Is this a viable solution, and if not, what are the pitfalls?
What about cleaning the pastes content like i described here?
This might also remove junk.

encountering a square or null or ? mark in retrieving utf-8 characters from mysql database in java

There is no problem when I try to insert this symbol "ñÑ" in the mysql database. However, when I try to retrieve the same data the symbol or character that was selected by the query would appear as null value or something like a ? or a square.
Please help me with these I have been troubled many weeks by these problems. I just cannot understand anymore. I have written the code in java.
The "�" is the replacement character, used when something processing characters can't display or otherwise handle a character. A box is sometimes used for the same purpose, or indicates that the font being used doesn't have a glyph for some character.
To resolve this, check that the character sets being used for the various components, such as the column and connection, are correct.
See also: "Setting the default Java character encoding?"

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