problem with utf8 in java

Question

I have the following table:

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create table test
(
  fname char(20) character set utf8 collate utf8_turkish_ci,
  id int primary key
);

I am inserting data as follows:

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resultSet.executeQuery("set namee utf8");
preparedStatement = connection.prepareStatement("insert into test(fname) values(?)");
preparedStatement.setstring(1,"alis");
preparedStatement.executeUpdate();

But when I retrieve data they are resemble to ?????.

What is problem and how can I solve that?

Answer 1

As per the MySQL JDBC driver documentation you need to set the character encoding in the JDBC connection URL as well. Here's an example:

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jdbc:mysql://localhost:3306/db_name?useUnicode=yes&characterEncoding=UTF-8

Otherwise the MySQL JDBC driver will use the platform default encoding to convert the characters to bytes before sending over network, which is in your case apparently not UTF-8. All uncovered characters will then be replaced by question marks.

Also, when retrieving the data, you need to ensure that the console/file where you're displaying/writing the characters to also supports/uses UTF-8. Otherwise they will become question marks as well. How to fix that depends on how/where you're displaying/writing those characters to.

See also:

• Unicode - How to get the characters right?

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By the way, you don't need the SET NAMES query here.