CODEWITHSUNDEEP
javajdbc
Rabin
Rabin

Reputation: 1583

Is there any way to prevent Java from turning my double into exponential value?

Is there anyway to prevent Java from turning my double into exponential value? I am having problem with saving that into my database. It keep telling me that it can not convert my VarChar into numeric.

I do;

amt = oldAmt - amt;
amt = Math.abs(amt);

And put the value in amt like so using setter;

jvd.setDr_amt(amt);

Then generate a query string using a function and it give me;

INSERT INTO jv ( id, dr_amt) VALUES (1, 1.595545786E7);

The datatype in the database for dr_amt is numeric(15, 2)

Anyone?

Upvotes: 1

Views: 1733

Answers (2)

Alnitak
Alnitak

Reputation: 339836

You should be using JDBC prepared statements, with bound parameters, e.g.

PreparedStatement s = c.prepareStatement(
        "INSERT INTO mytable (myfield) VALUES (?)");
s.setDouble(1, n);
s.executeUpdate();

[exception handling code omitted]

The JDBC layer will ensure that your double variable is correctly sent to the database server without getting mangled.

Upvotes: 4

Lukas Eder
Lukas Eder

Reputation: 220952

I'm very much guessing that you do something like this:

connection.createStatement().executeUpdate(
  "INSERT INTO my_table VALUES('" + myDouble + "')");

Don't do that for the following reasons:

  • Concatenating strings will cause syntax errors
  • Concatenating strings will cause SQL injection

Write your statement in a way to let JDBC handle data types:

PreparedStatement stmt = connection.prepareStatement(
  "INSERT INTO my_table VALUES(?)");
stmt.setDouble(1, myDouble);
stmt.executeUpdate();

If you absolutely must inline your double value in your SQL string instead of using bind values, try using BigDecimal to serialise your double, instead:

new BigDecimal(myDouble).toString();

Since you seem to be operating on monetary values, you should change all your doubles to BigDecimal anyway, as BigDecimal is Java's best match for SQL's DECIMAL data type

Upvotes: 7

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