MySQL :: MySQL Connector/J 8.0 Developer Guide :: 7.3 Using JDBC CallableStatements to Execute Stored Procedures

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MySQL Connector/J 8.0 Developer Guide / JDBC Concepts / Using JDBC CallableStatements to Execute Stored Procedures Connector/J exposes stored procedure functionality through JDBC's


   CallableStatement

interface. The following example shows a stored procedure that returns the value of


   inOutParam

incremented by 1, and the string passed in using


   inputParam

as a


   ResultSet

Example 7.3 Connector/J: Calling Stored Procedures

CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), \
                        INOUT inOutParam INT)
BEGIN
    DECLARE z INT;
    SET z = inOutParam + 1;
    SET inOutParam = z;
    SELECT inputParam;
    SELECT CONCAT('zyxw', inputParam);
            Notice that you have to use JDBC escape syntax, and that the
            parentheses surrounding the parameter placeholders are not
            optional:
Example 7.4 Connector/J: Using Connection.prepareCall()
import java.sql.CallableStatement;
    // Prepare a call to the stored procedure 'demoSp'
    // with two parameters
    // Notice the use of JDBC-escape syntax ({call ...})
    CallableStatement cStmt = conn.prepareCall("{call demoSp(?, ?)}");
    cStmt.setString(1, "abcdefg");
              Connection.prepareCall() is an
              expensive method, due to the metadata retrieval that the
              driver performs to support output parameters. For
              performance reasons, minimize unnecessary calls to
              Connection.prepareCall() by reusing
              CallableStatement instances in your
              code.
            To retrieve the values of output parameters (parameters
            specified as OUT or
            INOUT when you created the stored
            procedure), JDBC requires that they be specified before
            statement execution using the various
            registerOutputParameter() methods in
            the CallableStatement interface:
Example 7.5 Connector/J: Registering output parameters
import java.sql.Types;
// Connector/J supports both named and indexed
// output parameters. You can register output
// parameters using either method, as well
// as retrieve output parameters using either
// method, regardless of what method was
// used to register them.
// The following examples show how to use
// the various methods of registering
// output parameters (you should of course
// use only one registration per parameter).
// Registers the second parameter as output, and
// uses the type 'INTEGER' for values returned from
// getObject()
cStmt.registerOutParameter(2, Types.INTEGER);
// Registers the named parameter 'inOutParam', and
// uses the type 'INTEGER' for values returned from
// getObject()
cStmt.registerOutParameter("inOutParam", Types.INTEGER);
            Input and in/out parameters are set as for
            PreparedStatement objects. However,
            CallableStatement also supports
            setting parameters by name:
Example 7.6 Connector/J: Setting CallableStatement input
                parameters
    // Set a parameter by index
    cStmt.setString(1, "abcdefg");
    // Alternatively, set a parameter using
    // the parameter name
    cStmt.setString("inputParam", "abcdefg");
    // Set the 'in/out' parameter using an index
    cStmt.setInt(2, 1);
    // Alternatively, set the 'in/out' parameter
    // by name
    cStmt.setInt("inOutParam", 1);
            Although CallableStatement supports
            calling any of the Statement execute
            methods (executeUpdate(),
            executeQuery() or
            execute()), the most flexible method to
            call is execute(), as you do not need
            to know ahead of time if the stored procedure returns result
            sets:
Example 7.7 Connector/J: Retrieving results and output parameter values
    boolean hadResults = cStmt.execute();
    // Process all returned result sets
    while (hadResults) {
        ResultSet rs = cStmt.getResultSet();
        // process result set
        hadResults = cStmt.getMoreResults();
    // Retrieve output parameters
    // Connector/J supports both index-based and
    // name-based retrieval
    int outputValue = cStmt.getInt(2); // index-based
    outputValue = cStmt.getInt("inOutParam"); // name-based