Get query from java.sql.PreparedStatement

In my code I am using java.sql.PreparedStatement.

I then execute the setString() method to populate the wildcards of the prepared statement.

Is there a way for me to retrieve (and print out) the final query before the executeQuery() method is called and the query is executed? I Just want this for debugging purposes.

This is nowhere definied in the JDBC API contract, but if you're lucky, the JDBC driver in question may return the complete SQL by just calling PreparedStatement#toString(). I.e.

System.out.println(preparedStatement);

To my experience, the ones which currently do so are at least the PostgreSQL 8.x and MySQL 5.x JDBC drivers.

In the case that your JDBC driver doesn't support it, your best bet is using a statement wrapper which records all calls to setXxx() methods and finally populates a SQL string on toString() based on the recorded information. An existing library which does that is P6Spy. In the meanwhile, post an enhancement request to the development team of your JDBC driver and hope that they'll implement the desired toString() behavior as well.

You could try calling toString() on the prepared statement after you've set the bind values.

PreparedStatement statement = connection.prepareStatement(aSQLStatement);
System.out.println("Before : " + statement.toString());
query.setString(1, "Hello");
query.setString(2, "World");
System.out.println("After : " + statement.toString());

This works when you use the JDBC MySQL driver, but I'm not sure if it will in other cases. You may have to keep track of all the bindings you make and then print those out.

Sample output from above code.

Before : com.mysql.jdbc.JDBC4PreparedStatement@fa9cf: SELECT * FROM test WHERE blah1=** NOT SPECIFIED ** and blah2=** NOT SPECIFIED **
After : com.mysql.jdbc.JDBC4PreparedStatement@fa9cf: SELECT * FROM test WHERE blah1='Hello' and blah2='World'

For those of you looking for a solution for Oracle, I made a method from the code of Log4Jdbc. You will need to provide the query and the parameters passed to the preparedStatement since retrieving them from it is a bit of a pain:

private String generateActualSql(String sqlQuery, Object... parameters) {
    String[] parts = sqlQuery.split("\\?");
    StringBuilder sb = new StringBuilder();

    // This might be wrong if some '?' are used as litteral '?'
    for (int i = 0; i < parts.length; i++) {
        String part = parts[i];
        sb.append(part);
        if (i < parameters.length) {
            sb.append(formatParameter(parameters[i]));
        }
    }

    return sb.toString();
}

private String formatParameter(Object parameter) {
    if (parameter == null) {
        return "NULL";
    } else {
        if (parameter instanceof String) {
            return "'" + ((String) parameter).replace("'", "''") + "'";
        } else if (parameter instanceof Timestamp) {
            return "to_timestamp('" + new SimpleDateFormat("MM/dd/yyyy HH:mm:ss.SSS").
                    format(parameter) + "', 'mm/dd/yyyy hh24:mi:ss.ff3')";
        } else if (parameter instanceof Date) {
            return "to_date('" + new SimpleDateFormat("MM/dd/yyyy HH:mm:ss").
                    format(parameter) + "', 'mm/dd/yyyy hh24:mi:ss')";
        } else if (parameter instanceof Boolean) {
            return ((Boolean) parameter).booleanValue() ? "1" : "0";
        } else {
            return parameter.toString();
        }
    }
}

You can add log4jdbc to your project. This adds logging of sql commands as they execute + a lot of other information.

http://code.google.com/p/log4jdbc/wiki/FAQ

If you only want to log the query, then add 'logger' and 'profileSQL' to the jdbc url:

&logger=com.mysql.jdbc.log.Slf4JLogger&profileSQL=true

Then you will get the SQL statement below:

2016-01-14 10:09:43  INFO MySQL - FETCH created: Thu Jan 14 10:09:43 CST 2016 duration: 1 connection: 19130945 statement: 999 resultset: 0
2016-01-14 10:09:43  INFO MySQL - QUERY created: Thu Jan 14 10:09:43 CST 2016 duration: 1 connection: 19130945 statement: 999 resultset: 0 message: SET sql_mode='NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES'
2016-01-14 10:09:43  INFO MySQL - FETCH created: Thu Jan 14 10:09:43 CST 2016 duration: 1 connection: 19130945 statement: 999 resultset: 0
2016-01-14 10:09:43  INFO MySQL - QUERY created: Thu Jan 14 10:09:43 CST 2016 duration: 2 connection: 19130945 statement: 13 resultset: 17 message: select 1
2016-01-14 10:09:43  INFO MySQL - FETCH created: Thu Jan 14 10:09:43 CST 2016 duration: 0 connection: 19130945 statement: 13 resultset: 17
2016-01-14 10:09:43  INFO MySQL - QUERY created: Thu Jan 14 10:09:43 CST 2016 duration: 1 connection: 19130945 statement: 15 resultset: 18 message: select @@session.tx_read_only
2016-01-14 10:09:43  INFO MySQL - FETCH created: Thu Jan 14 10:09:43 CST 2016 duration: 0 connection: 19130945 statement: 15 resultset: 18
2016-01-14 10:09:43  INFO MySQL - QUERY created: Thu Jan 14 10:09:43 CST 2016 duration: 2 connection: 19130945 statement: 14 resultset: 0 message: update sequence set seq=seq+incr where name='demo' and seq=4602
2016-01-14 10:09:43  INFO MySQL - FETCH created: Thu Jan 14 10:09:43 CST 2016 duration: 0 connection: 19130945 statement: 14 resultset: 0

The default logger is:

com.mysql.jdbc.log.StandardLogger

Mysql jdbc property list: https://dev.mysql.com/doc/connector-j/en/connector-j-reference-configuration-properties.html

A bit of a hack, but it works fine for me:

Integer id = 2;
String query = "SELECT * FROM table WHERE id = ?";
PreparedStatement statement = m_connection.prepareStatement( query );
statement.setObject( 1, value );
String statementText = statement.toString();
query = statementText.substring( statementText.indexOf( ": " ) + 2 );

I have made a workaround to solve this problem. Visit the below link for more details http://code-outofbox.blogspot.com/2015/07/java-prepared-statement-print-values.html

Solution:

// Initialize connection
PreparedStatement prepStmt = connection.prepareStatement(sql);

PreparedStatementHelper prepHelper = new PreparedStatementHelper(prepStmt);

// User prepHelper.setXXX(indx++, value);
// .....

try {
   Pattern pattern = Pattern.compile("\\?");
   Matcher matcher = pattern.matcher(sql);
   StringBuffer sb = new StringBuffer();
   int indx = 1;  // Parameter begin with index 1
   while (matcher.find()) {
 matcher.appendReplacement(sb, prepHelper.getParameter(indx++));
   }
   matcher.appendTail(sb);
   LOGGER.debug("Executing Query [" + sb.toString() + "] with Database[" + /*db name*/ + "] ...");
   } catch (Exception ex) {
    LOGGER.debug("Executing Query [" + sql + "] with Database[" +  /*db name*/+ "] ...");
}

/****************************************************/

package java.sql;

import java.io.InputStream;
import java.io.Reader;
import java.math.BigDecimal;
import java.net.URL;
import java.sql.Array;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.Date;
import java.sql.NClob;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.Ref;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.RowId;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.Calendar;

public class PreparedStatementHelper implements PreparedStatement {

 private PreparedStatement prepStmt;
 private String[] values;

 public PreparedStatementHelper(PreparedStatement prepStmt) throws SQLException {
  this.prepStmt = prepStmt;
  this.values = new String[this.prepStmt.getParameterMetaData().getParameterCount()];
 }

 public String getParameter(int index) {
  String value = this.values[index-1];
  return String.valueOf(value);
 }

 private void setParameter(int index, Object value) {
  String valueStr = "";
  if (value instanceof String) {
   valueStr = "'" + String.valueOf(value).replaceAll("'", "''") + "'";
  } else if (value instanceof Integer) {
   valueStr = String.valueOf(value);
  } else if (value instanceof Date || value instanceof Time || value instanceof Timestamp) {
   valueStr = "'" + String.valueOf(value) + "'";
  } else {
   valueStr = String.valueOf(value);
  }
  this.values[index-1] = valueStr;
 }

 @Override
 public ResultSet executeQuery(String sql) throws SQLException {
  return this.prepStmt.executeQuery(sql);
 }

 @Override
 public int executeUpdate(String sql) throws SQLException {
  return this.prepStmt.executeUpdate(sql);
 }

 @Override
 public void close() throws SQLException {
  this.prepStmt.close();

 }

 @Override
 public int getMaxFieldSize() throws SQLException {
  return this.prepStmt.getMaxFieldSize();
 }

 @Override
 public void setMaxFieldSize(int max) throws SQLException {
  this.prepStmt.setMaxFieldSize(max);
 }

 @Override
 public int getMaxRows() throws SQLException {
  return this.prepStmt.getMaxRows();
 }

 @Override
 public void setMaxRows(int max) throws SQLException {
  this.prepStmt.setMaxRows(max);
 }

 @Override
 public void setEscapeProcessing(boolean enable) throws SQLException {
  this.prepStmt.setEscapeProcessing(enable);
 }

 @Override
 public int getQueryTimeout() throws SQLException {
  return this.prepStmt.getQueryTimeout();
 }

 @Override
 public void setQueryTimeout(int seconds) throws SQLException {
  this.prepStmt.setQueryTimeout(seconds);
 }

 @Override
 public void cancel() throws SQLException {
  this.prepStmt.cancel();
 }

 @Override
 public SQLWarning getWarnings() throws SQLException {
  return this.prepStmt.getWarnings();
 }

 @Override
 public void clearWarnings() throws SQLException {
  this.prepStmt.clearWarnings();
 }

 @Override
 public void setCursorName(String name) throws SQLException {
  this.prepStmt.setCursorName(name);
 }

 @Override
 public boolean execute(String sql) throws SQLException {
  return this.prepStmt.execute(sql);
 }

 @Override
 public ResultSet getResultSet() throws SQLException {
  return this.prepStmt.getResultSet();
 }

 @Override
 public int getUpdateCount() throws SQLException {
  return this.prepStmt.getUpdateCount();
 }

 @Override
 public boolean getMoreResults() throws SQLException {
  return this.prepStmt.getMoreResults();
 }

 @Override
 public void setFetchDirection(int direction) throws SQLException {
  this.prepStmt.setFetchDirection(direction);
 }

 @Override
 public int getFetchDirection() throws SQLException {
  return this.prepStmt.getFetchDirection();
 }

 @Override
 public void setFetchSize(int rows) throws SQLException {
  this.prepStmt.setFetchSize(rows);
 }

 @Override
 public int getFetchSize() throws SQLException {
  return this.prepStmt.getFetchSize();
 }

 @Override
 public int getResultSetConcurrency() throws SQLException {
  return this.prepStmt.getResultSetConcurrency();
 }

 @Override
 public int getResultSetType() throws SQLException {
  return this.prepStmt.getResultSetType();
 }

 @Override
 public void addBatch(String sql) throws SQLException {
  this.prepStmt.addBatch(sql);
 }

 @Override
 public void clearBatch() throws SQLException {
  this.prepStmt.clearBatch();
 }

 @Override
 public int[] executeBatch() throws SQLException {
  return this.prepStmt.executeBatch();
 }

 @Override
 public Connection getConnection() throws SQLException {
  return this.prepStmt.getConnection();
 }

 @Override
 public boolean getMoreResults(int current) throws SQLException {
  return this.prepStmt.getMoreResults(current);
 }

 @Override
 public ResultSet getGeneratedKeys() throws SQLException {
  return this.prepStmt.getGeneratedKeys();
 }

 @Override
 public int executeUpdate(String sql, int autoGeneratedKeys) throws SQLException {
  return this.prepStmt.executeUpdate(sql, autoGeneratedKeys);
 }

 @Override
 public int executeUpdate(String sql, int[] columnIndexes) throws SQLException {
  return this.prepStmt.executeUpdate(sql, columnIndexes);
 }

 @Override
 public int executeUpdate(String sql, String[] columnNames) throws SQLException {
  return this.prepStmt.executeUpdate(sql, columnNames);
 }

 @Override
 public boolean execute(String sql, int autoGeneratedKeys) throws SQLException {
  return this.prepStmt.execute(sql, autoGeneratedKeys);
 }

 @Override
 public boolean execute(String sql, int[] columnIndexes) throws SQLException {
  return this.prepStmt.execute(sql, columnIndexes);
 }

 @Override
 public boolean execute(String sql, String[] columnNames) throws SQLException {
  return this.prepStmt.execute(sql, columnNames);
 }

 @Override
 public int getResultSetHoldability() throws SQLException {
  return this.prepStmt.getResultSetHoldability();
 }

 @Override
 public boolean isClosed() throws SQLException {
  return this.prepStmt.isClosed();
 }

 @Override
 public void setPoolable(boolean poolable) throws SQLException {
  this.prepStmt.setPoolable(poolable);
 }

 @Override
 public boolean isPoolable() throws SQLException {
  return this.prepStmt.isPoolable();
 }

 @Override
 public <T> T unwrap(Class<T> iface) throws SQLException {
  return this.prepStmt.unwrap(iface);
 }

 @Override
 public boolean isWrapperFor(Class<?> iface) throws SQLException {
  return this.prepStmt.isWrapperFor(iface);
 }

 @Override
 public ResultSet executeQuery() throws SQLException {
  return this.prepStmt.executeQuery();
 }

 @Override
 public int executeUpdate() throws SQLException {
  return this.prepStmt.executeUpdate();
 }

 @Override
 public void setNull(int parameterIndex, int sqlType) throws SQLException {
  this.prepStmt.setNull(parameterIndex, sqlType);
  setParameter(parameterIndex, null);
 }

 @Override
 public void setBoolean(int parameterIndex, boolean x) throws SQLException {
  this.prepStmt.setBoolean(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setByte(int parameterIndex, byte x) throws SQLException {
  this.prepStmt.setByte(parameterIndex, x);
  // TODO Add to tree set
 }

 @Override
 public void setShort(int parameterIndex, short x) throws SQLException {
  this.prepStmt.setShort(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setInt(int parameterIndex, int x) throws SQLException {
  this.prepStmt.setInt(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setLong(int parameterIndex, long x) throws SQLException {
  this.prepStmt.setLong(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setFloat(int parameterIndex, float x) throws SQLException {
  this.prepStmt.setFloat(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setDouble(int parameterIndex, double x) throws SQLException {
  this.prepStmt.setDouble(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setBigDecimal(int parameterIndex, BigDecimal x) throws SQLException {
  this.prepStmt.setBigDecimal(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setString(int parameterIndex, String x) throws SQLException {
  this.prepStmt.setString(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setBytes(int parameterIndex, byte[] x) throws SQLException {
  this.prepStmt.setBytes(parameterIndex, x);
  // TODO Add to tree set
 }

 @Override
 public void setDate(int parameterIndex, Date x) throws SQLException {
  this.prepStmt.setDate(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setTime(int parameterIndex, Time x) throws SQLException {
  this.prepStmt.setTime(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setTimestamp(int parameterIndex, Timestamp x) throws SQLException {
  this.prepStmt.setTimestamp(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setAsciiStream(int parameterIndex, InputStream x, int length) throws SQLException {
  this.prepStmt.setAsciiStream(parameterIndex, x, length);
 }

 @SuppressWarnings("deprecation")
 @Override
 public void setUnicodeStream(int parameterIndex, InputStream x, int length) throws SQLException {
  this.prepStmt.setUnicodeStream(parameterIndex, x, length);
 }

 @Override
 public void setBinaryStream(int parameterIndex, InputStream x, int length) throws SQLException {
  this.prepStmt.setBinaryStream(parameterIndex, x, length);
 }

 @Override
 public void clearParameters() throws SQLException {
  this.prepStmt.clearParameters();
 }

 @Override
 public void setObject(int parameterIndex, Object x, int targetSqlType) throws SQLException {
  this.prepStmt.setObject(parameterIndex, x, targetSqlType);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setObject(int parameterIndex, Object x) throws SQLException {
  this.prepStmt.setObject(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public boolean execute() throws SQLException {
  return this.prepStmt.execute();
 }

 @Override
 public void addBatch() throws SQLException {
  this.prepStmt.addBatch();
 }

 @Override
 public void setCharacterStream(int parameterIndex, Reader reader, int length) throws SQLException {
  this.prepStmt.setCharacterStream(parameterIndex, reader, length);
 }

 @Override
 public void setRef(int parameterIndex, Ref x) throws SQLException {
  this.prepStmt.setRef(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setBlob(int parameterIndex, Blob x) throws SQLException {
  this.prepStmt.setBlob(parameterIndex, x);
 }

 @Override
 public void setClob(int parameterIndex, Clob x) throws SQLException {
  this.prepStmt.setClob(parameterIndex, x);
 }

 @Override
 public void setArray(int parameterIndex, Array x) throws SQLException {
  this.prepStmt.setArray(parameterIndex, x);
  // TODO Add to tree set
 }

 @Override
 public ResultSetMetaData getMetaData() throws SQLException {
  return this.prepStmt.getMetaData();
 }

 @Override
 public void setDate(int parameterIndex, Date x, Calendar cal) throws SQLException {
  this.prepStmt.setDate(parameterIndex, x, cal);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setTime(int parameterIndex, Time x, Calendar cal) throws SQLException {
  this.prepStmt.setTime(parameterIndex, x, cal);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setTimestamp(int parameterIndex, Timestamp x, Calendar cal) throws SQLException {
  this.prepStmt.setTimestamp(parameterIndex, x, cal);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setNull(int parameterIndex, int sqlType, String typeName) throws SQLException {
  this.prepStmt.setNull(parameterIndex, sqlType, typeName);
  setParameter(parameterIndex, null);
 }

 @Override
 public void setURL(int parameterIndex, URL x) throws SQLException {
  this.prepStmt.setURL(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public ParameterMetaData getParameterMetaData() throws SQLException {
  return this.prepStmt.getParameterMetaData();
 }

 @Override
 public void setRowId(int parameterIndex, RowId x) throws SQLException {
  this.prepStmt.setRowId(parameterIndex, x);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setNString(int parameterIndex, String value) throws SQLException {
  this.prepStmt.setNString(parameterIndex, value);
  setParameter(parameterIndex, value);
 }

 @Override
 public void setNCharacterStream(int parameterIndex, Reader value, long length) throws SQLException {
  this.prepStmt.setNCharacterStream(parameterIndex, value, length);
 }

 @Override
 public void setNClob(int parameterIndex, NClob value) throws SQLException {
  this.prepStmt.setNClob(parameterIndex, value);
 }

 @Override
 public void setClob(int parameterIndex, Reader reader, long length) throws SQLException {
  this.prepStmt.setClob(parameterIndex, reader, length);
 }

 @Override
 public void setBlob(int parameterIndex, InputStream inputStream, long length) throws SQLException {
  this.prepStmt.setBlob(parameterIndex, inputStream, length);
 }

 @Override
 public void setNClob(int parameterIndex, Reader reader, long length) throws SQLException {
  this.prepStmt.setNClob(parameterIndex, reader, length);
 }

 @Override
 public void setSQLXML(int parameterIndex, SQLXML xmlObject) throws SQLException {
  this.prepStmt.setSQLXML(parameterIndex, xmlObject);
  setParameter(parameterIndex, xmlObject);
 }

 @Override
 public void setObject(int parameterIndex, Object x, int targetSqlType, int scaleOrLength) throws SQLException {
  this.prepStmt.setObject(parameterIndex, x, targetSqlType, scaleOrLength);
  setParameter(parameterIndex, x);
 }

 @Override
 public void setAsciiStream(int parameterIndex, InputStream x, long length) throws SQLException {
  this.prepStmt.setAsciiStream(parameterIndex, x, length);
 }

 @Override
 public void setBinaryStream(int parameterIndex, InputStream x, long length) throws SQLException {
  this.prepStmt.setBinaryStream(parameterIndex, x, length);
 }

 @Override
 public void setCharacterStream(int parameterIndex, Reader reader, long length) throws SQLException {
  this.prepStmt.setCharacterStream(parameterIndex, reader, length);
 }

 @Override
 public void setAsciiStream(int parameterIndex, InputStream x) throws SQLException {
  this.prepStmt.setAsciiStream(parameterIndex, x);
  // TODO Add to tree set
 }

 @Override
 public void setBinaryStream(int parameterIndex, InputStream x) throws SQLException {
  this.prepStmt.setBinaryStream(parameterIndex, x);
 }

 @Override
 public void setCharacterStream(int parameterIndex, Reader reader) throws SQLException {
  this.prepStmt.setCharacterStream(parameterIndex, reader);
 }

 @Override
 public void setNCharacterStream(int parameterIndex, Reader value) throws SQLException {
  this.prepStmt.setNCharacterStream(parameterIndex, value);
 }

 @Override
 public void setClob(int parameterIndex, Reader reader) throws SQLException {
  this.prepStmt.setClob(parameterIndex, reader);
  // TODO Add to tree set
 }

 @Override
 public void setBlob(int parameterIndex, InputStream inputStream) throws SQLException {
  this.prepStmt.setBlob(parameterIndex, inputStream);
 }

 @Override
 public void setNClob(int parameterIndex, Reader reader) throws SQLException {
  this.prepStmt.setNClob(parameterIndex, reader);
 }

}

I would assume it's possible to place a proxy between the DB and your app then observe the communication. I'm not familiar with what software you would use to do this.