With this example we are going to demonstrate how to execute a batch statement in Java. In particular we are going to insert 10 rows of data to a table. In short, to execute a batch statement you should:
- Load the JDBC driver, using the
forName(String className)API method of the Class. In this example we use the MySQL JDBC driver. - Create a Connection to the database. Invoke the
getConnection(String url, String user, String password)API method of the DriverManager to create the connection. - Disable auto-commit, with the
setAutoCommit(boolean autoCommit)API method, so that SQL statements are grouped into transactions that are terminated by a call to either the method commit or the method rollback. - Create a PreparedStatement object, using the
prepareStatement(String sql)API method of the Connection in order to send the parameterized SQL statement to the database. - For each one of the 10 rows invoke the
setString(int parameterIndex, String x)andaddBatch()API methods of the PreparedStatement, in order to set the parameters in the String value of each row and then add the row to the batch. - Invoke the
executeBatch()in order to execute the batch, which will return an array of update counts. - If there are no errors commit, with the
commit()API method. - If there is a BatchUpdateException, something is wrong with the updated rows. So for each one of them, check if the batch statement was executed successfully, but no count of the number of rows it affected is available ( SUCCESS_NO_INFO ). Check also if any error occured while executing a batch statement ( EXECUTE_FAILED ). If an error has occured, rollback, with the
rollback()API method.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
import java.sql.BatchUpdateException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
public class BatchInsert {
public static void main(String[] args) {
Connection connection = null;
try {
// Load the MySQL JDBC driver
String driverName = "com.mysql.jdbc.Driver";
Class.forName(driverName);
// Create a connection to the database
String serverName = "localhost";
String schema = "test";
String url = "jdbc:mysql://" + serverName + "/" + schema;
String username = "username";
String password = "password";
connection = DriverManager.getConnection(url, username, password);
System.out.println("Successfully Connected to the database!");
} catch (ClassNotFoundException e) {
System.out.println("Could not find the database driver " + e.getMessage());
} catch (SQLException e) {
System.out.println("Could not connect to the database " + e.getMessage());
}
try {
// Disable auto-commit
connection.setAutoCommit(false);
// Create a prepared statement
PreparedStatement statement = connection.prepareStatement("INSERT INTO test_table VALUES(?)");
// Insert 10 rows of data
for (int i=0; i<10; i++) {
statement.setString(1, "test_value_"+i);
statement.addBatch();
}
/*
* Execute the batch and get an array containing the result code for every
* individual statement execution. For every successful statement execution
* the number of rows affected by the specific statement is returned. If the
* number of affected rows is not available a Statement.SUCCESS_NO_INFO is
* returned. If a statement execution fails then a BatchUpdateException is thrown.
* Nevertheless some databases will continue to execute statements after one fails
* returning Statement.EXECUTE_FAILED for every failed statement execution. If so,
* updateCounts will contain results for all batched statements; else updateCounts
* will contain results for the statements that where executed up until the first one
* that failed
*/
int[] updateCounts = statement.executeBatch();
// Since there were no errors, commit
connection.commit();
System.out.println("Successfully added 10 rows to the database");
} catch (BatchUpdateException e) {
// Not all of the statements were successfully executed
int[] updateCounts = e.getUpdateCounts();
for (int i=0; i<updateCounts.length; i++) {
if (updateCounts[i] >= 0) {
// Successfully executed; the number represents number of affected rows
} else if (updateCounts[i] == Statement.SUCCESS_NO_INFO) {
// Successfully executed; number of affected rows not available
} else if (updateCounts[i] == Statement.EXECUTE_FAILED) {
// Failed to execute
}
}
// We can commit the successfully executed statements or rollback the entire batch - here we rollback
try {
connection.rollback();
} catch (SQLException e1) {
System.out.println("Could not rollback transaction " + e1.getMessage());
}
} catch (SQLException e) {
System.out.println("Could not execute statement " + e.getMessage());
}
}
}
Example Output:
Successfully Connected to the database!
Successfully added 10 rows to the database
This was an example of how to execute a batch statement in Java.
