@Bean
ItemWriter<Event> writer() throws SQLException {
    return new CustomJdbcBatchDataWriter();
}

@Bean
public TaskExecutor taskExecutor(){
    SimpleAsyncTaskExecutor asyncTaskExecutor=new SimpleAsyncTaskExecutor("spring_batch");
    asyncTaskExecutor.setConcurrencyLimit(threadsAmount);
    return asyncTaskExecutor;
}

@Bean
public Job importUserJob(JobCompletionNotificationListener listener) throws Exception {
    return jobBuilderFactory.get("importUserJob")
            .incrementer(new RunIdIncrementer())
            .listener(listener)
            .flow(step1())
            .end()
            .build();
}

@Bean
public Step step1() throws Exception {
    return stepBuilderFactory.get("step1")
            .<Event, Event>chunk(chunkSize)
            .reader(reader())
            .processor(processor())
            .writer(writer())
            .taskExecutor(taskExecutor())
            .build();
}

@Override
public void write(List<? extends Event> items) throws Exception {
try (
    Connection connection = DriverManager.getConnection(
            "jdbc:mysql://localhost:3306/batch?useSSL=false&useServerPrepStmts=false&rewriteBatchedStatements=true",
            "root", "123123") ) {
    connection.setAutoCommit(false);


    String sql = "INSERT INTO events VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
    PreparedStatement ps = connection.prepareStatement(sql);

    for (Event p : items) {
        try {
            ps.setString(1, p.getId());
       //Setting rest of data into prepared statement
       ...
            ps.addBatch();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    ps.executeBatch();
    connection.commit();
}
}