How to get the self-increasing id in jdbc?

package JDBC;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestJDBC {
	public static void main(String[] args) {
		
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace ();
		}
		//When building the table hero, set the id attribute auto_increment primary key   
		//This location id is set to null or 0 to automatically increase
		String sql = "insert into hero values(0,?,?)";
		try (
				Connection c = DriverManager.getConnection(
						"jdbc:mysql://127.0.0.1:3306/Hero?characterEncoding=UTF-8",
						"root",
						"123"); //Set the Statement.RETURN_GENERATED_KEYS parameter
				PreparedStatement ps = c.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
				)
			{	
				// set properties
				ps.setString(1, "Li Bai");
				ps.setInt(2, 25);
				//Execute sql
				ps.execute();
				
								//getGeneratedKeys() gets the result set
				ResultSet rs = ps.getGeneratedKeys();
				while(rs.next()) {
					//get the value of id
					int id = rs.getInt(1);
					System.out.println(id);
				}
		} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace ();
		}
	}
}