Java与JavaEE实习指导书v0.5(19)

public class Test { public static void main(String[] args) { Connection connection; try { Class.forName("org.hsqldb.jdbcDriver"); connection = DriverManager.getConnection( "jdbc:hsqldb:hsql://localhost/xdb", "sa", ""); } catch (Exception e) { e.printStackTrace(); return; } // --- Set up the database --- try { // Create a Statement object to execute the queries on, Statement statement = connection.createStatement(); ResultSet result; System.out.println("-- Creating Tables --"); statement.executeUpdate(" drop TABLE Person "); // Create a Person table, statement.executeUpdate(" CREATE TABLE Person ( " + " name VARCHAR(100) PRIMARY KEY, " + " age INTEGER, " + " lives_in VARCHAR(100) ) "); System.out.println("-- Inserting Data --"); statement.addBatch("INSERT INTO Person ( name, age, lives_in ) VALUES " + " ( 'Robert Bellamy', 24, 'England' ); "); statement.addBatch("INSERT INTO Person ( name, age, lives_in ) VALUES " + " ( 'Grayham Downer', null, 'Africa' );"); statement.addBatch(" INSERT INTO Person ( name, age, lives_in ) VALUES " + " ( 'Timothy French', 24, 'Africa' ); "); statement.addBatch(" INSERT INTO Person ( name, age, lives_in ) VALUES " + " ( 'Butch Fad', 53, 'USA' ); "); statement.addBatch(" INSERT INTO Person ( name, age, lives_in ) VALUES " + " ( 'Judith Brown', 34, 'Africa' ) "); statement.executeBatch(); System.out.println("-- SQL queries --"); // get average age of the people result = statement.executeQuery("SELECT AVG(age) FROM Person"); if (result.next()) {