cloudlogcustomernames.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

import java.util.*;
import java.sql.*;

public class CloudLogCustomerNames {

  private static final String ORACLE_JDBC_DRIVER_CLASS_NAME = 
    "COM.cloudscape.core.JDBCDriver";
  private static final String ORACLE_DEMO_DB_URL = 
    "jdbc:cloudscape:c:/wrox/database/Wrox4370.db";

  private static final String ORACLE_DEMO_DB_USERID_PROPERTY = "user";
  private static final String ORACLE_DEMO_DB_USERID = "beg";

  private static final String ORACLE_DEMO_DB_PASSWORD_PROPERTY = "password";
  private static final String ORACLE_DEMO_DB_PASSWORD = "java";
  private static final String SQL_QUERY = "select CUSTOMERFIRSTNAME from CUSTOMERS";

  private Connection getConnection() throws Exception {

    Class.forName(ORACLE_JDBC_DRIVER_CLASS_NAME).newInstance();

    Properties connectionProperties = new Properties();

    connectionProperties.put(ORACLE_DEMO_DB_USERID_PROPERTY, 
                             ORACLE_DEMO_DB_USERID);

    connectionProperties.put(ORACLE_DEMO_DB_PASSWORD_PROPERTY, 
                             ORACLE_DEMO_DB_PASSWORD);

    return DriverManager.getConnection(ORACLE_DEMO_DB_URL, 
                                       connectionProperties);
  } 

  private void printResultSet(ResultSet resultSet) {

    System.out.println("Customer Name");
    System.out.println("-------------");

    try {
      while (resultSet.next()) {

        System.out.println(resultSet.getString(1));
      } 
    } catch (SQLException e) {

      System.err.println("Error retrieving result set rows from '" 
                         + resultSet + "', caught exception " + e);
      e.printStackTrace();
    } 
  } 

  private void readCustomers(Connection connection) {
    Statement statement = null;
    ResultSet resultSet = null;

    try {
      statement = connection.createStatement();

      System.out.println("Opened JDBC Statement " + statement 
                         + " at LogCustomerNames.readCustomers()");

      System.out.println("Executing SQL Query: '" + SQL_QUERY 
                         + "' on database " + ORACLE_DEMO_DB_URL);

      long queryStartTime = System.currentTimeMillis();

      resultSet = statement.executeQuery(SQL_QUERY);

      long queryTime = System.currentTimeMillis() - queryStartTime;
      System.out.println("SQL Query: '" + SQL_QUERY + "' took " + queryTime 
                         + " milliseconds to execute");

      System.out.println("Retrieved JDBC ResultSet " + resultSet 
                         + " at LogCustomerNames.readCustomers()");

      printResultSet(resultSet);

    } catch (SQLException e) {

      System.err.println("Error querying database '" + ORACLE_DEMO_DB_URL 
                         + "', caught exception " + e);
      e.printStackTrace();
    } 
    finally {

      if (resultSet != null) {
        try {
          resultSet.close();

          System.out.println("Closed JDBC ResultSet " + resultSet);
        } catch (SQLException e) {

          System.err.println("Error closing result set " + resultSet 
                             + ", caught exception " + e);
          e.printStackTrace();
        } 
      } 

      if (statement != null) {
        try {
          statement.close();

          System.out.println("Closed JDBC Statement " + statement);
        } catch (SQLException e) {


          System.err.println("Error closing statement " + statement 
                             + ", caught exception " + e);
          e.printStackTrace();
        } 
      } 
    } 
  } 

  public void runQuery() {
    Connection databaseConnection = null;

    try {

      databaseConnection = getConnection();

      System.out.println("Opened JDBC Connection " + databaseConnection 
                         + " at LogCustomerNames.runQuery()");

      readCustomers(databaseConnection);

    } catch (Exception e) {

      System.err.println("Error opening connection to database '" 
                         + ORACLE_DEMO_DB_URL + "', caught exception " + e);
      e.printStackTrace();
    } 
    finally {

      if (databaseConnection != null) {
        try {
          databaseConnection.close();

          System.out.println("Closed JDBC Connection " 
                             + databaseConnection);
        } catch (SQLException e) {

          System.err.println("Error closing connection to database '" 
                             + ORACLE_DEMO_DB_URL + "', caught exception " 
                             + e);
          e.printStackTrace();
        } 

      } 
    } 
  } 

  public static void main(String[] args) {
    CloudLogCustomerNames logCustomerNames = new CloudLogCustomerNames();

    logCustomerNames.runQuery();
  } 
}