JDBC 连接数据实例
1、JDBC连接数据库实例 try{}catch{}finally{}

package com.terac.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.Statement;public class DBTest {public static void main(String[] args) {try {String user = "user";String password = "password";String driver = "COM.ibm.db2.jdbc.net.DB2Driver";//"oracle.jdbc.driver.OracleDriver";//"com.mysql.jdbc.Driver";//"org.postgresql.Driver";String url = "jdbc:db2://localhost/a";//"jdbc:oracle:thin:@localhost:1521:a";//"jdbc:mysql://localhost/a";//"jdbc:postgresql://localhost:5740/a";String sql = "SELECT current timestamp FROM sysibm.sysdummy1";//"SELECT sysdate FROM dual";//"SELECT now()";//"SELECT current_timestamp";Class.forName(driver).newInstance();Connection conn = DriverManager.getConnection(url, user, password);Statement stmt = conn.createStatement();ResultSet rs = stmt.executeQuery(sql);while (rs.next()) {System.out.println(rs.getString(1));}} catch (Exception e) {e.printStackTrace();} finally {if (stmt != null) {try {stmt.close();} catch (SQLException e) {logger.error(e.getMessage(), e);}stmt = null;}if (conn != null) {try {conn.close();} catch (SQLException e) {logger.error(e.getMessage(), e);}conn = null;}}}}