通过资源文件获取连接的JDBC数据库连接类
连接数据库的工具类：package com.zlk.dao;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import com.zlk.util.EnvironmentConfig;public class DBConnection {private static DBConnection conn = null; private static String DB_PROPERTIES="/com/zlk/config/db.properties";private static EnvironmentConfig ec = EnvironmentConfig.getInstance();private static String DRIVER_CLASS_NAME = ec.getPropertyValue(DB_PROPERTIES, "db.jdbc.driverClassName");private static String URL = ec.getPropertyValue(DB_PROPERTIES, "db.jdbc.url");private static String USERNAME = ec.getPropertyValue(DB_PROPERTIES, "db.jdbc.username");private static String PASSWORD= ec.getPropertyValue(DB_PROPERTIES, "db.jdbc.password");/** * 私有构造函数，加载连接驱动 */private DBConnection(){try {Class.forName(DRIVER_CLASS_NAME);} catch (ClassNotFoundException e) {// TODO Auto-generated catch blockSystem.out.println("连接驱动未找到..............");e.printStackTrace();}}/** * 实例化类对象 */public static DBConnection getInstance(){if(conn == null){return new DBConnection();}return conn;}/** * 创建数据库连接 */public Connection getConnection() throws SQLException{return DriverManager.getConnection(URL,USERNAME,PASSWORD);}/** * 释放资源 */ public void release(Connection conn, PreparedStatement ps,ResultSet rs) { if (rs != null)try {rs.close();} catch (SQLException e) {e.printStackTrace();} if (ps != null) try {ps.close();} catch (SQLException e) {e.printStackTrace();} if (conn!= null)try {conn.close();} catch (SQLException e) {e.printStackTrace();} } /** * 释放资源 */ public void release(Object obj) { if (obj instanceof Connection) { Connection conn = (Connection) obj; if (conn != null) try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } if (obj instanceof PreparedStatement) { PreparedStatement ps = (PreparedStatement) obj; if (ps != null) try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } } if (obj instanceof ResultSet) { ResultSet rs = (ResultSet) obj; if (rs != null) try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } } }
读取资源文件的工具类：
package com.zlk.util;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.util.Hashtable;import java.util.Properties;/** * java 读取配置（属性）文件 * @author Billows.Van * billows.van@gmail.com */public class EnvironmentConfig { static EnvironmentConfig ec;// 创建对象ec private static Hashtable<String, Properties> register = new Hashtable<String, Properties>();// 静态对象初始化[在其它对象之前] private EnvironmentConfig() { super(); } /** * 取得EnvironmentConfig的一个实例 */ public static EnvironmentConfig getInstance() { if (ec == null) ec = new EnvironmentConfig();// 创建EnvironmentConfig对象 return ec;// 返回EnvironmentConfig对象 } /** * 读取配置文件 */ public Properties getProperties(String fileName) {// 传递配置文件路径 InputStream is = null;// 定义输入流is Properties p = null; try { p = (Properties) register.get(fileName);// 将fileName存于一个HashTable /** * 如果为空就尝试输入进文件 */ if (p == null) { try { is = new FileInputStream(fileName);// 创建输入流 } catch (Exception e) { if (fileName.startsWith("/")) // 用getResourceAsStream()方法用于定位并打开外部文件。 is = EnvironmentConfig.class.getResourceAsStream(fileName); else is = EnvironmentConfig.class.getResourceAsStream("/"+fileName); } p = new Properties(); p.load(is);// 加载输入流 register.put(fileName, p);// 将其存放于HashTable缓存 is.close();// 关闭输入流 } } catch (Exception e) { e.printStackTrace(System.out); } return p;// 返回Properties对象 } /** * 此处插入方法描述。 */ public String getPropertyValue(String fileName, String strKey) { Properties p = getProperties(fileName); try { return (String) p.getProperty(strKey); } catch (Exception e) { e.printStackTrace(System.out); } return null; } /** * 修改配置文件的值 */ public void setPropertyValue(String fileName,String strKey,String StrValue){ Properties p = getProperties(fileName); OutputStream os = null; try { if(p!=null){File file = new File(this.getClass().getResource("/").getPath().replace("%20", " "));//找到指定目录，其中路径中的“%20”用空格代替file = new File(file.getPath()+fileName);//找到指定文件 os = new FileOutputStream(file);p.setProperty(strKey, StrValue);p.store(os, "Last Modified"); }} catch (Exception e) {e.printStackTrace(System.out); }finally{try {os.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}} } /** * 重载资源文件 */ public void reloadProterties(){ this.register.clear(); }}
资源文件：
db.jdbc.driverClassName=com.microsoft.jdbc.sqlserver.SQLServerDriverdb.jdbc.url=jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=testdb.jdbc.username=sadb.jdbc.password=sa
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