用Java实现数据库应用系统.doc

我们在做信息系统的时候，都要访问数据库，我最近接手一个项目，项目组决定使用Java编写，我负责数据层的设计和编码，为了提高代码的重用性和提高项目的开发效率。我们开发了一个通用的数据库连接和完成基本操作的类库，个人认为这个类在做MIS系统时还是有一定的价值，所以总结出来，介绍给大家。 　　连接工厂，实现了DataSource接口 package skydev.modules.data; import java.sql.*; import javax.sql.DataSource; import java.io.PrintWriter; public class ConnectionFactory implements DataSource { private String userName; private String password; private String driverName; private String url; private java.sql.Connection connection; /** * 根据设置的连接参数创建一个新的连接实例 * @return */ private Connection getNewConnection() { try { this.connection.close(); //试图关闭连接 } finally { this.connection = null; //释放连接 try { Class.forName(this.driverName); //加载驱动程序 //DriverManager.registerDriver(driver); try { this.connection = DriverManager.getConnection(this.url, this.userName, this.p assword); } catch (SQLException e) { throw e; } } finally { return this.connection; //返回新建立的连接 } } } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getDriverName() { return driverName; } public void setDriverName(String driverName) { this.driverName = driverName; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public java.sql.Connection getConnection() { if (connection != null) { try { if (connection.isClosed()) { connection = null; getNewConnection(); } } catch (SQLException ex) { } } if (connection == null) { //没有设置连接则创建一个连接 getNewConnection(); } return connection; } public Connection getConnection(String userName, String password) throws SQLException { this.setUserName(userName); this.setPassword(password); return getConnection(); } public PrintWriter getLogWriter() { return null; } public void setLogWriter(PrintWriter printW