数据库操作类

package 数据库操作类;/* * Db.javaCreated on 2007年8月20日, 上午 8:37*/import java.io.*;import java.sql.*;import java.util.Properties;public class DB {    private String driver;    private String url;    private String user;    private String password;    private Connection conn;    private Statement stm;    private ResultSet rs;    public DB(){        this("DBConf.properties");    }    public DB(String conf) {        loadProperties(conf);        setConn();    }    public Connection getConn(){        return this.conn;    }  //handle the properties file to get the informations for connection    private void loadProperties(String conf){        Properties props = new Properties();        try {            props.load(new FileInputStream(conf));        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        this.driver = props.getProperty("driver");        this.url = props.getProperty("url");        this.user = props.getProperty("user");        this.password = props.getProperty("password");    }    //implement the Connection    private void setConn(){        try {            Class.forName(driver);            this.conn = DriverManager.getConnection(url,user,password);        } catch(ClassNotFoundException classnotfoundexception) {              classnotfoundexception.printStackTrace();            System.err.println("db: " + classnotfoundexception.getMessage());        } catch(SQLException sqlexception) {            System.err.println("db.getconn(): " + sqlexception.getMessage());        }    }       public void doInsert(String sql) {        try {            Statement statement = conn.createStatement();            int i = stm.executeUpdate(sql);        } catch(SQLException sqlexception) {            System.err.println("db.executeInset:" + sqlexception.getMessage());        }    }    public void doDelete(String sql) {        try {            stm = conn.createStatement();            int i = stm.executeUpdate(sql);        } catch(SQLException sqlexception) {            System.err.println("db.executeDelete:" + sqlexception.getMessage());        }    }    public void doUpdate(String sql) {        try {            stm = conn.createStatement();            int i = stm.executeUpdate(sql);        } catch(SQLException sqlexception) {            System.err.println("db.executeUpdate:" + sqlexception.getMessage());        }    }        public ResultSet doSelect(String sql) {        try {            stm = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);            rs = stm.executeQuery(sql);        } catch(SQLException sqlexception) {            System.err.println("db.executeQuery: " + sqlexception.getMessage());        }        return rs;    }    public static void main(String[] args){        try{            DB db = new DB();            Connection conn = db.getConn();            if(conn != null && !conn.isClosed()) {                System.out.println("連結成功");                ResultSet rs = db.doSelect("select * from content");                while(rs.next()){                    System.out.println(rs.getString(1)+":"+rs.getString(2)+":"+rs.getString(3));                  }                rs.close();                conn.close();            }        }catch(SQLException e) {            e.printStackTrace();        }    }  }