Java-编写一个jdbc操作类

1.通过读取文件配置

package 数据库操作类;  
  
  
    /* * Db.java 
    Created 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();  
            }  
        }    
    }