J2SE学习笔记（5）JDBC

JDBC：Java DataBase Connectivity（Java 数据库连接技术），它是将Java与SQL结合且独立于特定的数据库系统的应用程序编程接口（API--它是一种可用于执行SQL语句的Java API，即由一组用Java语言编写的类与接口所组成）。

 

public class FirstConnection ...{

    public static void main(String[] args) ...{
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs  = null;
        try ...{
            // 加载驱动程序 (默认自动注册)
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            // 注册驱动程序
            /**//*
             * Driver driver = new SQLServerDriver();
             * DriverManager.registerDriver(driver);
             */

            String url = "jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=Northwind";
            String username = "sa";
            String password = "sa";
            
            // 获取连接
            conn = DriverManager.getConnection(url, username, password);
            System.out.println(conn);
            // 创建Statement
            stmt = conn.createStatement();
            String sql = "insert into Categories (CategoryName,Description,Picture ) values ('电脑','test','1.jpg')";
            // 执行语句
            //更新操作
            /**//*int count = stmt.executeUpdate(sql);
            System.out.println("受影响的纪录条数:" + count);*/
            //查询操作
            String querySql = "select * from Categories";
            //获取查询结果
            rs = stmt.executeQuery(querySql);
            while(rs.next())...{
                System.out.print(rs.getString(1));
                System.out.print(rs.getString("CategoryName"));
                System.out.println(rs.getString(3));
            }

        } catch (ClassNotFoundException e) ...{
            e.printStackTrace();
            // System.out.println("类驱动程序无法加载："+e.getMessage());
        } catch (SQLException e) ...{

            e.printStackTrace();
        } finally ...{
            //关闭rs
            if (rs != null)
                try ...{
                    rs.close();

                } catch (SQLException e1) ...{

                    System.out.println(e1);
                }
            //关闭stmt
            if (stmt != null)
                try ...{
                    stmt.close();

                } catch (SQLException e1) ...{

                    System.out.println(e1);
                }
            //关闭连接conn    
            if (conn != null)
                try ...{
                    conn.close();
                } catch (SQLException e) ...{
                    e.printStackTrace();
                }

        }

    }

}

 

public class PreparedDemo ...{

    public static void main(String[] args) ...{
        Connection conn = null;
        PreparedStatement ps = null;
        try ...{
            // 加载驱动程序 (默认自动注册)
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
            // 注册驱动程序
            /**//*
             * Driver driver = new SQLServerDriver();
             * DriverManager.registerDriver(driver);
             */

            String url = "jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=Northwind";
            String username = "sa";
            String password = "sa";
            
            // 获取连接
            conn = DriverManager.getConnection(url, username, password);
            System.out.println(conn);
            // 创建prepareStatement
            String sql = "insert into Categories (CategoryName,Description ) values (?,?)";        
            ps = conn.prepareStatement(sql);
            // 给参数负值
            ps.setString(1,"computer");
            ps.setString(2,"computer vvv");
            
            //执行语句
            ps.executeUpdate();
            
        } catch (ClassNotFoundException e) ...{
            e.printStackTrace();
            // System.out.println("类驱动程序无法加载："+e.getMessage());
        } catch (SQLException e) ...{

            e.printStackTrace();
        } finally ...{
            
            //关闭ps
            if (ps != null)
                try ...{
                    ps.close();

                } catch (SQLException e1) ...{

                    System.out.println(e1);
                }
            //关闭连接conn    
            if (conn != null)
                try ...{
                    conn.close();
                } catch (SQLException e) ...{
                    e.printStackTrace();
                }

        }

    }

}