java 使用JDBC链接数据库
作者:bin Statement 和 PreparedStatement之间的关系和区别.
关系:PreparedStatement继承自Statement,都是接口
区别:PreparedStatement可以使用占位符,是预编译的,批处理比Statement效率高
package com.zengbingo.ddns; import java.sql.*; public class DBtest { public static void conn() { String URL = "jdbc:mysql://127.0.0.1:3306/wwj?characterEncoding=utf-8"; String USER = "root"; String PASSWORD = "toot"; // 1.加载驱动程序 try { //验证驱动是否引入 Class.forName("com.mysql.jdbc.Driver"); // 2.获得数据库链接 Connection conn = DriverManager.getConnection(URL, USER, PASSWORD); // 3.通过数据库的连接操作数据库,实现增删改查(使用Statement类) String name = "曾彬"; //预编译 String sql = "select * from `wwj`.`yezhu` where name = ?"; PreparedStatement statement = conn.prepareStatement(sql); statement.setString(1, name); ResultSet rs = statement.executeQuery(); // String sql="select * from userinfo where UserName='"+name+"'"; // Statement statement = conn.createStatement(); // ResultSet rs = statement.executeQuery(sql); // 4.处理数据库的返回结果(使用ResultSet类) while (rs.next()) { System.out.println(rs.getString("name") + " " + rs.getString("number")); } // 关闭资源 conn.close(); rs.close(); statement.close(); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } } public static void main(String[] args) { conn(); } }