JDBC Statment 使用属性池连接数据库
//测试类
插入 删除 更新 基本一致
1 public class TestInsert { 2 public static void main(String[] args) { 3 Connection conn = null; 4 Statement st =null; 5 ResultSet rs =null; 6 try{ 7 conn = JdbcUtils.getConnection(); 8 st = conn.createStatement(); 9 String sql ="insert into users(id,name,password,email,birthday) values(4,'zxy','123456','16033673@qq.com','2002-3-13');"; 10 int i = st.executeUpdate(sql); 11 if(i>0){ 12 System.out.println("插入成功"); 13 } 14 }catch (SQLException e){ 15 e.printStackTrace(); 16 }finally { 17 JdbcUtils.release(conn,st,rs); 18 } 19 } 20 }
查找
1 public class TestSelect { 2 public static void main(String[] args) throws SQLException { 3 Connection conn = null; 4 Statement st = null; 5 ResultSet rs = null; 6 try { 7 conn = JdbcUtils.getConnection(); 8 st = conn.createStatement(); 9 //SQL 10 String sql = "select * from users where id =1"; 11 rs = st.executeQuery(sql); 12 while(rs.next()){ 13 System.out.println(rs.getString("name")); 14 } 15 16 } catch (SQLException e) { 17 e.printStackTrace(); 18 }finally { 19 JdbcUtils.release(conn,st,rs); 20 } 21 } 22 }
注意！ executeQuery 返回的时ResultSet的结果类 sql运行的结果
executeUpdate返回的时一个int类型的数 意思时 受影响的行数
//工具类
1 public class JdbcUtils { 2 private static String driver = null; 3 private static String url = null; 4 private static String username = null; 5 private static String password = null; 6 static { 7 try{ 8 InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties"); 9 Properties properties = new Properties(); 10 properties.load(in); 11 driver = properties.getProperty("driver"); 12 url = properties.getProperty("url"); 13 username = properties.getProperty("username"); 14 password = properties.getProperty("password"); 15 16 //1.加载驱动 17 Class.forName(driver); 18 }catch (Exception e){ 19 e.printStackTrace(); 20 } 21 22 } 23 //获取连接 24 public static Connection getConnection() throws SQLException { 25 return DriverManager.getConnection(url,username,password); 26 } 27 //释放资源 28 public static void release(Connection conn, Statement st, ResultSet rs){ 29 if(rs!=null){ 30 try{ 31 rs.close(); 32 } catch (SQLException e) { 33 e.printStackTrace(); 34 } 35 } 36 if(st!=null){ 37 try { 38 st.close(); 39 } catch (SQLException e) { 40 e.printStackTrace(); 41 } 42 } 43 if(conn!=null){ 44 try { 45 conn.close(); 46 } catch (SQLException e) { 47 e.printStackTrace(); 48 } 49 } 50 51 } 52 53 }
//属性池
1 driver=com.mysql.cj.jdbc.Driver 2 url=jdbc:mysql://localhost:3306/jdbcstudy?serverTimezone=GMT%2B8 3 username=root 4 password=123456789
