نمط السجل النشط

Part part = new Part ( "Sample part" , 123.45 );

الجزء ب = أجزاء . دفق () . تصفية ( p -> "علبة التروس" . يساوي ( p . اسم ())) . البحث عن أول () . أو وإلا ( لا شيء )؛

package org.wikipedia.examples ;استيراد java.sql.Connection ؛ استيراد java.sql.DriverManager ؛ استيراد java.sql.PreparedStatement ؛ استيراد java.sql.ResultSet ؛ استيراد java.sql.SQLException ؛ استيراد java.sql.Statement ؛public class User { private int id ; private String name ; private String email ;public User ( String name , String email ) { this . name = name ; this . email = email ; }public int getId () { return id ; }public void setId ( int id ) { this . id = id ; }public String getName () { return name ; }public void setName ( String name ) { this . name = name ; }public String getEmail () { return email ; }public void setEmail ( String email ) { this . email = email ; }public void save ( ) { try ( Connection conn = DriverManager.getConnection ( " jdbc : mysql ://localhost:3306/mydb" , " user " , " password " ) ) { if ( this.id == 0 ) { String sql = " INSERT INTO users ( name , email) VALUES (?, ? ) " ; try ( PreparedStatement stmt = conn.preparedStatement ( sql , Statement.RETURN_GENERATED_KEYS ) ) { stmt.setString ( 1 , this.name ) ; stmt.setString ( 2 , this.email ) ; stmt.executeUpdate ( ) ; ResultSet rs = stmt.getGeneratedKeys ( ) ; if ( rs.next ( ) ) { this.id = rs.getInt ( 1 ) ; } } } else { String sql = "UPDATE users SET name = ?, email = ? WHERE id = ?" ; try ( PreparedStatement stmt = conn . prepareStatement ( sql )) { stmt . setString ( 1 , this . name ); stmt . setString ( 2 , this . email ); stmt . setInt ( 3 , this . id ); stmt . executeUpdate (); } } } catch ( SQLException e ) { System . err . printf ( "حدث خطأ SQL: %s%n" , e .getMessage ()); e.printStackTrace ( ) ; } }public static User find ( int id ) { try ( Connection conn = DriverManager.getConnection ( " jdbc :mysql://localhost:3306/mydb" , " user" , " password" )) { String sql = "SELECT * FROM users WHERE id = ?" ; try ( PreparedStatement stmt = conn.preparedStatement ( sql ) ) { stmt.setInt ( 1 , id ); ResultSet rs = stmt.executeQuery (); if ( rs.next ( ) ) { User user = new User ( rs.getString ( " name " ) , rs.getString ( " email " ) ) ; user.setId ( rs.getInt ( " id " ) ) ; return user ; } } } catch ( SQLException e ) { System.err . printf ( "حدث خطأ SQL: %s%n" , e.getMessage ( )) ; e.printStackTrace ( ) ; } return null ; }public void delete ( ) { try ( Connection conn = DriverManager.getConnection ( "jdbc:mysql://localhost:3306/mydb" , " user " , " password" )) { String sql = "DELETE FROM users WHERE id = ?" ; try ( PreparedStatement stmt = conn.preparedStatement ( sql ) ) { stmt.setInt ( 1 , this.id ) ; stmt.executeUpdate ( ) ; } } catch ( SQLException e ) { System.err.printf ( " حدث خطأ SQL: % s % n " , e.getMessage ( ) ) ; e.printStackTrace ( ) ; } } }