Mysql實(shí)戰(zhàn)練習(xí)之簡單圖書管理系統(tǒng)
一、梳理功能
1.能夠表示書籍信息,針對每本書來說,序號,書名,作者,價格,類型。
2.能夠表示用戶信息,普通用戶,管理員。
3.支持的操作:
- 對于普通用戶:查看書籍列表,查詢指定書籍,借書還書。
- 對于 管理員:查看書籍列表,新增刪除書籍。
二、準(zhǔn)備數(shù)據(jù)庫
創(chuàng)建用戶表和書籍表
create database if not exists java100_bookmanager; use java100_bookmanager; drop table if exists book; //設(shè)置id為自增主鍵 create table book(id int primary key auto_increment,name varchar(20),author varchar(20),price int,type varchar(20),isBorrowed int); drop table if exists user; //同樣設(shè)置 userid為自增主鍵并且用戶名字不重復(fù) create table user( userId int primary key auto_increment, username varchar(20) unique, password varchar(20), isAdmin int ); -- 插入一些書籍 insert into book values(null,'西游記','吳承恩',10000,'古典小說',0); insert into book values(null,'三國演義','羅貫中',10000,'古典小說',0); insert into book values(null,'水滸傳','施耐庵',10000,'古典小說',0); insert into book values(null,'金瓶梅','蘭陵笑笑生',10000,'古典小說',0); --插入一些用戶 insert into user values(null,'admin','123',1); insert into user values(null,'zhangsan','123',0);
三、構(gòu)造和數(shù)據(jù)庫相關(guān)的實(shí)體類
書籍
public class Books { private int bookId;//書籍編號 private String name;//書名 private String author;//作者 private int price;//價格 private String type;//類型 private boolean isBorrowed;//是否被借閱 //set get方法 public int getBookId() { return bookId; } public void setBookId(int bookId) { this.bookId = bookId; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } public String getType() { return type; } public void setType(String type) { this.type = type; } public boolean isBorrowed() { return isBorrowed; } public void setBorrowed(boolean borrowed) { isBorrowed = borrowed; } @Override public String toString() { return "Book{" + "bookId=" + bookId + ", name='" + name + '\'' + ", author='" + author + '\'' + ", price=" + price + ", type='" + type + '\'' + ", isBorrowed=" + isBorrowed + '}'; }
用戶
有兩種用戶,一種為普通用戶,另一種為管理員,管理員和普通用戶看到的menu不同,管理員和普通 用戶的類方法也不同
先定義一個抽象類User 讓普通用戶NoramlUser和管理員類Admin來繼承User類
abstract public class user { private int userId; private String userName; private String passWord; IOperation[] operations;//方法數(shù)組,表示user類所包含的方法 abstract int menu();//子類要重寫menu方法,因?yàn)閮蓚€子類看到的menu不同 public void doOperation(int choice){//此方法來執(zhí)行一些操作,如借書還書等 operations[choice].work(); } public int getUserId() { return userId; } public void setUserId(int userId) { this.userId = userId; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassWord() { return passWord; } public void setPassWord(String passWord) { this.passWord = passWord; } @Override public String toString() { return "user{" + "userId=" + userId + ", userName='" + userName + '\'' + ", passWord='" + passWord + '\'' + '}'; } }
NormalUser類
public class NormalUser extends user{ public NormalUser(){ this.operations=new IOperation[]{//之后單獨(dú)開辟一個包,包里存儲和實(shí)現(xiàn)這些方法 new ExitOperation(),//退出系統(tǒng) new DisplayOperation(),//查看書籍列表 new FindOperation(),//查找書籍 new BorrowOperation(),//借閱書籍 new ReturnOperation(),//還書 }; } @Override public int menu() {//重寫父類menu方法 System.out.println("========================"); System.out.println("歡迎您,"+this.getUserName()+"!"); System.out.println("1.查看書籍列表"); System.out.println("2.查找指定書籍"); System.out.println("3.借閱書籍"); System.out.println("4.歸還書籍"); System.out.println("0.退出系統(tǒng)"); System.out.println("========================"); System.out.println("請輸入選項(xiàng)"); Scanner sc=new Scanner(System.in); int choice=sc.nextInt(); return choice; } }
Admin類
public class Admin extends user { public Admin(){ this.operations=new IOperation[]{ new ExitOperation(),//退出系統(tǒng) new DisplayOperation(),//查看書籍列表 new FindOperation(),//查找書籍 new AddOperation(),//添加書籍 new DelOperation(),//刪除書籍 }; } @Override public int menu() { System.out.println("========================"); System.out.println("歡迎您,"+this.getUserName()+"您是管理員!"); System.out.println("1.查看書籍列表"); System.out.println("2.查找指定書籍"); System.out.println("3.新增書籍"); System.out.println("4.刪除書籍"); System.out.println("0.退出系統(tǒng)"); System.out.println("========================"); System.out.println("請輸入選項(xiàng)"); Scanner sc=new Scanner(System.in); int choice=sc.nextInt(); return choice; } }
四、封裝數(shù)據(jù)庫相關(guān)操作
- 1.先把數(shù)據(jù)庫鏈接的操作封裝好
- 2.再把針對書籍表的增刪查改操作封裝好
- 3.再把針對用戶表的操作封裝好
數(shù)據(jù)庫鏈接操作
//在這里封裝數(shù)據(jù)庫的連接操作 public class DBUtil { //設(shè)置url 賬號密碼 根據(jù)個人設(shè)置 private static final String URL="jdbc:mysql://127.0.0.1:3306/java100_bookmanager?characterEncoding=utf8&&useSSL=false"; private static final String USERNAME="root"; private static final String PASSWORD="q986681563"; //餓漢模式 //類加載階段就會調(diào)用靜態(tài)代碼塊進(jìn)行實(shí)例化 /*private static DataSource dataSource=new MysqlDataSource(); static{ ((MysqlDataSource)dataSource).setUrl(URL); ((MysqlDataSource)dataSource).setUser(USERNAME); ((MysqlDataSource)dataSource).setPassword(PASSWORD); }*/ //懶漢模式 //只有首次調(diào)用getDataSource方法 才會實(shí)例化 private static DataSource dataSource=null; public static DataSource getDataSource(){ if(dataSource==null){ dataSource=new MysqlDataSource(); ((MysqlDataSource)dataSource).setUrl(URL); ((MysqlDataSource)dataSource).setUser(USERNAME); ((MysqlDataSource)dataSource).setPassword(PASSWORD); } return dataSource; } public static Connection getConnection() throws SQLException { return getDataSource().getConnection(); } public static void close(ResultSet resultSet, PreparedStatement statement,Connection connection){//釋放資源 //注釋掉的方式更安全 /*if(resultSet!=null){ try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } } if(statement!=null){ try { statement.close(); } catch (SQLException e) { e.printStackTrace(); } } if(connection!=null){ try { connection.close(); } catch (SQLException e) { e.printStackTrace(); } }*/ try { if(resultSet!=null) resultSet.close(); if(statement!=null) statement.close(); if(connection!=null) connection.close(); } catch (SQLException e) { e.printStackTrace(); } } }
針對書籍表操作
//DAO Data Access Object 數(shù)據(jù)訪問對象 public class BookDAO { //1.新增書籍 public boolean add(Books book){ Connection connection=null; PreparedStatement statement=null; try { connection= DBUtil.getConnection(); String sql="insert into book values(null,?,?,?,?,?)"; statement=connection.prepareStatement(sql); statement.setString(1,book.getName()); statement.setString(2,book.getAuthor()); statement.setInt(3,book.getPrice()); statement.setString(4,book.getType()); statement.setInt(5,book.isBorrowed()?1:0); int ret=statement.executeUpdate(); if(ret!=1) return false; return true; } catch (SQLException e) { e.printStackTrace(); }finally { DBUtil.close(null,statement,connection); } return false; } //2.查看所有書籍 public List<Books> selectAll(){ List<Books> list=new ArrayList<>(); Connection connection=null; PreparedStatement statement=null; ResultSet resultSet=null; try { connection=DBUtil.getConnection(); String sql="select*from book"; statement=connection.prepareStatement(sql); resultSet=statement.executeQuery(); while(resultSet.next()){ Books book=new Books(); book.setBookId(resultSet.getInt("id")); book.setName(resultSet.getString("name")); book.setAuthor(resultSet.getString("author")); book.setPrice(resultSet.getInt("price")); book.setType(resultSet.getString("type")); book.setBorrowed(resultSet.getInt("isBorrowed")==1); list.add(book); } } catch (SQLException e) { e.printStackTrace(); }finally { DBUtil.close(resultSet,statement,connection); } return list; } //3.根據(jù)名字找書籍 public List<Books> selectByName(String name) { List<Books> list=new ArrayList<>(); Connection connection=null; PreparedStatement statement=null; ResultSet resultSet=null; try { connection=DBUtil.getConnection(); String sql="select* from book where name=?"; statement=connection.prepareStatement(sql); statement.setString(1,name); resultSet=statement.executeQuery(); while(resultSet.next()){ Books book=new Books(); book.setBookId(resultSet.getInt("Id")); book.setName(resultSet.getString("name")); book.setAuthor(resultSet.getString("author")); book.setType(resultSet.getString("type")); book.setPrice(resultSet.getInt("price")); book.setBorrowed(resultSet.getInt("isBorrowed")==1); list.add(book); } } catch (SQLException e) { e.printStackTrace(); }finally { DBUtil.close(resultSet,statement,connection); } return list; } //4.刪除書籍 public boolean delete(int bookId){ Connection connection=null; PreparedStatement statement=null; try { connection=DBUtil.getConnection(); String sql="delete from book where id=?"; statement=connection.prepareStatement(sql); statement.setInt(1,bookId); int ret=statement.executeUpdate(); if(ret!=1) return false; return true; } catch (SQLException e) { e.printStackTrace(); }finally { DBUtil.close(null,statement,connection); } return false; } //5.借書 public boolean borrowBook(int bookId){ Connection connection=null; PreparedStatement statement=null; PreparedStatement statement2=null; ResultSet resultSet=null; try { connection=DBUtil.getConnection(); String sql="select * from book where id=?"; statement=connection.prepareStatement(sql); statement.setInt(1,bookId); resultSet=statement.executeQuery(); if(resultSet.next()){ boolean isBorrowed=(resultSet.getInt("isBorrowed")==1); if(isBorrowed){ System.out.println("書已借出,無法再次借出! bookId="+bookId); return false; } }else{ System.out.println("書不存在 bookId="+bookId); return false; } sql="update book set isBorrowed=1 where id=?"; statement2=connection.prepareStatement(sql); statement2.setInt(1,bookId); int ret = statement2.executeUpdate(); if(ret!=1) { System.out.println("借閱失敗"); return false; } System.out.println("借閱成功"); return true; } catch (SQLException e) { e.printStackTrace(); }finally { if(resultSet!=null) { try { connection.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(statement!=null) { try { statement.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(statement2!=null) { try { statement2.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(connection!=null){ try { connection.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } } return false; } //6.歸還 public boolean returnBook(int bookId){ Connection connection=null; PreparedStatement statement=null; PreparedStatement statement2=null; ResultSet resultSet=null; try { connection=DBUtil.getConnection(); String sql="select* from book where id=?"; statement=connection.prepareStatement(sql); statement.setInt(1,bookId); resultSet= statement.executeQuery(); if(resultSet.next()){ boolean isBorrowed=(resultSet.getInt("isBorrowed")==1); if(!isBorrowed){ System.out.println("書沒有被借出,不需要?dú)w還 bookId="+bookId); return false; } }else{ System.out.println("沒有該書! bookId="+bookId); return false; } sql="update book set isBorrowed=0 where id=?"; statement2=connection.prepareStatement(sql); statement2.setInt(1,bookId); int ret = statement2.executeUpdate(); if(ret!=1) return false; return true; } catch (SQLException e) { e.printStackTrace(); }finally { if(resultSet!=null) { try { connection.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(statement!=null) { try { statement.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(statement2!=null) { try { statement2.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } if(connection!=null){ try { connection.close(); } catch (SQLException throwables) { throwables.printStackTrace(); } } } return false; } }
針對用戶表的操作
public class UserDao { //根據(jù)用戶名找密碼的邏輯 //username是unique約束的 public user selectByName(String name){ Connection connection=null; PreparedStatement statement=null; ResultSet resultSet=null; try { connection=DBUtil.getConnection(); String sql="select* from user where username=?"; statement=connection.prepareStatement(sql); statement.setString(1,name); resultSet = statement.executeQuery(); if(resultSet.next()){ boolean isAdmin=(resultSet.getInt("isAdmin")==1); user users=null; if(isAdmin){ users=new Admin(); }else users=new NormalUser(); users.setPassWord(resultSet.getString("password")); users.setUserId(resultSet.getInt("userId")); users.setUserName(resultSet.getString("username")); return users; } } catch (SQLException e) { e.printStackTrace(); }finally { DBUtil.close(resultSet,statement,connection); } return null; } }
編寫主邏輯(main方法和login方法)
public class Main { public static void main(String[] args) { user users=login(); while(true){ int choice=users.menu(); users.doOperation(choice); } } private static user login(){ Scanner sc=new Scanner(System.in); System.out.println("請輸入用戶名"); String name=sc.next(); System.out.println("請輸入密碼"); String password=sc.next(); UserDao userDao=new UserDao(); user users=userDao.selectByName(name); if(users==null){ System.out.println("登陸失??!"); System.exit(0); } if(!users.getPassWord().equals(password)){ System.out.println("密碼錯誤"); System.exit(0); } return users; } }
編寫operation各種細(xì)節(jié)
將所有operations操作放在一個包中,定義一個接口operations,所有操作實(shí)現(xiàn)這個接口并重寫方法
IOperation接口
public interface IOperation { void work(); }
添加書籍操作
public class AddOperation implements IOperation{ @Override public void work() { System.out.println("新增書籍!"); Scanner sc=new Scanner(System.in); System.out.println("請輸入書名"); String name=sc.next(); System.out.println("請輸入作者"); String author=sc.next(); System.out.println("請輸入價格"); int price=sc.nextInt(); System.out.println("請輸入類別"); String type=sc.next(); Books book=new Books(); book.setName(name); book.setPrice(price); book.setType(type); book.setAuthor(author); BookDAO bookDAO=new BookDAO(); boolean ret=bookDAO.add(book); if(ret) System.out.println("新增成功"); else System.out.println("新增失敗"); } }
借書操作
public class BorrowOperation implements IOperation { @Override public void work() { System.out.println("借閱書籍"); System.out.println("請輸入要借閱的書籍id"); Scanner sc=new Scanner(System.in); int id=sc.nextInt(); BookDAO bookDAO=new BookDAO(); boolean ret = bookDAO.borrowBook(id); } }
刪除書籍操作
public class DelOperation implements IOperation{ @Override public void work() { System.out.println("刪除書籍!"); Scanner sc=new Scanner(System.in); System.out.println("請輸入刪除書籍的id"); int id=sc.nextInt(); BookDAO bookDAO=new BookDAO(); boolean ret = bookDAO.delete(id); if(ret) System.out.println("刪除成功"); else System.out.println("刪除失敗"); } }
查看書籍列表操作
public class DisplayOperation implements IOperation { @Override public void work() { System.out.println("展示所有書籍"); BookDAO bookdao=new BookDAO(); List<Books> list=bookdao.selectAll(); for(Books book:list){ System.out.println(book); } System.out.println("展示書籍完畢"); } }
退出系統(tǒng)操作
public class ExitOperation implements IOperation{ @Override public void work() { System.out.println("退出程序"); System.exit(0); } }
查找書籍操作
public class FindOperation implements IOperation{ @Override public void work() { System.out.println("根據(jù)名字查找書籍"); System.out.println("請輸入書名"); Scanner sc=new Scanner(System.in); String name=sc.next(); BookDAO bookDAO=new BookDAO(); List<Books> books = bookDAO.selectByName(name); for(Books book:books){ System.out.println(book); } System.out.println("根據(jù)名字查找書籍完畢"); } }
還書操作
public class ReturnOperation implements IOperation{ @Override public void work() { System.out.println("歸還書籍!"); System.out.println("請輸入要?dú)w還的書籍的id"); Scanner sc=new Scanner(System.in); int id=sc.nextInt(); BookDAO bookDAO=new BookDAO(); boolean ret = bookDAO.returnBook(id); if(ret){ System.out.println("歸還成功"); }else{ System.out.println("歸還失敗"); } } }
總結(jié):簡單的圖書管理系統(tǒng),通過練習(xí)掌握簡單JDBC語法和API,同時可以幫助理解java中多態(tài)繼承等概念。
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