圖書管理系統(JDBC)

public class BookSystem{   //圖書系統管理類

 private Scanner sc =new Scanner(System.in);

public static void main(String[] args){

           BookSystem bs = new BookSystem();

           bs.start();

}

public void start(){

while (true){

System.out.println("請輸入要執行的命令");
 System.out.println("-----------------------------------------------------");
 System.out.println("---------------------圖書管理系統---------------------");
 System.out.println(" 1.增加圖書 2.查找圖書");
 System.out.println(" 3.修改圖書 4.刪除圖書");
 System.out.println(" 5.列出所有圖書 6.退出系統");
 System.out.println("----------------------------------------------------");

int command = sc.nextInt();

if (command==1){
 insertNewBook();

}else if (command==2){
 updateBook();

}else if (command==3){
 deleteBook();

}else if (command==4){
 selectBook();

}else if (command==5){
 listAll();
}else {
 System.out.println("退出系統");
}

public void insertNewBook(){
        System.out.println("請輸入書的名字");
 String bookName = sc.next();
 System.out.println("請輸入書的作者");
 String author = sc.next();
 System.out.println("請輸入書的ISBN");
 String isbn = sc.next();

 Book book = new Book();
 book.setName(bookName);
 book.setAuthor(author);
 book.setIsbn(isbn);

 //把book對象交給數據庫來處理
 int result = BookDB.insertBook(book);
 if (result>0){
 System.out.println("添加成功");
 }else {
 System.out.println("添加失敗");
 }
 }

 public void updateBook(){
 System.out.println("請輸入修改的書名");
 String bookname = sc.next();
 Book book =new Book();
 book.setName(bookname);
 int result = BookDB.updateBook(book);
 if(result>0){
 System.out.println("修改成功");
 }else{
 System.out.println("修改失敗");
 }
 }
 public void deleteBook(){
 System.out.println("請輸入要刪除的書名");
 String newbook = sc.next();
 Book book =new Book();
 book.setName(newbook);
 int result = BookDB.deleteBook(book);
 if (result>0){
 System.out.println("刪除成功");
 }else {
 System.out.println("刪除失敗");
 }
 }

 public void selectBook(){
 Book book = BookDB.selectBook();
 System.out.println(book);

 }
 public void listAll(){
 List<Book> list = BookDB.listAll();
 if (list.size() == 0){
 System.out.println("暫無書籍信息");
 System.out.println("是否要添加新的書籍:Y/N");
 String input = sc.next();
 if ("y".equals(input.toLowerCase())){
 insertNewBook();
 }
 }
 for (Book book : list) {
 System.out.println(book.getBid()+":"+book.getName());
 }
 }

}
public class BookDB { //專門處理圖書管理,數據部分

    public static int insertBook(Book book) {
 String sql = "insert into book(name,author,isbn) values (?,?,?)";
 return DBUtils.update(sql,book.getName(),book.getAuthor(),book.getIsbn());
 }

 public static List<Book> listAll(){
 Connection conn = DBUtils.getConn();
 String sql ="select * from book";
 PreparedStatement stmt=null;
 ResultSet rs=null;

 List<Book> list = new ArrayList<>();
 try {
 stmt = conn.prepareStatement(sql);
 rs = stmt.executeQuery();
 while (rs.next()){
 Book book = new Book();
 book.setName(rs.getString("name"));
 book.setAuthor(rs.getString("author"));
 book.setIsbn(rs.getString("isbn"));
 book.setBid(rs.getInt("id"));
 list.add(book);
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }finally {
 DBUtils.closeAll(conn,stmt,rs);
 }
 return list;
 }

 public static int updateBook(Book book){
 String sql ="update book set name=? where name=? ";
 System.out.println("請輸入修改的書名");
 Scanner sc = new Scanner(System.in);
 return DBUtils.update(sql,book.getName(),sc.next());
 }

 public static Book selectBook(){
 Connection conn=null;
 PreparedStatement stmt=null;
 ResultSet rs=null;
 conn = DBUtils.getConn();
 String sql ="select * from book where name=?";
 try {
 stmt = conn.prepareStatement(sql);
 Scanner sc =new Scanner(System.in);
 System.out.println("請輸入查找的書名");
 stmt.setString(1,sc.next());
 rs = stmt.executeQuery();
 while (rs.next()){
 Book book1 = new Book();
 book1.setName(rs.getString("name"));
 book1.setAuthor(rs.getString("author"));
 book1.setIsbn(rs.getString("isbn"));
 book1.setBid(rs.getInt("id"));
 return book1;
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }finally {
 DBUtils.closeAll(conn,stmt,rs);
 }
 return null;
 }

 public static int deleteBook(Book book){
 String sql ="delete from book where name =?";
 System.out.println("請輸入刪除的書名");
 Scanner sc = new Scanner(System.in);
 return DBUtils.update(sql,sc.next());
 }

}

public class DBUtils {// 工具類
public static void closeAll(Connection conn, PreparedStatement stmt, ResultSet rs) {
        try {
 if (conn != null) {
 conn.close();
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 try {
 if (stmt != null) {
 stmt.close();
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 try {
 if (rs != null) {
 rs.close();
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 }
 // 創建一個數據庫連接(封裝方法)
 public static Connection getConn() {
 // url規定數據庫連接的類型,地址,端口,和數據庫名,后面可以接參數
 String url = "jdbc:mysql://localhost:3306/j0302?useSSL=true";
 String username = "root";
 String password = "123456";
 String driver = "com.mysql.jdbc.Driver";
 try {
 Class.forName(driver);
 Connection conn =
 DriverManager.getConnection(url, username, password);
 return conn;
 } catch (ClassNotFoundException e) {
 e.printStackTrace();
 throw new RuntimeException("驅動未找到");
 } catch (SQLException e) {
 e.printStackTrace();
 throw new RuntimeException("數據庫連接失敗");
 }
 }
 // 不定長參數
 public static int update(String sql, Object... obArray){
 Connection conn = DBUtils.getConn();
 PreparedStatement stmt=null;
 try {
 stmt = conn.prepareStatement(sql);
 for (int i = 0; i < obArray.length; i++) {
 stmt.setObject(i+1,obArray[i]);
 }
 int result = stmt.executeUpdate();
 return result;
 } catch (SQLException e) {
 e.printStackTrace();
 }finally {
 DBUtils.closeAll(conn,stmt,null);
 }
 // 如果代碼執行到這個位置,那么肯定是出了異常
 // 這個時候直接返回0;
 return 0;
 }
 }