完善Java图书管理系统
原本功能:
1. 用户登录
2. 增加图书
3. 修改图书信息
4. 删除图书信息
5.查询图书
6. 查看所有的图书
扩充功能：
1. 借阅图书（输入书名和借阅人姓名，库存量为0的图书不能再借）
2. 还书功能（根据书名进行还书）
源码：
BookManager是和用户进行交互，在控制台显示信息提示用户如何操作，并且调用dao查询数据库拿到结果返回给用户。
1 public class BookManager{ 2 LinkedHashMap<String, Book> stu = new LinkedHashMap<String, Book>(); 3 Book book = new Book(); 4 Scanner sc = new Scanner(System.in); 5 6 public void Manage(int choice) throws Exception{ 7 switch (choice) { 8 case 0: 9 list(); 10 break; 11 case 1: 12 find(); 13 break; 14 case 2: 15 add(); 16 break; 17 case 3: 18 modify(); 19 break; 20 case 4: 21 delete(); 22 break; 23 default: { 24 throw new Exception("没有该功能，请重新选择！"); 25 } 26 } 27 } 28 29 //获取所有书籍 30 public void list() { 31 Dao dao = new Dao(); 32 List<Book> list = dao.getAllBooks(); 33 System.out.println("书籍列表如下："); 34 for(Book book : list) { 35 System.out.println("书名："+book.getName()+" 作者："+book.getAuthor()+" 库存量："+book.getNum()); 36 } 37 } 38 39 //搜索书籍 40 public void find() { 41 System.out.println("输入要搜索的书名："); 42 String name = sc.next(); 43 Dao dao = new Dao(); 44 if(!dao.judgeExist(name)) 45 System.out.println("该书籍不存在！"); 46 else{ 47 Book book = dao.find(name); 48 System.out.println("书名："+book.getName()+" 作者："+book.getAuthor()+" 库存量："+book.getNum()); 49 } 50 } 51 52 //添加书籍 53 public void add() { 54 Dao dao = new Dao(); 55 System.out.println("输入要添加的书名："); 56 String name = sc.next(); 57 if(dao.judgeExist(name)) 58 System.out.println("该书籍已存在！"); 59 else{ 60 System.out.println("输入作者："); 61 String author = sc.next(); 62 System.out.println("输入数量："); 63 int num = sc.nextInt(); 64 dao.addBook(new Book(name,author,num)); 65 System.out.println("添加成功！"); 66 list(); 67 } 68 } 69 70 //修改书籍 71 public void modify(){ 72 System.out.println("输入要修改的书名："); 73 String name = sc.next(); 74 Dao dao = new Dao(); 75 if(!dao.judgeExist(name)) 76 System.out.println("该书籍不存在！"); 77 else{ 78 Book book = dao.find(name); 79 System.out.println("书名："+book.getName()+" 作者："+book.getAuthor()+" 库存量："+book.getNum()); 80 System.out.println("输入修改后的书名："); 81 String newname = sc.next(); 82 System.out.println("输入修改后的作者："); 83 String newauthor = sc.next(); 84 System.out.println("输入修改后的库存量："); 85 int newnum = sc.nextInt(); 86 dao.modifyBook(name, new Book(newname,newauthor,newnum)); 87 System.out.println("修改成功！"); 88 } 89 } 90 91 //删除书籍 92 public void delete() { 93 System.out.println("请输入要删除的书名："); 94 String name = sc.next(); 95 Dao dao = new Dao(); 96 if(!dao.judgeExist(name)) { 97 System.out.println("书籍不存在！"); 98 } 99 else{ 100 dao.deleteBook(name); 101 System.out.println("删除成功！"); 102 } 103 } 104 }
Dao类就是和数据库交互，执行sql语句从数据库取得结果。
1 public class Dao { 2 3 /** 4 * 根据书名判定书籍是否已存在 5 */ 6 public boolean judgeExist(String targetName){ 7 Connection conn = null; 8 PreparedStatement stmt = null; 9 ResultSet rs = null; 10 int count = 0; 11 try { 12 conn = MySQLUtils.getConn(); 13 String sql = "select count(*) as count from book where book_name = ?"; 14 stmt = conn.prepareStatement(sql); 15 stmt.setString(1, targetName); 16 rs = stmt.executeQuery(); 17 while(rs.next()){ 18 count = rs.getInt("count"); 19 } 20 } 21 catch (SQLException e) { 22 e.printStackTrace(); 23 } 24 finally{ 25 MySQLUtils.closeConn(conn, stmt, rs); 26 } 27 if(count==0) return false; 28 else 29 return true; 30 } 31 32 33 /** 34 * 获取所有书籍列表 35 */ 36 public List<Book> getAllBooks(){ 37 Connection conn = null; 38 Statement stmt = null; 39 ResultSet rs = null; 40 List<Book> bookList = new ArrayList<>(); 41 try { 42 43 conn = MySQLUtils.getConn(); 44 String sql = "select * from book"; 45 stmt = conn.createStatement(); 46 rs = stmt.executeQuery(sql); 47 while(rs.next()){ 48 String name = rs.getString("book_name"); 49 String author = rs.getString("book_author"); 50 int num = rs.getInt("book_num"); 51 Book book = new Book(name, author, num); 52 bookList.add(book); 53 } 54 } 55 catch (SQLException e) { 56 e.printStackTrace(); 57 } 58 finally{ 59 MySQLUtils.closeConn(conn, stmt, rs); 60 } 61 return bookList; 62 } 63 64 /** 65 * 根据书名查找书籍详细信息 66 */ 67 public Book find(String bookName){ 68 Connection conn = null; 69 PreparedStatement stmt = null; 70 Book book = null; 71 try { 72 conn = MySQLUtils.getConn(); 73 String sql = "select * from book where book_name = ?"; 74 stmt = conn.prepareStatement(sql); 75 stmt.setString(1, bookName); 76 ResultSet tmpres = stmt.executeQuery(); 77 book = new Book(); 78 while(tmpres.next()){ 79 book.setName(tmpres.getString("book_name")); 80 book.setAuthor(tmpres.getString("book_author")); 81 book.setNum(tmpres.getInt("book_num")); 82 } 83 } 84 catch (SQLException e) { 85 e.printStackTrace(); 86 } 87 finally{ 88 MySQLUtils.closeConn(conn, stmt); 89 } 90 return book; 91 } 92 93 /** 94 * 添书 95 */ 96 public void addBook(Book book){ 97 Connection conn = null; 98 PreparedStatement stmt = null; 99 try { 100 conn = MySQLUtils.getConn(); 101 String sql = "insert into book(book_name, book_author, book_num) values(?,?,?)"; 102 stmt = conn.prepareStatement(sql); 103 stmt.setString(1, book.getName()); 104 stmt.setString(2, book.getAuthor()); 105 stmt.setInt(3, book.getNum()); 106 stmt.executeUpdate(); 107 } 108 catch (SQLException e) { 109 e.printStackTrace(); 110 } 111 finally{ 112 MySQLUtils.closeConn(conn, stmt); 113 } 114 } 115 116 /** 117 * 修改书 118 */ 119 public void modifyBook(String targetName, Book book){ 120 Connection conn = null; 121 PreparedStatement stmt = null; 122 try { 123 conn = MySQLUtils.getConn(); 124 String sql = "update book set book_name = ?, book_author = ?, book_num = ? where book_name = ?"; 125 stmt = conn.prepareStatement(sql); 126 stmt.setString(1, book.getName()); 127 stmt.setString(2, book.getAuthor()); 128 stmt.setInt(3, book.getNum()); 129 stmt.setString(4, targetName); 130 stmt.executeUpdate(); 131 } 132 catch (SQLException e) { 133 e.printStackTrace(); 134 } 135 finally{ 136 MySQLUtils.closeConn(conn, stmt); 137 } 138 } 139 140 /** 141 * 删书 142 */ 143 public void deleteBook(String bookName){ 144 Connection conn = null; 145 PreparedStatement stmt = null; 146 try { 147 conn = MySQLUtils.getConn(); 148 String sql = "delete from book where book_name = ?"; 149 stmt = conn.prepareStatement(sql); 150 stmt.setString(1, bookName); 151 stmt.executeUpdate(); 152 } 153 catch (SQLException e) { 154 e.printStackTrace(); 155 } 156 finally{ 157 MySQLUtils.closeConn(conn, stmt); 158 } 159 } 160 }
扩充：
借阅功能（在Dao中增加下列函数）
1 // 检查书是否存在馆里和是否已借出 2 public int testReader(String bookname) { 3 4 // 馆里有此书，查找此书的索引，有此书a>=0，无返-1 5 int a = selectIndex(bookname); 6 // 馆里有此书 7 if (a >= 0) { 8 if ((book.borrowreaders[a].equals("无") || book.borrowreaders[a].equals("")))// 无人借此书，""为扫描器的直接回车值 9 return 0;//未借 10 else 11 return 1;//已借 12 } else { 13 return -1;// 馆里没有此书 14 } 15 16 } 17 //将借阅者设置为无或者为空 18 public void setBorrowReader(String bookname){ 19 int a = selectIndex(bookname); 20 book.borrowreaders[a]="无"; 21 } 22 //查询指定书的借阅者 23 public String getBorrowReader(String bookname){ 24 int a = selectIndex(bookname); 25 return book.borrowreaders[a]; 26 } 27 28 //书籍借阅功能 29 public void borrow(String bookname,String readername){ 30 int a = selectBook(bookname); 31 book.borrowreaders[a]=readername; 32 } 33 }
还书功能（在BookManager类中增加下列函数）
1 // 还书功能 2 public void returnBook() { 3 System.out.print("请输入要还的书籍名称："); 4 Scanner scanner = new Scanner(System.in); 5 String bookname = scanner.nextLine(); 6 int flag = bo.testReader(bookname); 7 if (flag == 0) { 8 System.out.println(bookname + "暂未借出。"); 9 System.out.print("输入0回车返回至主菜单，输入其他键则继续还书"); 10 String a = scanner.nextLine(); 11 if(a.equals("0")){ 12 showMenu(); 13 }else { 14 returnBook(); 15 } 16 } else if (flag == -1) { 17 System.out.println(bookname + "不存在该图书馆中。"); 18 System.out.print("输入0回车返回至主菜单，输入其他键则继续还书"); 19 String a = scanner.nextLine(); 20 if(a.equals("0")){ 21 showMenu(); 22 }else { 23 returnBook(); 24 } 25 } else if (flag == 1) { 26 27 System.out.println(bo.getBorrowReader(bookname) + "已经还书成功！"); 28 bo.setBorrowReader(bookname); 29 System.out.print("输入0回车返回至主菜单，输入其他键则继续还书"); 30 String a = scanner.nextLine(); 31 if(a.equals("0")){ 32 showMenu(); 33 }else { 34 returnBook(); 35 } 36 } 37 } 38 39 // 书籍借阅功能 40 public void borrowBook() { 41 System.out.print("请输入要借的书名："); 42 Scanner scanner = new Scanner(System.in); 43 String bookname = scanner.nextLine(); 44 int flag = bo.testReader(bookname); 45 switch (flag) { 46 case 0://存在此书并无人借的情况 47 48 System.out.println("请输入借阅者的名字："); 49 String readername = scanner.nextLine(); 50 bo.borrow(bookname,readername); 51 System.out.println(readername+"从该图书馆里借出了以"+bookname+"为名的书籍。"); 52 System.out.print("输入0回车返回至主菜单，输入1回车则继续借书："); 53 int a0 = scanner.nextInt(); 54 if(a0==0) 55 showMenu(); 56 if(a0==1) 57 borrowBook(); 58 break; 59 60 case 1://存在此书被借的情况 61 System.out.println("借书失败，" + bookname + "已被借！"); 62 System.out.print("输入0回车返回至主菜单，输入1回车则继续借书："); 63 int a = scanner.nextInt(); 64 switch (a) { 65 case 0: 66 showMenu(); 67 break; 68 69 case 1: 70 borrowBook(); 71 break; 72 73 } 74 case -1://不存在此书的情况 75 System.out.println("借书失败，" + bookname + "不存在该图书馆中。"); 76 System.out.print("输入0回车返回至主菜单，输入1回车则继续借书："); 77 int a1 = scanner.nextInt(); 78 switch (a1) { 79 case 0: 80 showMenu(); 81 break; 82 83 case 1: 84 borrowBook(); 85 break; 86 87 } 88 } 89 } 90 }
