图书管理系统入门项目

登录功能实现

数据库：

创建用户表：

对应的实体类：

public class User {private int id;private String userName;private String password;}
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添加set，get方法，构造器new时按照要求添加
方法

    public User login(Connection conn,User user ) throws Exception {User resUser = null;String sql = "select * from user where userName=? and password=?";PreparedStatement pt = conn.prepareStatement(sql);pt.setString(1, user.getUserName());pt.setString(2, user.getPassword());ResultSet res = pt.executeQuery();if(res.next()) {resUser = new User();resUser.setId(res.getInt("id"));resUser.setUserName(res.getString("userName"));resUser.setPassword(res.getString("password"));}return resUser;}
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数据库连接

/*** 数据库连接   * @return* @throws Exception*/public Connection getConn () throws Exception {Class.forName("com.mysql.jdbc.Driver");Connection conn=DriverManager.getConnection(dbUrl, dbUserName, dbPassword);return conn;}//关闭数据库public void closeConn(Connection conn)throws Exception{if(conn!=null)conn.close();}
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创建图书表

实体类。。（各种省略）
添加图书：

public int add(Connection conn, Book book) throws Exception {String sql = "insert into book values (null,?,?,?,?,?)";PreparedStatement pmt = conn.prepareStatement(sql);pmt.setObject(1, book.getBookName());pmt.setObject(2, book.getAutor());pmt.setObject(3, book.getTotalStock());pmt.setObject(4, book.getPresentStock());pmt.setObject(5, book.getBookTypeUId());return pmt.executeUpdate();//返回改变记录数}
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查询：

public ResultSet list(Connection conn,Book book) throws Exception {StringBuffer sb = new StringBuffer("select * from book,book_type where book.bookTypeId = book_type.id ");if(StringUtil.isNotEmpty(book.getBookName())) {       sb.append("and book.bookName like '%"+book.getBookName()+"%'");}if(StringUtil.isNotEmpty(book.getAutor())) {sb.append("and book.autor like '%"+book.getAutor()+"%'");}if(book.getBookTypeUId()!=null&& book.getBookTypeUId()!=-1) {sb.append("and book.bookTypeId = "+book.getBookTypeUId());}PreparedStatement pmt=conn.prepareStatement(sb.toString());return pmt.executeQuery();//返回结果集
}
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删除图书：

public int delete(Connection conn ,String id)throws Exception{String sql = "delete from book where id = ?";PreparedStatement pmt = conn.prepareStatement(sql);pmt.setObject(1, id);return pmt.executeUpdate();//返回删除数
}
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修改图书信息：

public int update(Connection conn , Book book)throws Exception{String sql = "update book set bookName = ?,autor = ?,bookTypeId = ? where id = ?";PreparedStatement pmt = conn.prepareStatement(sql);pmt.setObject(1, book.getBookName());pmt.setObject(2, book.getAutor());pmt.setObject(3, book.getBookTypeUId());pmt.setObject(4, book.getId());return pmt.executeUpdate(); //返回修改数
}
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图书管理简单的几个功能实现。！！

每天进步一点！！