JSP + eclipse做的一个入门代码

package Common; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import Entity.Title; public class Conn { Connection conn=null; PreparedStatement ps=null; ResultSet rs=null; //连接数据库 public Connection getConn() { try { Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); String url="jdbc:sqlserver://localhost:1433;databasename=books"; conn=DriverManager.getConnection(url,"sa","123456"); }catch(Exception e) { e.printStackTrace(); } return conn; } //查询所有的书 public ArrayList findbookall() { ArrayList al=new ArrayList(); try{ conn=this.getConn(); String sql="select * from titles"; ps=conn.prepareStatement(sql); rs=ps.executeQuery(); while(rs.next()) { Title title=new Title(); title.setIsbn(rs.getString("isbn")); title.setTitle(rs.getString("title")); title.setCopyright(rs.getString("copyright")); title.setImageFile(rs.getString("imageFile")); title.setEditionNumber(rs.getInt("editionNumber")); title.setPublisherID(rs.getInt("publisherID")); title.setPrice(rs.getDouble("price")); al.add(title); } }catch(Exception e) { e.printStackTrace(); } finally { this.closeconn(conn); this.closers(rs); this.closeps(ps); } return al; } //通过isbn查询书 public Title findbookbyisbn(String isbn) { Title title=new Title(); try{ conn=this.getConn(); String sql="select * from titles where isbn=?"; ps=conn.prepareStatement(sql); ps.setString(1, isbn); rs=ps.executeQuery(); while(rs.next()) { title.setIsbn(rs.getString("isbn")); System.out.print(rs.getString("isbn")); title.setTitle(rs.getString("title")); title.setCopyright(rs.getString("copyright")); title.setImageFile(rs.getString("imageFile")); title.setEditionNumber(rs.getInt("editionNumber")); title.setPublisherID(rs.getInt("publisherID")); title.setPrice(rs.getDouble("price")); } }catch(Exception e) { e.printStackTrace(); } finally { this.closeconn(conn); this.closers(rs); this.closeps(ps); } return title; } //关闭连接 public void closeconn(Connection conn) { if(conn!=null) { try { conn.close(); }catch(Exception e) { e.printStackTrace(); } } } //关闭数据集 public void closers(ResultSet rs) { if(rs!=null) { try { rs.close(); }catch(Exception e) { e.printStackTrace(); } } } //关闭preparedstatement public void closeps(PreparedStatement ps) { if(ps!=null) { try { ps.close(); }catch(Exception e) { e.printStackTrace(); } } } }