jsp＋servlet 增删改查

package dao; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import javabean.person; public class udao { Connection con=null; PreparedStatement ps=null; ResultSet rs=null; public udao()//获得链接方法 { try { Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver"); String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=data"; try { con=DriverManager.getConnection(url, "sa", "sa"); } catch (SQLException e) { e.printStackTrace(); } } catch (ClassNotFoundException e) { e.printStackTrace(); } } public void closeConnection()//关闭链接释放资源的方法 { if(rs!=null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if(ps!=null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } } if(con!=null) { try { con.close(); } catch (SQLException e) { e.printStackTrace(); } } } public ArrayList<person> getall() { ArrayList<person> a = new ArrayList<person>(); String sql = "select * from person"; try { ps = con.prepareStatement(sql); rs = ps.executeQuery(); while (rs.next()) { person p = new person(); p.setId(rs.getInt("ID")); p.setName(rs.getString("name")); p.setAge(rs.getInt("age")); p.setSex(rs.getString("sex")); a.add(p); } } catch (SQLException e) { e.printStackTrace(); } return a; } public int add(person p) { int n=0; String sql="insert into person values('"+p.getName()+"','"+p.getSex()+"',"+p.getAge()+")"; try { ps=con.prepareStatement(sql); n=ps.executeUpdate(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return n; } public int del(int id) { int n=0; String sql="delete from person where ID="+id+""; try { ps=con.prepareStatement(sql); n=ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return n; } public int update(person p,int id) { int m=0; String sql="update person set name='"+p.getName()+"', sex='"+p.getSex()+"',age="+p.getAge()+" where id="+id+""; try { ps=con.prepareStatement(sql); m=ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } return m; } public ArrayList<person> getone(int id) { ArrayList<person> a=new ArrayList<person>(); String sql="select * from person where id="+id+""; try { ps=con.prepareStatement(sql); rs=ps.executeQuery(); while(rs.next()) { person p=new person(); p.setName(rs.getString("name")); p.setAge(rs.getInt("age")); p.setSex(rs.getString("sex")); p.setId(rs.getInt("id")); a.add(p); } } catch (SQLException e) { e.printStackTrace(); } return a; } }