jdbc数据库中的增删改
Posted *眉间缘*
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HttpSession session=request.getSession(); session.setAttribute("currentUser",u.username);//获取用户名
servlet中不能直接获取session
package com.hanqi.dal; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.Date; import java.util.List; import com.hanqi.model.AppUser; import com.hanqi.model.Dept; import com.hanqi.model.Emp; import com.hanqi.util.JdbcConnectionUtil; public class MethodDal { private Connection con; private PreparedStatement ps; private ResultSet rs; // 添加一条数据 public int insertData() { init(); int i = -1; String sql = "insert into course" + "values(‘11‘,‘cc‘,‘33‘)"; try { ps = con.prepareStatement(sql); i = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } close(); return i; } // 添加制定的参数 public int insertData(AppUser user) { init(); int i = -1; String sql = "insert into course" + "values(?,?,?)"; //long l = new Date().getTime(); try { ps = con.prepareStatement(sql); ps.setString(1, user.getUsername()); ps.setString(2, user.getPassword()); ps.setString(3, user.getRealname()); //ps.setDate(4, new java.sql.Date(l)); i = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } close(); return i; } // 批量添加数据 public int[] insertBatchData() { init(); int[] arr = null; try { String sql = "insert into appuser values(?,?,?)"; ps = con.prepareStatement(sql); for (int i = 0; i < 5; i++) { ps.setString(1, "11" + i); ps.setString(2, "cc" + i); ps.setString(3, "22" + i); ps.addBatch(); } arr = ps.executeBatch(); } catch (SQLException e) { e.printStackTrace(); } close(); return arr; } // 删除一条记录 public int deleteData(int cno) { init(); int i = -1; String sql = "delete course c where c.cno=?"; try { ps = con.prepareStatement(sql); ps.setInt(1, cno); i = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } close(); return i; } // 更新表中的数据 public int updateData(int id, String realname) { init(); int i = -1; String sql = "update course c set c.cname=? where c.cno=?"; try { ps = con.prepareStatement(sql); ps.setString(1, cname); ps.setInt(2, cno); i = ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); } close(); return i; } public List<AppUser> selectAppUser() { String sql = "select a.id,a.username hh,a.password,a.realname,a.createtime from appuser a where a.id in (76,73)"; init(); List<AppUser> list = new ArrayList<AppUser>(); try { ps = con.prepareStatement(sql); rs = ps.executeQuery(); while (rs.next()) { AppUser au = new AppUser(); au.setId(rs.getInt(1)); au.setUsername(rs.getString(2)); au.setPassword(rs.getString(3)); au.setRealname(rs.getString(4)); au.setCreatetime(rs.getDate(5)); list.add(au); } } catch (SQLException e) { e.printStackTrace(); } close(); return list; } public void init() { con = JdbcConnectionUtil.getConnection(); } public void close() { JdbcConnectionUtil.destroy(con, ps, rs); } }
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