jdbc+servlet+jsp员工信息管理(emp表)

package com.hyxy.dao.impl; import java.sql.Connection; import java.sql.Date; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import com.hyxy.dao.EmpDao; import com.hyxy.entity.Emp; import com.hyxy.util.DBUtil; /** * 编写接口EmpDao的实现类，实现持久层的 * 业务逻辑 */ public class EmpDaoImpl implements EmpDao{ @Override public void saveEmp(Emp emp) { Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "insert into emp (ename,job,mgr,hiredate,sal,comm,deptno)values(?,?,?,?,?,?,?)"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, emp.getEname()); ps.setString(2, emp.getJob()); ps.setInt(3, emp.getMgr()); ps.setDate(4, emp.getHiredate()); ps.setDouble(5, emp.getSal()); ps.setDouble(6, emp.getComm()); ps.setInt(7, emp.getDeptno()); ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } } @Override public void delEmp(Integer empno) { Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "delete from emp where empno=?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, empno); ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } } @Override public void updateEmp(Emp emp) { Connection conn = null; try { //获取连接对象 conn = DBUtil.getConnection(); String sql = "update emp set ename=?,job=?,mgr=?,hiredate=?,sal=?,comm=?,deptno=? where empno=?"; //获取预编译对象 PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, emp.getEname()); ps.setString(2, emp.getJob()); ps.setInt(3, emp.getMgr()); ps.setDate(4, emp.getHiredate()); ps.setDouble(5, emp.getSal()); ps.setDouble(6, emp.getComm()); ps.setInt(7, emp.getDeptno()); ps.setInt(8, emp.getEmpno()); ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } } @Override public Emp findById(Integer empno) { Emp emp = null; Connection conn = null; try { //获取连接对象 conn = DBUtil.getConnection(); String sql = "select * from emp where empno=?"; //获取预编译对象 PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, empno); //执行sql语句，处理结果集 ResultSet rs = ps.executeQuery(); if(rs.next()) { String ename = rs.getString("ename"); String job = rs.getString("job"); int mgr = rs.getInt("mgr"); Date hiredate = rs.getDate("hiredate"); double sal = rs.getDouble("sal"); double comm = rs.getDouble("comm"); int deptno = rs.getInt("deptno"); //将这些数据封装成一个Emp对象 emp = new Emp(empno, ename, job, mgr, hiredate, sal, comm, deptno); } } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } return emp; } @Override public List<Emp> findAll() { Connection conn = null; List<Emp> emps = new ArrayList<Emp>(); try { conn = DBUtil.getConnection(); String sql = "select * from emp"; PreparedStatement ps = conn.prepareStatement(sql); /* * 4：处理结果集 * executeQuery():将查询的N条记录 * 封装到ResultSet类型中 * 此类型与迭代器相似，我们应该 * 先询问是有下一条记录(boolean next()) * 如果有，光标自动移至下一行，我们就 * 可以对此行进行处理 */ ResultSet rs = ps.executeQuery(); while(rs.next()) {//询问 //进入循环体，说明有下一行，并且光标已经移至下一行了。 /* * jdbc的结果集类型中为表中字段提供了 * 两个重载方法 * 如: int getInt(int columnIndex) * int getInt(String columnName); * 每种类型都有两个方法，如上。 */ int empno = rs.getInt(1);// String ename = rs.getString(2); String job = rs.getString(3); int mgr = rs.getInt(4); Date hiredate = rs.getDate("hiredate"); double sal = rs.getDouble("sal"); double comm = rs.getDouble("comm"); int deptno = rs.getInt("deptno"); //封装成对象 Emp emp = new Emp(empno, ename, job, mgr, hiredate, sal, comm, deptno); //添加到集合中 emps.add(emp); } } catch (Exception e) { e.printStackTrace(); }finally { DBUtil.closeConnection(conn); } return emps; } @Override public List<Emp> findByPage(int page, int size) { Connection conn = null; List<Emp> emps = new ArrayList<Emp>(); try { //获取连接对象 conn = DBUtil.getConnection(); String sql = "select * from emp order by empno limit ?,?"; //String sql1 = "select * from emp where empno>((?-1)*?) order by empno limit ?"; //获取预编译对象 PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, (page-1)*size); ps.setInt(2, size); //执行sql语句，处理结果集 ResultSet rs = ps.executeQuery(); Emp emp = null; while(rs.next()) { int empno = rs.getInt("empno"); String ename = rs.getString("ename"); String job = rs.getString("job"); int mgr = rs.getInt("mgr"); Date hiredate = rs.getDate("hiredate"); double sal = rs.getDouble("sal"); double comm = rs.getDouble("comm"); int deptno = rs.getInt("deptno"); //封装成Emp对象 emp = new Emp(empno, ename, job, mgr, hiredate, sal, comm, deptno); //添加到集合中 emps.add(emp); } } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } return emps; } @Override public int totalPage(int size) { Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "select count(*) from emp"; PreparedStatement ps = conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); int lines = -1; if(rs.next()) { lines = rs.getInt(1); } //计算总页数 int totalPage = lines%size==0?lines/size:lines/size+1; return totalPage; } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeConnection(conn); } return 0; } }