JAVA操作数据库的增删改查

package com.oracle.dao;


import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import java.util.LinkedList;

import com.oracle.model.Emp;

public class EmpDao {
     public int add(Connection conn,Emp emp) throws Exception{
         String sql="insert into emp values(?,?,?,?,?,?,?,?)";
         PreparedStatement pst=conn.prepareStatement(sql);
         pst.setInt(1, emp.getEmpno());
         pst.setString(2, emp.getEname());
         pst.setString(3, emp.getJob());
         pst.setInt(4, emp.getMgr());
         pst.setString(5, emp.getHiredate());
         pst.setDouble(6, emp.getSal());
         pst.setDouble(7,emp.getComm());
         pst.setInt(8, emp.getDeptno());
         return pst.executeUpdate();
     }
     public int modify(Connection conn,Emp emp) throws Exception{
         String sql ="Update emp set empno=?,ename=?,job=?,mgr=?,hiredate=?,sal=?,comm=?,deptno=?";
         PreparedStatement pst = conn.prepareStatement(sql);
         pst.setInt(1, emp.getEmpno());
         pst.setString(2, emp.getEname());
         pst.setString(3, emp.getJob());
         pst.setInt(4, emp.getMgr());
         pst.setString(5, emp.getHiredate());
         pst.setDouble(6, emp.getSal());
         pst.setDouble(7,emp.getComm());
         pst.setInt(8, emp.getDeptno());
         return pst.executeUpdate();
     }
     public int del(Connection conn,Emp emp) throws Exception{
         String sql="delete from emp where empno=?";
         PreparedStatement pst = conn.prepareStatement(sql);
         pst.setInt(1, emp.getDeptno());
         return pst.executeUpdate();
     }
     public LinkedList<Emp> findAll(Connection conn) throws Exception{
         String sql="select empno,ename,job,mgr,hiredate,sal,comm,deptno from emp";
         PreparedStatement pst =conn.prepareStatement(sql);
         ResultSet rs=pst.executeQuery();
         LinkedList<Emp> arr=new LinkedList<Emp>();
         while(rs.next()) {
             Emp emp = new Emp();
             emp.setEmpno(rs.getInt("empno"));
             emp.setEname(rs.getString("ename"));
             emp.setJob(rs.getString("job"));
             emp.setMgr(rs.getInt("mgr"));
             emp.setHiredate(rs.getString("hiredate"));
             emp.setSal(rs.getDouble("sal"));
             emp.setComm(rs.getDouble("comm"));
             emp.setDeptno(rs.getInt("deptno"));
             arr.add(emp);
             
             
         }
        return arr;         
     }
}