基于javaee实现对学生信息的增删改查的2种方法

package Bean; import java.sql.*; import java.util.ArrayList; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletRequest; public class DBProcess { private HttpServletRequest request; private Connection con; private Statement stat; public DBProcess(HttpServletRequest request) { this.request=request; ServletContext ctx =request.getSession().getServletContext(); con=(Connection) ctx.getAttribute("DBCon"); } public void save() throws Exception { String insertSQL ="insert into student(stuid,stuName,sex,classname)value(?,?,?,?)"; String updateSQL="update student set stuid=?,stuName=?,sex=?,classname=?where id=?"; ArrayList<String> params=new ArrayList<String>(); params.add(request.getParameter("stuid")); params.add(request.getParameter("stuName")); params.add(request.getParameter("sex")); params.add(request.getParameter("classname")); String id =request.getParameter("id"); System.out.println(params.get(0)); if("".equals(id)) { exePrepare(insertSQL,params); System.out.println("..."); } else { params.add(id); exePrepare(updateSQL,params); } } public void getStudentList() throws SQLException { String sql="select *from student"; ResultSet rs=getRS(sql); ArrayList<Student>stuList=new ArrayList<Student>(); while(rs.next()) { stuList.add(toStudent(rs)); } System.out.println(stuList.size()); request.setAttribute("stuList", stuList); closeRS(rs); } private void closeRS(ResultSet rs) { try { stat.close(); rs.close(); }catch(SQLException e) { e.printStackTrace(); } } private ResultSet getRS(String sql) throws SQLException{ // TODO Auto-generated method stub stat=con.createStatement(); ResultSet res=stat.executeQuery(sql); return res; } public void getStuById() throws SQLException { String sql="select * from student where id="; String id=request.getParameter("id"); sql+=id; ResultSet rs=getRS(sql); while(rs.next()) { Student stu=toStudent(rs); request.setAttribute("stu",stu); } closeRS(rs); } public void deleteStuById() throws SQLException { String sql="delete from student where id=?"; String id=request.getParameter("id"); PreparedStatement pstat=con.prepareStatement(sql); pstat.setString(1,id); pstat.execute(); } private Student toStudent(ResultSet rs)throws SQLException { Student stu=new Student(); stu.setId(rs.getInt("id")); stu.setStuid(rs.getString("stuid")); stu.setStuName(rs.getString("stuName")); stu.setSex(rs.getString("sex")); stu.setClassname(rs.getString("classname")); System.out.println(stu.getClassname()); return stu; } private void exePrepare(String sql,ArrayList<String> params)throws SQLException { PreparedStatement pstat=con.prepareStatement(sql); int i=1; for(String param:params) { pstat.setString(i++,param); }pstat.execute(); pstat.close(); } }