java--学生信息管理3

Posted 2022-12-10 xanlv

在
http://blog.csdn.net/xanlv/article/details/53158999的基础上重写servlet
学习Hibernate的框架，重写servlet

在utils包中添加BaseServlet(不配置xml),当作一个基类使用

package cn.hncu.utils;

import java.io.IOException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public abstract class BaseServlet extends HttpServlet 

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 

        doPost(request, response);
    

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 

        String cmd=request.getParameter("cmd");//streth框架中称action
        if(cmd==null||cmd.toString().trim().equals(""))
            cmd="execute";//默认方法
        
        //调用子类中名为cmd的方法---利用类反射动态调
        try 
            Method m= this.getClass().getMethod(cmd, HttpServletRequest.class,HttpServletResponse.class);
            m.invoke(this, request,response);
         catch (Exception e) 
            throw new RuntimeException(e.getMessage(), e);
        

    
    public abstract void execute(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ;

继承BaseServlet,调用BaseServlet中的dopost，doget方法

package cn.hncu.stud.servlet;

import java.io.IOException;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.hncu.domain.Book;
import cn.hncu.domain.Stud;
import cn.hncu.stud.service.IStudService;
import cn.hncu.stud.service.StudServiceImpl;
import cn.hncu.utils.BaseServlet;
import cn.hncu.utils.TxProxy3;

public class QueryServlet extends BaseServlet

    IStudService service=TxProxy3.getProxy(new StudServiceImpl());
    public void query(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 
        System.out.println("service:"+service);
        List<Map<String, String>> studs=service.query();
        request.setAttribute("studs", studs);
        request.getRequestDispatcher("/jsps/show.jsp").forward(request, response);
    
    public void add(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 
        //1收集参数    2组织参数(id字段留到dao中去补)
        String name[]=request.getParameterValues("name");
        Stud s=new Stud();
        s.setName(name[0]);
        //图书信息
        String books[]=request.getParameterValues("book");
        //防护一下  ---价格的防护应该也要写，这里我们偷懒了
        if(books==null||books.length<=0)
            return;
        
        String prices[]=request.getParameterValues("price");
        for(int i=0;i<books.length;i++)
            Book b=new Book();
            b.setName(books[i]);
            b.setPrice(Double.parseDouble(prices[i]));
            //※完成两个值对象的“一对多”关系的数据封装
            s.getBooks().add(b);//一方
            b.setS(s);//多方
        
        //3调用service层
        try 
            service.save(s);
         catch (Exception e) 
            //导向失败页面
        

    


    @Override
    public void execute(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException 
        System.out.println("默认方法");