代码在修改更新上有一些缺陷，应该先把相应的要修改的部分查询显示显示出来再进行修改。其实完成增删改查的原理与登录注册是一样的。 1.首先建student类。 public class Studentmodel {private int id;private String name;private String grade;private Str

代码在修改更新上有一些缺陷，应该先把相应的要修改的部分查询显示显示出来再进行修改。其实完成增删改查的原理与登录注册是一样的。

1.首先建student类。

public class Studentmodel {
	
	private int id;
	private String name;
	private String grade;
	private String gender;
	private int age;
	private String address;
	
	public int getId() {
	return id;
	}
	public void setId(int id) {
	this.id = id;
	}
	public String getName() {
	return name;
	}
	public void setName(String name) {
	this.name = name;
	}
	public String getGrade() {
	return grade;
	}
	public void setGrade(String grade) {
	this.grade = grade;
	}
	public String getGender() {
	return gender;
	}
	public void setGender(String gender) {
	this.gender = gender;
	}
	public int getAge() {
	return age;
	}
	public void setAge(int age) {
	this.age = age;
	}
	public String getAddress() {
	return address;
	}
	public void setAddress(String address) {
	this.address = address;
	}

}

2.

1)建接口类。

package cn.edu.hpu.service;

import cn.edu.hpu.model.Studentmodel;

public interface Student {
	public boolean addStu(Studentmodel studentmodel);
 public boolean delStu(int id);
 public boolean updStu(int id,Studentmodel studentmodel);
 public Studentmodel selStu(int id);
}
 

2)接口类的实现

package cn.edu.hpu.service;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;

import cn.edu.hpu.model.Studentmodel;
import cn.edu.hpu.util.Util;

public class StudentImpl implements Student {

	@Override
	public boolean addStu(Studentmodel studentmodel) {
	
	boolean flag=false;
	String sql="insert into student1(id,name,grade,gender,age,address) value(?,?,?,?,?,?)";
	Connection conn=Util.getConnection();
	PreparedStatement pst;
	try {
	pst = conn.prepareStatement(sql);
	pst.setInt(1, studentmodel.getId());
	pst.setString(2, studentmodel.getName());
	pst.setString(3, studentmodel.getGrade());
	pst.setString(4, studentmodel.getGender());
	pst.setInt(5, studentmodel.getAge());
	pst.setString(6, studentmodel.getAddress());
	pst.executeUpdate();
	flag=true;
	} catch (SQLException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
	}
	return flag;
	}

	@Override
	public boolean delStu(int id) {
	
	boolean flag=false;
	String sql="delete from student1 where id="+id;
	Connection conn=Util.getConnection();
	try {
	PreparedStatement pst=conn.prepareStatement(sql);
	pst.executeUpdate();
	flag=true;
	} catch (SQLException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
	}
	return flag;
	}

	@Override
	public boolean updStu(int id, Studentmodel studentmodel) {
	
	boolean flag=false;
	String sql="update student1 set id=?,name=?,grade=?,gender=?,age=?,address=? where id="+id;
	Connection conn=Util.getConnection();
	PreparedStatement pst;
	try {
	pst = conn.prepareStatement(sql);
	pst.setInt(1, studentmodel.getId());
	pst.setString(2, studentmodel.getName());
	pst.setString(3,studentmodel.getGrade());
	pst.setString(4, studentmodel.getGender());
	pst.setInt(5, studentmodel.getAge());
	pst.setString(6, studentmodel.getAddress());
	pst.executeUpdate();
	flag=true;
	} catch (SQLException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
	}
	return flag;
	}

	@Override
	public Studentmodel selStu(int id) {
	Studentmodel studentmodel=new Studentmodel();
	String sql="select * from student1 where id=?";
	Connection conn=Util.getConnection();
	try {
	PreparedStatement pst=conn.prepareStatement(sql);
	pst.setInt(1,id);
	ResultSet rs=pst.executeQuery();
	while(rs.next()){
	//遍历结果集
	studentmodel.setId(rs.getInt("id"));
	studentmodel.setName(rs.getString("name"));
	studentmodel.setGrade(rs.getString("grade"));
	studentmodel.setGender(rs.getString("gender"));
	studentmodel.setAge(rs.getInt("age"));
	studentmodel.setAddress(rs.getString("address"));
	}
	} catch (SQLException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
	}
	// TODO Auto-generated method stub
	return studentmodel;
	}

}

3.建立每个接口方法的servlet。

1）添加的servlet

package cn.edu.hpu.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.edu.hpu.model.Studentmodel;
import cn.edu.hpu.service.Student;
import cn.edu.hpu.service.StudentImpl;

public class tianjia extends HttpServlet {


	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	public void doGet(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
	doPost(request,response);
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
	
	request.setCharacterEncoding("utf-8");
	int Id = Integer.parseInt(request.getParameter("id"));
 String Name=request.getParameter("name");
 String Grade=request.getParameter("grade");
 String Gender=request.getParameter("gender");
 int Age=Integer.parseInt(request.getParameter("age"));
 String Address=request.getParameter("address");
 
 Studentmodel studentmodel=new Studentmodel();
 studentmodel.setId(Id);
 studentmodel.setName(Name);
 studentmodel.setGrade(Grade);
 studentmodel.setGender(Gender);
 studentmodel.setAge(Age);
 studentmodel.setAddress(Address);
 
 Student stu=new StudentImpl();
 boolean flag=stu.addStu(studentmodel);
 if(flag){
 	StudentDaoServlet s=new StudentDaoServlet();
 	s.doPost(request, response);
 }
	}
}

2）删除的servlet。

package cn.edu.hpu.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.edu.hpu.model.Studentmodel;
import cn.edu.hpu.service.Student;
import cn.edu.hpu.service.StudentImpl;

public class shanchu extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;


	public void doGet(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
 doPost(request,response);
	}

	
	public void doPost(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
	
	request.setCharacterEncoding("UTF-8");
	int Id=Integer.parseInt(request.getParameter("id"));
 
	Studentmodel studentmodel=new Studentmodel();
	studentmodel.setId(Id);
	
	Student stu=new StudentImpl();
	boolean flag=stu.delStu(Id);
	if(flag){
	StudentDaoServlet s=new StudentDaoServlet();
	s.doPost(request, response);
	}
	}
}

3）更新的servlet。

package cn.edu.hpu.servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.edu.hpu.model.Studentmodel;
import cn.edu.hpu.service.Student;
import cn.edu.hpu.service.StudentImpl;

public class gengxin extends HttpServlet {
	
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
 doPost(request,response);
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {
 request.setCharacterEncoding("UTF-8");
 int Id=Integer.parseInt(request.getParameter("id"));
 String Name=request.getParameter("name");
 String Grade=request.getParameter("grade");
 String Gender=request.getParameter("gender");
 int Age=Integer.parseInt(request.getParameter("age"));
 String Address=request.getParameter("address");
 
 Studentmodel studentmodel=new Studentmodel();
 studentmodel.setId(Id);
 studentmodel.setName(Name);
 studentmodel.setGrade(Grade);
 studentmodel.setGender(Gender);
 studentmodel.setAge(Age);
 studentmodel.setAddress(Address);
 
 Student stu=new StudentImpl();
 boolean flag=stu.updStu(Id, studentmodel);
 if(flag){
 	StudentDaoServlet s=new StudentDaoServlet();
 	s.doPost(request, response);
 }
 
 }
}

4）查询的servlet。

以上即完成了增删改查的操作。

4. 建jsp页面。这是登录注册完成后跳转到的页面。有添加，删除，修改，查询的超链接，点击后跳转到相应页面可以进行相应的操作。

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>



 可以 
 
	
	

 
 
 
 
 
欢迎你！<%=session.getAttribute("username") %>
 
欢迎登陆教务处系统
 
 
 
添加

 
 
删除

 
 
更新


 
查找
 
 
 
 

 
 	

 	

 	
ID：
 	
Name：
 	
Grade：
 	
Gender:
 	
Age:
 	
Address:
 	
 	

 	
${studentmodel.id }
 	 
${studentmodel.name }
 	
${studentmodel.grade }
 	
${studentmodel.gender}
 	
${studentmodel.age}
 	
${studentmodel.address}
 	
 	
 	
 

 <%@include file="/Page.jsp" %>
 
 
 
 
 

至此完成了增删改查的相应操作。