servlet+jsp数据库增删改查实例
个人觉得这种模式是MVC模式
1. 先写一个类，类里面有几个属性。
2. 写一个接口。里面有增删改查的方法。 （写在service里）
3. 写一个类实现这个接口（实现里面的增删改查等操作） （写在service里）
4. 连接数据库
5. 写 servlet操作， 处理增删改查的信息。
6. Jsp页面 （写页面显示或者上传，添加的页面布局等）与servlet实现交互，从而实现以上功能。
增删改查具体实例如下———— 具体代码：
XinxManager.java
package cn.hpu.service;
importjava.util.List;
importcn.hpu.gu.Xinx;
//定义接口 增删改查，获取表单信息，通过id获取信息等方法
public interfaceXinxManager{
public List
public boolean add(Xinx xin);
public boolean del(String id);
public boolean update( Xinx xin);
public boolean select(String name,Stringpassword);
public Xinx getXinxById(String id);
}
//定义一个类实现这个接口的方法
XinxManagerImp.Java
packagecn.hpu.service;
importjava.sql.Connection;
importjava.sql.ResultSet;
importjava.sql.Statement;
importjava.util.ArrayList;
importjava.util.List;
importcn.hpu.gu.Xinx;
importcn.hpu.util.util;
importcom.mysql.jdbc.PreparedStatement;
public classXinxManagerImp implements XinxManager{
//增加
public boolean add(Xinx xin) {
boolean flag = false;
//定义一个标志，赋值为false
Connection conn = null;
PreparedStatement pst =null;
conn = util.getConnection();
String sql="insert into report(title,speaker ,address ,unit , time,content,dateposted)values(?,?,?,?,?,?,?)";
//几个参数几个问号，这里id设置的是自增的所以没必要添加
try{
conn = util.getConnection();
pst = (PreparedStatement)conn.prepareStatement(sql);
//pst.setString(1, xin.getId());
//pst.setInt(1, xin.getId());
//get所要添加的信息，set到数据库对应的位置
pst.seString(, xin.getTitle());
pst.setString(2, xin.getSpeaker());
pst.setString(3, xin.getAddress());
pst.setString(4, xin.getUnit());
pst.setString(5, xin.getTime().toString());
pst.setString(6, xin.getContent());
pst.setString(7,xin.getDateposted().toString());
//executeUpdate(sql)是更新数据，
//返回int类型是返回的更新了多少行，也就是受影响的行数，如果为0，则表示无更新
int rows = pst.executeUpdate();
if(rows>0)
{
flag=true;
}
}catch (Exception e) {
e.printStackTrace();
}finally{
util.close(pst, conn);
}
return flag; //返回flag方便后面的获取
}
//删除
public boolean del(String id) {
boolean flag = false;
Connection conn = null;
PreparedStatement pst = null;
conn = util.getConnection();
try{
String sql = "delete fromreport where id like?";
pst = (PreparedStatement)conn.prepareStatement(sql);
pst.setString(1, id);
int rows = pst.executeUpdate();
if(rows>0){
flag = true;
}
}catch (Exception e) {
e.printStackTrace();
}finally{
util.close(pst, conn);
}
return flag;
}
//查询
public List
//用到了类型转换 （方法内定义的 public List
List
Connection conn = null;
ResultSet rs = null; //!!!!!!!
Statement stmt = null;
try{
conn = util.getConnection();
String sql = "select * fromreport";
//创建Statement (Sql语句的执行环境)
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
//executeQuery(StringsqlString)执行查询数据库的SQL，
//eg:SELECT语句，返回一个结果集（ResultSet）
while( rs.next()){ //！！！！
Xinx xin = new Xinx();
//查询。类的所有成员信息都set出来
xin.setId(rs.getString("id"));
//解读一下，请求获取 字符串，然后都set出来
xin.setSpeaker(rs.getString("speaker")); xin.setAddress(rs.getString("address"));
xin.setTitle(rs.getString("title"));
xin.setTime(rs.getString("time"));
xin.setContent(rs.getString("content"));
xin.setUnit(rs.getString("unit"));
xin.setDateposted(rs.getString("dateposted"));
list.add(xin); //！！！！！！
}
}catch (Exception e) {
e.printStackTrace();
}finally{
util.close(rs, stmt, conn);
}
return list;
}
//修改
public boolean update(Xinx xin){
boolean flag = false;
Connection conn = null;
java.sql.PreparedStatement pst =null;
conn = util.getConnection();
String sql= "update report settitle=?,speaker=?,address=?,unit=?,time=?,content=?,dateposted=? where id ="+xin.getId(); //where id =?"; (两个是一个意思，自where后的东西，是可以替换的，下面会稍作修改，因为多了一个问号)
try{
pst =conn.prepareStatement(sql);
pst.setString(1,xin.getTitle());
pst.setString(2,xin.getSpeaker());
pst.setString(3,xin.getAddress());
pst.setString(4,xin.getUnit());
pst.setString(5,xin.getTime());
pst.setString(6, xin.getContent());
pst.setString(7,xin.getDateposted());
//如果不加这个会出错（Statement parameter 8 not set.）说为设置，所以如果用问号，那就几个问号，设计几个Statement parameter。
//pst.setString(8, xin.getId());
int rows = pst.executeUpdate();
if(rows>0)
{flag = true;}
}catch (Exception e)
{
e.printStackTrace();
}
finally
{
util.close(pst, conn);
}
return flag;
}
//根据id查询它的所有信息
public Xinx getXinxById(String id) {
Connection conn = null;
ResultSet rs = null;
Statement stmt = null;
Xinx xin = new Xinx();
try{
conn = util.getConnection();
String sql = "select * from report whereid ="+id;
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next())
{
//测试一下看看获取id了木有
System.out.println(rs.getString("id")+"通过id查询信息");
if(rs.getString("id").equals(id)) {
//查询 显示出来
xin.setId(rs.getString("id"));
xin.setTitle(rs.getString("title"));
xin.setSpeaker(rs.getString("speaker"));
xin.setAddress(rs.getString("address"));
xin.setTime(rs.getString("time"));
xin.setContent(rs.getString("content"));
xin.setUnit(rs.getString("unit"));
xin.setDateposted(rs.getString("dateposted"));
}
}
}catch (Exception e)
{
e.printStackTrace();
}finally
{
util.close(rs, stmt, conn);
}
System.out.println(xin.getId());
return xin;
}
public boolean select(String name, Stringpassword) {
// TODO Auto-generated method stub
return false;
}
}
addServlet.java
packagecn.hpu.servlet;
importjava.io.IOException;
importjava.io.PrintWriter;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
importcn.hpu.gu.Xinx;
importcn.hpu.service.XinxManager;
importcn.hpu.service.XinxManagerImp;
public classAddServlet extends HttpServlet {
public void doGet(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
//防止中文乱码，这样最保险
response.setContentType("text/html;chartset=utf-8");
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
// request.getParameter（）获取jsp页面提交的数据
String id = request.getParameter("id");
String title =request.getParameter("title");
String speaker = request.getParameter("speaker");
String address =request.getParameter("address");
String unit =request.getParameter("unit");
String time =request.getParameter("time");
String content =request.getParameter("content");
String dateposted = request.getParameter("dateposted");
Xinx xin = new Xinx();
//xin.setId(0);
xin.setTitle(title);
xin.setSpeaker(speaker);
xin.setAddress(address);
xin.setUnit(unit);
xin.setTime(time);
xin.setContent(content);
xin.setDateposted(dateposted);
XinxManager xm = new XinxManagerImp();
boolean flag = xm.add(xin);
System.out.println("增加这里的"+flag);
if(flag == true )
//跟上面的意思是一样的if(flag)
{
//作用：增加成功后会调到一个页面，显示出来
Xinx xin1 = xm.getXinxById(id);
//通过id获的这组信息，用setAttribute传到表单页面
request.setAttribute("xin1", xin);
//在 login1.jsp显示新添加的信息，这样一目了然
request.getRequestDispatcher("login1.jsp").forward(request,response);
/*或者直接跳到主页面
//request.setAttribute("param","success");
System.out.println("添加成功");
//request.getRequestDispatcher("login.jsp").forward(request,response);
response.setContentType("text/html");
PrintWriter out =response.getWriter();
out.println("");
out.println("");
out.println("
out.println("
");out.println("添加成功！！！");
out.println(" 返回主页面");
out.println(" ");
out.println("");
out.flush();
out.close();
*/
}else {
//request.setAttribute("param","failed");
System.out.println("添加失败");
//如果添加失败转发到原来的页面
request.getRequestDispatcher("add.jsp").forward(request,response);
}
}
}
<%@ page language="java"import="java.util.*,cn.hpu.gu.*" pageEncoding="utf-8"%>
<%
String path =request.getContextPath();
String basePath =request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
Login1.jsp
DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login1.jsp' starting pagetitle>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
head>
<body>
<h3>增加或者修改后的信息 | <a href="login.jsp">返回主界面a> h3>
<table border="1"cellpadding="0" cellspacing="0"width="80%" align="center">
<tr>
<th>题目th>
<th>主讲th>
<th>地址th>
<th>主讲人单位th>
<th>时间th>
<th>内容th>
<th>发布时间th>
<th>操作th>
tr>
<%
// XinxManager xm= new XinxManagerImp();
// List
// if(list!=null)
// {
// for(int i=0; i
// {
// Xinx xin =list.get(i);
Xinx xin =(Xinx)request.getAttribute("xin1");
if(xin!=null)
{
%>
<tr>
<td><%=xin.getTitle() %>td>
<td><%=xin.getSpeaker() %>td>
<td><%=xin.getAddress()%>td>
<td><%=xin.getUnit() %>td>
<td><%=xin.getTime() %>td>
<td><%=xin.getContent() %>td>
<td><%=xin.getDateposted()%>td>
<td>
<a href="DelServlet?id=<%=xin.getId() %>">删除a>
<a href="UpdateServlet1?id=<%=xin.getId() %>">修改a>
td>
tr>
<%
// }
}
%>
table>
body>
html>
DelServlet.Java
packagecn.hpu.servlet;
importjava.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importcn.hpu.service.XinxManager;
importcn.hpu.service.XinxManagerImp;
public classDelServlet extends HttpServlet {
public void doGet(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
String id =request.getParameter("id");
XinxManager xm = new XinxManagerImp();
boolean flag = xm.del(id);
if(flag == true)
{
response.sendRedirect("login.jsp");
}
}
}
Search.java 查询的servlet
packagecn.hpu.servlet;
importjava.io.IOException;
importjava.sql.ResultSet;
importjava.util.List;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
importorg.omg.PortableServer.ForwardRequest;
importcn.hpu.gu.Xinx;
importcn.hpu.service.XinxManager;
importcn.hpu.service.XinxManagerImp;
public classSearch extends HttpServlet {
public void doGet(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequestrequest, HttpServletResponse response)
throws ServletException,IOException {
XinxManager xm = new XinxManagerImp();
List
request.setAttribute("list", list);
//转发
request.getRequestDispatcher("login.jsp").forward(request,response);
}
}
Login.jsp
<%@ page language="java"import="java.util.*,cn.hpu.gu.*" pageEncoding="utf-8"%>
<%@page import="cn.hpu.service.XinxManager"%>
<%@page import="cn.hpu.service.XinxManagerImp"%>
<%
String path =request.getContextPath();
String basePath =request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>管理员操作页面title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
head>
<h2>管理信息h2>
欢迎${sessionScope.loginuser}登陆
<a href="add.jsp">添加学生a> <a href= "index.jsp">退出a>
<hr/>
<body>
<table border="1"cellpadding="0" cellspacing="0"width="80%" align="center">
<tr>
<th>题目th>
<th>主讲th>
<th>地址th>
<th>主讲人单位th>
<th>时间th>
<th>内容th>
<th>发布时间th>
<th>操作th>
tr>
<%
XinxManager xm = new XinxManagerImp();
List
if(list!=null)
{
for(int i=0; i { Xinx xin = list.get(i); %> <tr> <td><%=xin.getTitle() %>td> <td><%=xin.getSpeaker() %>td> <td><%=xin.getAddress()%>td> <td><%=xin.getUnit() %>td> <td><%=xin.getTime() %>td> <td><%=xin.getContent() %>td> <td><%=xin.getDateposted()%>td> <td> <a href="DelServlet?id=<%=xin.getId() %>">删除a> <a href="UpdateServlet1?id=<%=xin.getId() %>">修改a> td> tr> <% } } %> table> body> html> UpdateServlet1.java packagecn.hpu.servlet; importjava.io.IOException; importjavax.servlet.ServletException; importjavax.servlet.http.HttpServlet; importjavax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; importcn.hpu.gu.Xinx; importcn.hpu.service.XinxManager; importcn.hpu.service.XinxManagerImp; public classUpdateServlet1 extends HttpServlet { //通过login.jsp中的修改跳这，（获取数据库中要更改单的信息） public void doGet(HttpServletRequestrequest, HttpServletResponse response) throws ServletException,IOException { this.doPost(request, response); } public void doPost(HttpServletRequestrequest, HttpServletResponse response) throws ServletException,IOException { //通过id获取要修改的信息 String id =request.getParameter("id"); XinxManager xm = new XinxManagerImp(); System.out.println("获取数据库中要更新id的所有信息"+id); //调用XinxManagerImp.java里的方法 Xinx xin = xm.getXinxById(id); if(xin != null) { //通过id获得的xin的信息用setAttribute方法穿到表单中 request.setAttribute("xin",xin); //跳转到更改页面 request.getRequestDispatcher("update.jsp").forward(request,response); } } } update.jsp <%@ page language="java"import="java.util.*,cn.hpu.gu.*" pageEncoding="utf-8"%> <% String path =request.getContextPath(); String basePath =request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>修改页面title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> head> <% //表单中通过getAttribute获取setAttribute 传来的xin的信息 Xinx xin =(Xinx)request.getAttribute("xin"); %> <body> <h1>修改信息h1> <hr/> <form action="UpdateServlet"method="post"> <table> <input name="id" type="text" value="<%=xin.getId()%> " style="display: none;"/> <tr align="left"> <th> 题 目th> <th><input name="title" type="text"value="<%=xin.getTitle()%>">th> tr> <tr align="left"><th> 主 讲th> <th><input name="speaker"type="text" value="<%=xin.getSpeaker() %>">th> tr> <tr align="left"> <th> 地 址th> <th><input name="address"type="text" value="<%=xin.getAddress()%>"> th> tr> <tr align="left"> <th>主讲人单位th> <th><input name="unit"type="text" value="<%=xin.getUnit() %> ">th> tr> <tr align="left"> <th> 时 间th> <th><input name="time"type="date" value="<%=xin.getTime() %> ">th> tr> <tr align="left"> <th> 内 容th> <th ><input name="content"type="text" value=" <%=xin.getContent() %> ">th> tr> <tr align="left"> <th>发布时间th> <th><input name="dateposted" type="date" value=" <%=xin.getDateposted()%>">th> tr> <tr align="left"> <th><input type="submit"value=" 修改" />th> tr> table> form> body> html> UpdateServlet.java packagecn.hpu.servlet; importjava.io.IOException; importjavax.servlet.ServletException; importjavax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; importjavax.servlet.http.HttpServletResponse; importcn.hpu.gu.Xinx; importcn.hpu.service.XinxManager; importcn.hpu.service.XinxManagerImp; public classUpdateServlet extends HttpServlet { //进行数据库中信息修好，也就是重新获取修改后提交的信息 public void doGet(HttpServletRequestrequest, HttpServletResponse response) throws ServletException,IOException { this.doPost(request, response); } public void doPost(HttpServletRequestrequest, HttpServletResponse response) throws ServletException,IOException { response.setContentType("text/html;chartset=utf-8"); response.setCharacterEncoding("utf-8"); request.setCharacterEncoding("utf-8"); //request.getParameter()方法是获取Http(这里是更改表单)提交过来的数据 String id = request.getParameter("id"); String title =request.getParameter("title"); String speaker =request.getParameter("speaker"); String address =request.getParameter("address"); String unit =request.getParameter("unit"); String time = request.getParameter("time"); String content =request.getParameter("content"); String dateposted =request.getParameter("dateposted"); XinxManager xm = newXinxManagerImp(); Xinx xin = new Xinx(); //将新数据set进去。。。 xin.setId(id); xin.setTitle(title); xin.setSpeaker(speaker); xin.setAddress(address); xin.setUnit(unit); xin.setTime(time); xin.setContent(content); xin.setDateposted(dateposted); //调用update(Xinxxin)方法{里面将get的新数据信息，再set到数据库中，从而完成修改} boolean flag = xm.update(xin); System.out.println("修改后提交的信息"+id); if(flag == true) { //例子 //Student stu1 = sm.getStudentById(id); //request.setAttribute("stu1",stu1); Xinx xin1 = xm.getXinxById(id); request.setAttribute("xin1",xin); request.getRequestDispatcher("login1.jsp").forward(request,response); System.out.println(xin.getId()+"9999999999999"); //request.getRequestDispatcher("login.jsp").forward(request,response); }else { } } }