Servlet实现增删改查小案例.docx
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Servlet实现增删改查小案例
MVC模式
ØM:
Model,即模型,对于JavaBean
ØV:
View,即试图,对应JSP页面
ØC:
Controller,即控制器,对应Servlet
1.以下为MVC实现一个简单的增删改查功能
1>显示记录
2>增加一条记录
3>修改一条记录
4>删除一条记录
程序源代码:
M层:
模型层
1.封装一条信息的所有属性JavaBean.java,即VO
packagemuta.bean;
/**
*@authorhelp
*封装一条信息的所有属性
*/
publicclassJavaBean{
privateintid;
privateStringname;
privateStringpassword;
privateStringsex;
privateintage;
publicintgetId(){
returnid;
}
publicvoidsetId(intid){
this.id=id;
}
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
publicStringgetPassword(){
returnpassword;
}
publicvoidsetPassword(Stringpassword){
this.password=password;
}
publicStringgetSex(){
returnsex;
}
publicvoidsetSex(Stringsex){
this.sex=sex;
}
publicintgetAge(){
returnage;
}
publicvoidsetAge(intage){
this.age=age;
}
}
2.封装数据库连接以及操作JavaBean所用到的方法,即DAO
packagemuta.bean;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.PreparedStatement;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.util.ArrayList;
importjava.util.List;
/**
*@authorhelp
*操作数据库的方法
*/
publicclassSqlBean{
Connectioncon;
PreparedStatementpre;
ResultSetrs;
publicSqlBean()
{
try{
Class.forName("com.mysql.jdbc.Driver");
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}
try{
con=DriverManager.getConnection("jdbc:
mysql:
//127.0.0.1:
3306/MyServlet","root","122828");
}catch(SQLExceptione){
e.printStackTrace();
}
}
/**
*@authorhelp
*
*插入新的一条记录
*@return
*/
publicintgetInsert(Stringsql,JavaBeanjBean)
{
intcount=0;
try{
pre=con.prepareStatement(sql);
pre.setString(1,jBean.getName());
pre.setString(2,jBean.getPassword());
pre.setString(3,jBean.getSex());
pre.setInt(4,jBean.getAge());
count=pre.executeUpdate();
}catch(SQLExceptione){
e.printStackTrace();
}
finally
{
try{
pre.close();
con.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}
returncount;
}
/**
*@authorhelp
*
*删除一条记录
*@return
*/
publicintgetDelete(Stringsql,intid)
{
intcount=0;
try{
pre=con.prepareStatement(sql);
pre.setInt(1,id);
count=pre.executeUpdate();
}catch(SQLExceptione){
e.printStackTrace();
}
finally
{
try{
pre.close();
con.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}
returncount;
}
/**
*@authorhelp
*
*根据ID查询某一条记录
*@return
*/
publicJavaBeangetSearchById(Stringsql,intid)
{
JavaBeanjBean=newJavaBean();
try{
pre=con.prepareStatement(sql);
pre.setInt(1,id);
rs=pre.executeQuery();
while(rs.next())
{
jBean.setId(rs.getInt("id"));
jBean.setName(rs.getString("name"));
jBean.setPassword(rs.getString("password"));
jBean.setSex(rs.getString("sex"));
jBean.setAge(rs.getInt("age"));
}
}catch(SQLExceptione)
{
e.printStackTrace();
}
returnjBean;
}
/**
*@authorhelp
*
*更新某一条记录
*@return
*/
publicintgetUpdate(Stringsql,JavaBeanjBean)
{
intcount=0;
try{
pre=con.prepareStatement(sql);
pre.setInt(5,jBean.getId());
pre.setString(1,jBean.getName());
pre.setString(2,jBean.getPassword());
pre.setString(3,jBean.getSex());
pre.setInt(4,jBean.getAge());
count=pre.executeUpdate();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
finally
{
try{
pre.close();
con.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}
returncount;
}
/**
*@authorhelp
*
*显示所有记录
*@return
*/
publicListgetSearch(Stringsql)
{
Listlist=newArrayList();
//获取prepareStatement对象
try{
pre=con.prepareStatement(sql);
rs=pre.executeQuery();
while(rs.next())
{
JavaBeanjBean=newJavaBean();
jBean.setId(rs.getInt("id"));
jBean.setName(rs.getString("name"));
jBean.setPassword(rs.getString("password"));
jBean.setSex(rs.getString("sex"));
jBean.setAge(rs.getInt("age"));
list.add(jBean);
}
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
finally
{
try{
pre.close();
con.close();
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}
returnlist;
}
}
V层:
试图层
1.显示记录集的页面SearchList.jsp
<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%
Stringpath=request.getContextPath();
StringbasePath=request.getScheme()+":
//"+request.getServerName()+":
"+request.getServerPort()+path+"/";
%>
DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
显示记录学生信息如下:
ID | 姓名 | 密码 | 性别 | 年龄 | 操作 |
useBeanid="sBean"class="muta.bean.SqlBean"/>
useBeanid="jBean"class="muta.bean.JavaBean"/>
<%
Stringsql="select*fromstudentorderbyid";
java.util.Listlist=sBean.getSearch(sql);
for(java.util.Iteratorit=list.iterator();it.hasNext();)
{
//获取一个JavaBean对象
jBean=(muta.bean.JavaBean)it.next();
%>
<%=jBean.getId()%> | <%=jBean.getName()%> | <%=jBean.getPassword()%> | <%=jBean.getSex()%> | <%=jBean.getAge()%> | 增加 id=<%=jBean.getId()%>">删除 id=<%=jBean.getId()%>">更新
|
<%}%>
2.插入页面Insert.jsp
<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%
Stringpath=request.getContextPath();
StringbasePath=request.getScheme()+":
//"+request.getServerName()+":
"+request.getServerPort()+path+"/";
%>
DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
插入新值学生管理页面
姓名: | |
密码: | |
性别: | 男 女 |
年龄: | |
|
查询
3.更新页面Update.jsp
<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%
Stringpath=request.getContextPath();
StringbasePath=request.getScheme()+":
//"+request.getServerName()+":
"+request.getServerPort()+path+"/";
%>
DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
更新学生管理页面
学生ID: | "readonly> |
学生姓名: | "> |
学生密码: | "> |
学生性别: | >男 >女 |
学生年龄: | "> |
|
查询
4.出错页面Error.jsp
<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%
Stringpath=request.getContextPath();
StringbasePath=request.getScheme()+":
//"+request.getServerName()+":
"+request.getServerPort()+path+"/";
%>
DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
出错啦!!
!
对不起!
您<%=request.getAttribute("error")%>失败
C层:
控制层—Servlet
1.显示记录集的Servlet----SearchById.java
packagemuta.servlet;
importjava.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importmuta.bean.JavaBean;
importmuta.bean.SqlBean;
publicclassSearchByIdextendsHttpServlet{
privatestaticfinallongserialVersionUID=1L;
/**
*ThedoDeletemethodoftheservlet.
*
*ThismethodiscalledwhenaHTTPdeleterequestisreceived.
*
*@paramrequesttherequestsendbytheclienttotheserver
*@paramresponsetheresponsesendbytheservertotheclient
*@throwsServletExceptionifanerroroccurred