实验八 JDBC操作数据库
一、实验目的
1. JDBC连接数据库。
2. 对数据库的增删改查操作。
3. 分页操作。
4. 掌握数据库连接及数据处理技术，理解分页技术，掌握一种基本的分页技术。
二、实验内容
1、教材8.12.1节 查询成绩。
2、教材8.12.2节 管理学生成绩。
3、教材8.12.3节 小星星广告网。
三、实验步骤
1.查询成绩
① 实验代码
文件：ch8_1.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<style>
#tom{
font-family:宋体;font-size:28;color:black
}
</style>
<HTML>
<body bgcolor = "#ffccff">
<form action="ch8_2.jsp" id="tom" method="post" >
输入学号或姓名查询成绩：<br>
<input type="text" id="tom" name="mess" /><br>
<input type="submit" id="tom" name="submit" value="按姓名查询"/>
<input type="submit" id="tom" name="submit" value="按学号查询"/>
</form>
</body>
</HTML>文件：ch8_2.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<%@ page import="java.sql.*" %>
<style>
#tom{
font-family:宋体;font-size:18;color:blue
}
</style>
<HTML>
<body bgcolor="#EEDDFF">
<%
request.setCharacterEncoding("utf-8");
String mess = request.getParameter("mess");
mess = mess.trim();
String submit = request.getParameter("submit");
if(mess.length() == 0){
response.sendRedirect("ch8_1.jsp");
return;
}
Connection con=null;
Statement sql;
ResultSet rs;
try{
Class.forName("com.mysql.cj.jdbc.Driver");
}
catch(Exception e){
out.print("<h1>"+e);
}
String url = "jdbc:mysql://localhost:3306/student?"+
"useSSL=false&serverTimezone=CST&characterEncoding=utf-8";
String user ="root";
String password ="1234";
out.print("<table border=1>");
out.print("<tr>");
out.print("<th id=tom width=100>"+"学号");
out.print("<th id=tom width=100>"+"姓名");
out.print("<th id=tom width=50>"+"数学成绩");
out.print("<th id=tom width=50>"+"英语成绩");
out.print("</tr>");
try{
con = DriverManager.getConnection(url,user,password);
sql=con.createStatement();
String SQL = null;
if(submit.contains("姓名")){
SQL = "SELECT * FROM scoreReport where name like '%"+mess+"%'";
}
else if(submit.contains("学号")){
SQL = "SELECT * FROM scoreReport where id='"+mess+"'";
}
rs=sql.executeQuery(SQL);
while(rs.next()) {
out.print("<tr>");
out.print("<td id=tom>"+rs.getString(1)+"</td>");
out.print("<td id=tom>"+rs.getString(2)+"</td>");
out.print("<td id=tom>"+rs.getInt(3)+"</td>");
out.print("<td id=tom>"+rs.getInt(4)+"</td>");
out.print("</tr>") ;
}
out.print("</table>");
con.close();
}
catch(SQLException e) {
out.print("<h1>"+e);
}
%>
</body>
</HTML>② 运行结果
2.管理学生成绩
① 实验代码
文件：context.xml
<?xml version="1.0" encoding="utf-8" ?>
<Context>
<Resource
name = "studentConn"
type ="javax.sql.DataSource"
driverClassName = "com.mysql.cj.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/student?
&serverTimezone=CST&characterEncoding=utf-8"
username ="root"
password ="1234"
maxActive ="5"
maxIdle ="5"
minIdle ="1"
maxWait ="5000"
/>
</Context>文件：ch8_3.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<%@ page import="java.sql.*" %>
<%@ page import="javax.sql.DataSource" %>
<%@ page import="javax.naming.Context" %>
<%@ page import="javax.naming.InitialContext" %>
<style>
#tom{
font-family:宋体;font-size:28;color:black
}
</style>
<%
request.setCharacterEncoding("utf-8");
Connection con=null;
PreparedStatement pre=null;
ResultSet rs;
Context context =new InitialContext();
Context contextNeeded=(Context)context.lookup("java:comp/env");
DataSource ds=
(DataSource)contextNeeded.lookup("studentConn");
try{
con = ds.getConnection();
}
catch(Exception exp){ }
String updateSQL =
"update scoreReport set name =?,mathScore=?,englishScore=? where id=?";
String insertSQL ="insert into scoreReport values(?,?,?,?)";
String deleteSQL ="delete from scoreReport where id =?";
String querySQL = "select * from scoreReport where id =?";
String mess = request.getParameter("submit");
if(mess == null) mess ="";
String id = request.getParameter("id");
String name = request.getParameter("name");
String math = request.getParameter("mathScore");
String english = request.getParameter("englishScore");
try{
if(mess.contains("查看")){
pre = con.prepareStatement(querySQL);
pre.setString(1,id);
rs = pre.executeQuery();
if(rs.next()){
id = rs.getString(1);
name = rs.getString(2);
math = rs.getString(3);
english = rs.getString(4);
}
}
else if(mess.contains("更新")){
pre = con.prepareStatement(updateSQL);
pre.setString(1,name);
pre.setInt(2,Integer.parseInt(math));
pre.setInt(3,Integer.parseInt(english));
pre.setString(4,id);
pre.executeUpdate();
out.print("<h3>更新成功</h3>");
}
else if(mess.contains("添加")){
pre = con.prepareStatement(insertSQL);
pre.setString(1,id);
pre.setString(2,name);
pre.setInt(3,Integer.parseInt(math));
pre.setInt(4,Integer.parseInt(english));
pre.executeUpdate();
out.print("<h3>添加成功</h3>");
}
else if(mess.contains("删除")){
pre = con.prepareStatement(deleteSQL);
pre.setString(1,id);
pre.executeUpdate();
out.print("<h3>删除成功</h3>");
}
con.close();//连接放回连接池。
}
catch(SQLException e) {
out.print("<h1>学号不能重复");
try{
con.close();//连接放回连接池。
}
catch(SQLException exp){}
}
%>
<HTML>
<body bgcolor = "#ffccff">
<form action="" id="tom" method="post">
输入学号查看或删除（信息）：<br>
<input type="text" id="tom" name="id" size=10 /><br>
<input type="submit" id="tom" name="submit" value="查看"/>
<input type="submit" id="tom" name="submit" value="删除"/>
</form>
<form action="" id="tom" method="post">
更新（或添加）
<input type="text" id="tom" name="id" value =<%=id%> size=9 />
学号的信息：
<br>姓名:
<input type="text" id="tom" name="name" value ='<%=name%>'size=11/>
<br>数学成绩:
<input type="text" id="tom" name="mathScore" value ='<%=math%>'size=7 />
<br>英语成绩:
<input type="text" id="tom" name="englishScore" value ='<%=english%>'size=7/>
<br><input type="submit" id="tom" name="submit" value="更新"/>
<input type="submit" id="tom" name="submit" value="添加"/>
</form>
</body>
</HTML>② 运行结果
3.小星星广告网
① 实验代码
文件：context2.xml
<?xml version="1.0" encoding="utf-8" ?>
<Context>
<Resource
name = "adverConn"
type ="javax.sql.DataSource"
driverClassName = "com.mysql.cj.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/adertisement?
&serverTimezone=CST&characterEncoding=utf-8"
username ="root"
password ="1234"
maxActive ="15"
maxIdle ="15"
minIdle ="1"
maxWait ="1000"
/>
</Context>文件：head.jsp
<style>
#jerry{
font-family:隶书;font-size:58;color:blue;
}
#tom{
font-family:楷体;font-size:33;color:blue;
}
</style>
<div align="center">
<p id=jerry>小星星广告网</p>
<table width="600" align="center" border="0" >
<tr valign="bottom">
<td id=tom><a href="register.jsp">注册</a></td>
<td id=tom><a href="login.jsp">登录</a></td>
<td id=tom><a href="publishAdver.jsp">发布广告</a></td>
<td id=tom><a href="browseAdver.jsp">浏览广告</a></td>
<td id=tom><a href="index.jsp">主页</a></td>
</tr>
</table>
</div>文件：index.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<title>小星星广告网</title>
<HEAD><%@ include file="head.txt" %></HEAD>
<style>
#ok{
font-family:楷体;font-size:50;color:green
}
</style>
<HTML>
<body bgcolor ="pink">
<center id ="ok">
欢迎注册，发布广告。
</center>
</body>
</HTML>文件：web.xml
<?xml version="1.0" encoding="utf-8"?>
<web-app>
<servlet>
<servlet-name>registerServlet</servlet-name>
<servlet-class>handle.data.HandleRegister</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>registerServlet</servlet-name>
<url-pattern>/registerServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>loginServlet</servlet-name>
<servlet-class>handle.data.HandleLogin</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginServlet</servlet-name>
<url-pattern>/loginServlet</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>upFile</servlet-name>
<servlet-class>handle.data.UpFile</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>upFile</servlet-name>
<url-pattern>/upFile</url-pattern>
</servlet-mapping>
</web-app>文件：register.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<jsp:useBean id="userBean" class="save.data.Register" scope="request"/>
<HEAD><%@ include file="head.txt" %></HEAD>
<title>注册页面</title>
<style>
#ok{
font-family:宋体;font-size:26;color:black;
}
</style>
<HTML>
<body id="ok" bgcolor ="cyan">
<form action="registerServlet" id=ok method="post">
用户名由字母、数字、下划线构成，*注释的项必须填写。<br>
*用户名称:<input type=text id=ok name="logname" /><br>
*用户密码:<input type=password id=ok name="password"/><br>
*重复密码:<input type=password id=ok name="again_password"/><br>
<input type=submit id=ok value="提交"><tr>
</form>
注册反馈：
<jsp:getProperty name="userBean" property="logname"/>
<jsp:getProperty name="userBean" property="backNews" />
</body>
</HTML>文件：Register.java
package save.data;
public class Register{
String logname="",
backNews="请输入注册信息";
public void setLogname(String logname){
this.logname=logname;
}
public String getLogname(){
return logname;
}
public void setBackNews(String backNews){
this.backNews=backNews;
}
public String getBackNews(){
return backNews;
}
}文件：Encrypt.java
package handle.data;
public class Encrypt {
static String encrypt(String sourceString,String password) {
char [] p= password.toCharArray();
int n = p.length;
char [] c = sourceString.toCharArray();
int m = c.length;
for(int k=0;k<m;k++){
int mima=c[k]+p[k%n];
c[k]=(char)mima;
}
return new String(c);
}
}文件：HandleRegister.java
package handle.data;
import save.data.Register;
import java.sql.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.DataSource;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class HandleRegister extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
public void service(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException {
request.setCharacterEncoding("utf-8");
Connection con =null;
PreparedStatement sql=null;
Register userBean=new Register();
request.setAttribute("userBean",userBean);
String logname=request.getParameter("logname").trim();
String password=request.getParameter("password").trim();
String again_password=request.getParameter("again_password").trim();
if(logname==null)
logname="";
if(password==null)
password="";
if(!password.equals(again_password)) {
userBean.setBackNews("两次密码不同，注册失败，");
RequestDispatcher dispatcher=
request.getRequestDispatcher("register.jsp");
dispatcher.forward(request, response);
return;
}
boolean isLD=true;
for(int i=0;i<logname.length();i++){
char c=logname.charAt(i);
if(!(Character.isLetterOrDigit(c)||c=='_'))
isLD=false;
}
boolean boo=logname.length()>0&&password.length()>0&&isLD;
String backNews="";
try{ Context context = new InitialContext();
Context contextNeeded =
(Context)context.lookup("java:comp/env");
DataSource ds=
(DataSource)contextNeeded.lookup("adverConn");
con= ds.getConnection();
String insertCondition="INSERT INTO user VALUES (?,?)";
sql=con.prepareStatement(insertCondition);
if(boo){
sql.setString(1,logname);
password =
Encrypt.encrypt(password,"javajsp");
sql.setString(2,password);
int m=sql.executeUpdate();
if(m!=0){
backNews="注册成功";
userBean.setBackNews(backNews);
userBean.setLogname(logname);
}
}
else {
backNews="信息填写不完整或名字中有非法字符";
userBean.setBackNews(backNews);
}
con.close();
}
catch(SQLException exp){
backNews="该会员名已被使用，请您更换名字"+exp;
userBean.setBackNews(backNews);
}
catch(NamingException exp){
backNews="没有设置连接池"+exp;
userBean.setBackNews(backNews);
}
finally{
try{
con.close();
}
catch(Exception ee){}
}
RequestDispatcher dispatcher=
request.getRequestDispatcher("register.jsp");
dispatcher.forward(request, response);
}
}文件：login.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<jsp:useBean id="loginBean" class="save.data.Login" scope="session"/>
<HEAD><%@ include file="head.txt" %></HEAD>
<title>登录页面</title>
<style>
#tom{
font-family:宋体;font-size:30;color:black;
}
</style>
<HTML>
<body id="tom" bgcolor ="pink">
<form action="loginServlet" method="post">
登录用户:<input type="text" id="tom" name="logname" size=12><br>
输入密码:<input type="password" id="tom" name="password" size=12><br>
<input type="submit" id="tom" value="提交"><br>
登录反馈信息:<br>
登录名称:<br><jsp:getProperty name="loginBean" property="logname"/>
<jsp:getProperty name="loginBean" property="backNews"/>
</form>
</body>
</HTML>文件：Login.java
package save.data;
import java.util.*;
public class Login {
String logname="",
backNews="未登录";
public void setLogname(String logname){
this.logname = logname;
}
public String getLogname(){
return logname;
}
public void setBackNews(String s) {
backNews = s;
}
public String getBackNews(){
return backNews;
}
}文件：HandleLogin.java
package handle.data;
import save.data.*;
import java.sql.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.DataSource;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class HandleLogin extends HttpServlet{
public void init(ServletConfig config) throws ServletException{
super.init(config);
}
public void service(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
request.setCharacterEncoding("utf-8");
Connection con =null;
Statement sql;
String logname=request.getParameter("logname").trim(),
password=request.getParameter("password").trim();
password = Encrypt.encrypt(password,"javajsp");
boolean boo=(logname.length()>0)&&(password.length()>0);
try{
Context context = new InitialContext();
Context contextNeeded=
(Context)context.lookup("java:comp/env");
DataSource ds=
(DataSource)contextNeeded.lookup("adverConn");
con= ds.getConnection();//使用连接池中的连接。
String condition="select * from user where logname = '"+
logname+"' and password ='"+password+"'";
sql=con.createStatement();
if(boo){
ResultSet rs=sql.executeQuery(condition);
boolean m=rs.next();
if(m==true){
//调用登录成功的方法:
success(request,response,logname,password);
RequestDispatcher dispatcher=
request.getRequestDispatcher("login.jsp");
dispatcher.forward(request,response);
}
else{
String backNews="您输入的用户名不存在，或密码不般配";
//调用登录失败的方法:
fail(request,response,logname,backNews);
}
}
else{
String backNews="请输入用户名和密码";
fail(request,response,logname,backNews);
}
con.close();
}
catch(SQLException exp){
String backNews=""+exp;
fail(request,response,logname,backNews);
}
catch(NamingException exp){
String backNews="没有设置连接池"+exp;
fail(request,response,logname,backNews);
}
finally{
try{
con.close();
}
catch(Exception ee){}
}
}
public void success(HttpServletRequest request,
HttpServletResponse response,
String logname,String password) {
Login loginBean=null;
HttpSession session=request.getSession(true);
try{ loginBean=(Login)session.getAttribute("loginBean");
if(loginBean==null){
loginBean=new Login();
session.setAttribute("loginBean",loginBean);
loginBean=(Login)session.getAttribute("loginBean");
}
String name =loginBean.getLogname();
if(name.equals(logname)) {
loginBean.setBackNews(logname+"已经登录了");
loginBean.setLogname(logname);
}
else { //数据模型存储新的登录用户:
loginBean.setBackNews(logname+"登录成功");
loginBean.setLogname(logname);
}
}
catch(Exception ee){
loginBean=new Login();
session.setAttribute("loginBean",loginBean);
loginBean.setBackNews(""+ee);
loginBean.setLogname(logname);
}
}
public void fail(HttpServletRequest request,
HttpServletResponse response,
String logname,String backNews) {
response.setContentType("text/html;charset=utf-8");
try {
PrintWriter out=response.getWriter();
out.println("<html><body>");
out.println("<h2>"+logname+"登录反馈结果<br>"+backNews+"</h2>") ;
out.println("返回登录页面或主页<br>");
out.println("<a href =login.jsp>登录页面</a>");
out.println("<br><a href =index.jsp>主页</a>");
out.println("</body></html>");
}
catch(IOException exp){}
}
}文件：publishAdver.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<HEAD><%@ include file="head.txt" %></HEAD>
<title>发布广告页面</title>
<style>
#tom{
font-family:宋体;font-size:26;color:black;
}
</style>
<HTML>
<body id ="tom" bgcolor="#FFBBFF">
选择要上传的文件：<br>
<form action="upFile" method="post" ENCTYPE="multipart/form-data">
<input type="FILE" name="file" id ="tom" size="45"><br>
<input type="submit" id ="tom" name ="submit" value="提交">
</form>
</body>
</HTML>文件：UpFile.java
package handle.data;
import save.data.Login;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class UpFile extends HttpServlet{
public void init(ServletConfig config) throws ServletException{
super.init(config);
}
public void service(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
String backMess ="";
request.setCharacterEncoding("utf-8");
Login loginBean=null;
HttpSession session=request.getSession(true);
String fileName=null;
try{
loginBean = (Login)session.getAttribute("loginBean");
if(loginBean==null){
response.sendRedirect("login.jsp");
return;
}
else {
boolean b =loginBean.getLogname()==null||
loginBean.getLogname().length()==0;
if(b){
response.sendRedirect("login.jsp");
return;
}
}
}
catch(Exception exp){
response.sendRedirect("login.jsp");
return;
}
try{
String tempFileName=(String)session.getId();
String webDir = request.getContextPath();
webDir = webDir.substring(1);
File f= new File("");
String path = f.getAbsolutePath();
int index = path.indexOf("bin");
String tomcatDir = path.substring(0,index);
File dir=new File(tomcatDir+"/webapps/"+webDir+"/image");
dir.mkdir();//建立目录。
File fileTemp=new File(dir,tempFileName);
RandomAccessFile randomWrite = new RandomAccessFile(fileTemp,"rw");
InputStream in=request.getInputStream();
byte b[]=new byte[10000];
int n;
while( (n=in.read(b))!=-1){
randomWrite.write(b,0,n);
}
randomWrite.close();
in.close();
RandomAccessFile randomRead=new RandomAccessFile(fileTemp,"r");
int second=1;
String secondLine=null;
while(second<=2) {
secondLine=randomRead.readLine();
second++;
}
int position=secondLine.lastIndexOf("=");
fileName=secondLine.substring(position+2,secondLine.length()-1);
randomRead.seek(0);
long forthEndPosition=0;
int forth=1;
while((n=randomRead.readByte())!=-1&&(forth<=4)){
if(n=='\n'){
forthEndPosition=randomRead.getFilePointer();
forth++;
}
}
byte cc[]=fileName.getBytes("iso-8859-1");
fileName=new String(cc,"utf-8");
fileName =(loginBean.getLogname()).concat(fileName);
File fileUser= new File(dir,fileName);
randomWrite = new RandomAccessFile(fileUser,"rw");
randomRead.seek(randomRead.length());
long endPosition=randomRead.getFilePointer();
long mark=endPosition;
int j=1;
while((mark>=0)&&(j<=6)) {
mark--;
randomRead.seek(mark);
n=randomRead.readByte();
if(n=='\n'){
endPosition=randomRead.getFilePointer();
j++;
}
}
randomRead.seek(forthEndPosition);
long startPoint=randomRead.getFilePointer();
while(startPoint<endPosition-1){
n=randomRead.readByte();
randomWrite.write(n);
startPoint=randomRead.getFilePointer();
}
randomWrite.close();
randomRead.close();
backMess ="上传成功";
fileTemp.delete();
}
catch(Exception ee) {
backMess ="没有选择文件或上传失败";
}
response.setContentType("text/html;charset=utf-8");
try {
PrintWriter out=response.getWriter();
out.println("<html><body>");
out.println("<h2>"+loginBean.getLogname()+":"+backMess+"</h2>") ;
out.println("<br>返回主页");
out.println("<br><a href =index.jsp>主页</a>");
out.println("</body></html>");
}
catch(IOException exp){}
}
} 文件：browseAdver.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<%@ page import="java.sql.*" %>
<%@ page import="javax.sql.DataSource" %>
<%@ page import="javax.naming.Context" %>
<%@ page import="javax.naming.InitialContext" %>
<HEAD><%@ include file="head.txt" %></HEAD>
<title>浏览广告页面</title>
<style>
#tom{
font-family:宋体;font-size:26;color:black;
}
</style>
<HTML>
<body id="tom" bgcolor="#EEDDFF">
<%
Context context = new InitialContext();
Context contextNeeded = (Context)context.lookup("java:comp/env");
DataSource ds = (DataSource)contextNeeded.lookup("adverConn");
Connection con =null;
Statement sql;
ResultSet rs;
try{
con = ds.getConnection();
sql=con.createStatement();
String SQL = "SELECT logname FROM user";//SQL语句。
rs=sql.executeQuery(SQL);
while(rs.next()) {
String logname = rs.getString(1);
out.print("<br><a href = showAdver.jsp?logname="+logname+
">浏览"+logname+"发布的广告</a>");
}
con.close() ;
}
catch(SQLException e) {
out.print("<h1>"+e);
}
finally{
try{
con.close();
}
catch(Exception ee){}
}
%>
</body>
</HTML>文件：showAdver.jsp
<%@ page contentType="text/html" %>
<%@ page pageEncoding = "utf-8" %>
<jsp:useBean id="play" class="save.data.Play" scope="session" />
<HEAD><%@ include file="head.txt" %></HEAD>
<title>浏览广告图</title>
<style>
#textStyle{
font-family:宋体;font-size:16;color:blue
}
</style>
<% request.setCharacterEncoding("utf-8");
%>
<%
String logname = request.getParameter("logname");
String webDir = request.getContextPath();
webDir = webDir.substring(1);
%>
<jsp:setProperty name="play" property="logname" value="<%= logname %>"/>
<jsp:setProperty name="play" property="webDir" value="<%= webDir %>"/>
<jsp:setProperty name="play" property="index" param = "index" />
<HTML>
<center>
<body bgcolor="pink">
<p id=textStyle></p><br><%=play.logname%>的广告：<br>
<image src = image/<jsp:getProperty name="play" property="showImage"/>
width =300 height =200></image><br>
<a href ="?index=<%=play.getIndex()+1 %>&logname=<%= play.logname %>">下一张</a>
<a href ="?index=<%=play.getIndex()-1 %>&logname=<%= play.logname %>">上一张</a>
</body>
<center>
</HTML>文件：Play.java
package save.data;
import java.io.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class Play {
public String logname;
String pictureName[];
public String showImage;
public String webDir="D:\apache-tomcat-8.5.87\webapps\ch8_1\WEB-INF"; //web服务目录的名字。
public String tomcatDir;
int index = 0;
public Play() {
File f= new File("");
String path = f.getAbsolutePath();
int index = path.indexOf("bin");
tomcatDir = path.substring(0,index);
}
public void setLogname(String s){
showImage="";
logname = s;
}
public void setWebDir(String s) {
webDir = s;
File dirImage = new File(tomcatDir+"/webapps/"+webDir+"/image");
pictureName = dirImage.list(new FileStartName(logname));
}
public String getShowImage() {
try {
showImage = pictureName[index];
return showImage;
}
catch(Exception exp){
return "flower.jpg";
}
}
public void setIndex(int i) {
index = i;
if(index>=pictureName.length)
index = 0;
if(index < 0)
index = pictureName.length-1;
}
public int getIndex() {
return index ;
}
}
class FileStartName implements FilenameFilter {
String logname=null;
Pattern pattern;
Matcher matcher;
FileStartName(String logname) {
this.logname = logname;
pattern = Pattern.compile(logname);
}
public boolean accept(File dir,String name) {
matcher = pattern.matcher(name);
if(matcher.find())
return true;
else
return false;
}
}② 运行结果
四、实验总结
本次实验应用了MySQL数据库与jsp页面的链接，前两个小实验比较简单，最后一个实验涉及到的页面较多，比较复杂，完成了一整套的小系统。将jsp页面、数据库和Java综合到了一起。
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