操作許可權的控制
阿新 • • 發佈：2018-12-29
上傳檔案往往都必須登陸後才可以進行操作，以前我們已經講過上傳，註冊登陸但是並沒有將它們聯絡在一起，今天主要就是設定許可權只有登陸成功後才可以上傳檔案。
1、原本的介面如圖所示：不用登陸便可以上傳
2、給它加上條件
<c:choose> <c:when test="${empty sessionScope.user_name }"> <form action="${pageContext.request.contextPath}/tishi.jsp" enctype="multipart/form-data" method="post"> <input id="submit" type="submit" value="提交" > </form> </c:when> <c:otherwise> <form action="${pageContext.request.contextPath}/uploadservlet" enctype="multipart/form-data" method="post"> <input id="submit" type="submit" value="提交" > </form> </c:otherwise> </c:choose>
當登入成功了才可以進行操作，否則，會跳轉到提示登陸的介面
這裡需要注意的是sessionScope.user_name對應的是login的servlet裡放到內建物件的變數名
3、因為jsp使用<c:choose>標籤來控制內容顯示，所以，引用
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>故必須新增jstl.jar和standard.jar兩個架包
4、jsp完整的程式碼及截圖如下所示
（1）目錄結構：
（2）login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="${pageContext.request.contextPath}/LoginServlet" method="post" class="" role="form"> username<input type="username" name="username" class="" id="username" placeholder="請輸入使用者名稱..."> password<input type="password" name="password" class="" id="password" placeholder="請輸入密碼..."> <span style="color:red">${msg }</span> <input type="submit"> </form> <a href="upload.jsp">現在去上傳檔案</a> </body> </html>
(3)upload.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<c:choose>
<c:when test="${empty sessionScope.user_name }"> 注意：藍色字型部分對應的是login的serverlet類中的藍色字型部分。
因為用的choose標籤，故必須加入引用語句：即紅色字型部分。
(4)其他的為各類提示介面，這裡就不做詳細的講解了。
message.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
${msg}
</body>
</html>注意：${msg}獲取內建物件名為msg的變數的值，對應servlet類中的紫色字型部分
tishi.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html>
<head>
<title>訊息提示</title>
<link rel="stylesheet" type="text/css" href="css/help.css"/>
<script type="text/javascript">
window.onload=function(){
function addzero(num){
if(num>=10)
{ return ""+num;
}
else
{return "0"+num;
}
}
function times(){
var date=new Date();
var aTime=document.getElementById('aTime');
var str= addzero(date.getHours())+":"+ addzero(date.getMinutes())+":"+ addzero(date.getSeconds());
aTime.innerHTML=str;
}
setInterval(times,1000);
times();
}
</script>
</head>
<body>
<div id="tab">
<h1 id="aTime"></h1>
</div>
<h1>您還沒有登陸，請先去登陸</h1>
<h1><a href="login.jsp">登陸</a></h1>
</body>
</html>5、web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>web_test</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>demo.web.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>uploadservlet</display-name>
<servlet-name>uploadservlet</servlet-name>
<servlet-class>com.sunlizhen.upload.uploadservlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>uploadservlet</servlet-name>
<url-pattern>/uploadservlet</url-pattern>
</servlet-mapping>
</web-app>6、servlet編寫
uploadservlet.jsp
package com.sunlizhen.upload;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class uploadservlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//得到上傳檔案的儲存目錄，將上傳的檔案存放於WEB-INF目錄下，不允許外界直接訪問，保證上傳檔案的安全
String savePath = "E://上傳//";
/* String savePath = this.getServletContext().getRealPath("/WEB-INF/upload");*/
/*String savePath = this.getServletContext().getContextPath();*/
File file = new File(savePath);
//判斷上傳檔案的儲存目錄是否存在
if (!file.exists() && !file.isDirectory()) {
System.out.println(savePath+"目錄不存在，需要建立");
//建立目錄
file.mkdir();
}
//訊息提示
String message = "";
try{
//使用Apache檔案上傳元件處理檔案上傳步驟：
//1、建立一個DiskFileItemFactory工廠
DiskFileItemFactory factory = new DiskFileItemFactory();
//2、建立一個檔案上傳解析器
ServletFileUpload upload = new ServletFileUpload(factory);
//解決上傳檔名的中文亂碼
upload.setHeaderEncoding("UTF-8");
//3、判斷提交上來的資料是否是上傳表單的資料
if(!ServletFileUpload.isMultipartContent(request)){
//按照傳統方式獲取資料
return;
}
//4、使用ServletFileUpload解析器解析上傳資料，解析結果返回的是一個List<FileItem>集合，每一個FileItem對應一個Form表單的輸入項
List<FileItem> list = upload.parseRequest(request);
for(FileItem item : list){
//如果fileitem中封裝的是普通輸入項的資料
if(item.isFormField()){
String name = item.getFieldName();
//解決普通輸入項的資料的中文亂碼問題
String value = item.getString("UTF-8");
//value = new String(value.getBytes("iso8859-1"),"UTF-8");
System.out.println(name + "=" + value);
}else{//如果fileitem中封裝的是上傳檔案
//得到上傳的檔名稱，
String filename = item.getName();
System.out.println(filename);
if(filename==null || filename.trim().equals("")){
continue;
}
//注意：不同的瀏覽器提交的檔名是不一樣的，有些瀏覽器提交上來的檔名是帶有路徑的，如： c:\a\b\1.txt，而有些只是單純的檔名，如：1.txt
//處理獲取到的上傳檔案的檔名的路徑部分，只保留檔名部分
filename = filename.substring(filename.lastIndexOf("\\")+1);
//獲取item中的上傳檔案的輸入流
InputStream in = item.getInputStream();
//建立一個檔案輸出流
FileOutputStream out = new FileOutputStream(savePath + "\\" + filename);
//建立一個緩衝區
byte buffer[] = new byte[1024];
//判斷輸入流中的資料是否已經讀完的標識
int len = 0;
//迴圈將輸入流讀入到緩衝區當中，(len=in.read(buffer))>0就表示in裡面還有資料
while((len=in.read(buffer))>0){
//使用FileOutputStream輸出流將緩衝區的資料寫入到指定的目錄(savePath + "\\" + filename)當中
out.write(buffer, 0, len);
}
//關閉輸入流
in.close();
//關閉輸出流
out.close();
//刪除處理檔案上傳時生成的臨時檔案
item.delete();
message = "檔案上傳成功！";
}
}
}catch (Exception e) {
message= "檔案上傳失敗！";
e.printStackTrace();
}
request.setAttribute("msg",message);
request.getRequestDispatcher("/message.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}LoginServlet.jsp
package demo.web.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet {
static final String driverClassName = "com.mysql.jdbc.Driver";
static final String url = "jdbc:mysql://localhost:3306/test?characterEncoding=utf-8";
static final String mysqlUsername = "root";
static final String mysqlPassword = "slzslz";
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
Class.forName(driverClassName);
conn = DriverManager.getConnection(url, mysqlUsername, mysqlPassword);
String username = request.getParameter("username");
String password = request.getParameter("password");
String sql = "SELECT * FROM sign WHERE username=? and password=?";
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username);
pstmt.setString(2, password);
rs = pstmt.executeQuery();
System.out.println(username +", " + password);
if(rs.next()) {
request.setAttribute("username", rs.getString("username"));
request.getSession().setAttribute("user_name", username);
/*System.out.println(rs.getString("username"));*/
request.setAttribute("msg", "成功登陸！");
request.getRequestDispatcher("/message.jsp").forward(request, response);
} else {
request.setAttribute("msg", "使用者名稱或密碼不正確！");
request.getRequestDispatcher("/login.jsp").forward(request,
response);
}
} catch(Exception e) {
throw new RuntimeException(e);
} finally {
try {
if(conn != null) conn.close();
if(pstmt != null) pstmt.close();
if(conn != null) conn.close();
} catch(Exception e) {
throw new RuntimeException(e);
}
}
}
}