Servlet中的技術
1.防盜鏈html
String referer = request.getHeader("referer");
if(referer==null || !referer.startsWith("http://localhost")){
response.sendRedirect("/jsp/index.jsp");
return;
}
response.setContentType("text/html;charset=UTF-8");
2.request獲取頭相關的方法java
String value = request.getHeader("Accept-Encoding");
System.out.println(value);
Enumeration e = request.getHeaders("Accept-Encoding");
e = request.getHeaderNames();
while(e.hasMoreElements()){
String name = (String) e.nextElement();
value = request.getHeader(name);
System.out.println(name + "=" + value);
}
3.將請求的類封裝到實體，用到Beanutils類瀏覽器
Map map = request.getParameterMap();
//beanutils
User user = new User();
try {
ConvertUtils.register(new Converter(){
public Object convert(Class type, Object value) {
if(value==null || value.equals("")){
return null;
}
if(!(value instanceof String)){
throw new ConversionException("只支持string類型的轉換！！");
}
String s = (String) value; //9943-348u492
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
try {
return sdf.parse(s);
} catch (ParseException e) {
throw new ConversionException(s + "不是一個合法的日期值");
}
}
}, Date.class);
BeanUtils.populate(user, map); //birthday=1980-09-09
} catch (Exception e) {
e.printStackTrace();
}
4.獲取客戶端提交的表單數據，如select緩存
String likes[] = request.getParameterValues("like");
for(int i=0;likes!=null && i<likes.length;i++){
System.out.println(likes[i]);
}
5.//提交數據的中文亂碼問題cookie
//request.setCharacterEncoding("UTF-8"); //解決post提交的問題
//解決get提交的問題
/*String username = request.getParameter("username");
username = new String(username.getBytes("iso8859-1"),"UTF-8");
System.out.println(username);*/
request.setCharacterEncoding("UTF-8");
String username = request.getParameter("username");
response.setCharacterEncoding("gb2312");
response.setContentType("text/html;charset=gb2312");
response.getWriter().write(username);
//不會亂碼
6//用response的outputStream輸出中文session
//注意事項2
private void test4(HttpServletResponse response)
throws UnsupportedEncodingException, IOException {
response.setHeader("content-type", "text/html;charset=UTF-8");
response.getOutputStream().write((2+"").getBytes("UTF-8"));
}
//注意事項1
private void test3(HttpServletResponse response)
throws UnsupportedEncodingException, IOException {
response.setHeader("content-type", "text/html,charset=UTF-8");
String data = "中國";
byte b[] = data.getBytes("UTF-8");
response.getOutputStream().write(b);
}
//用meta標籤模似一個http響應頭，控制瀏覽器以u8打開
private void test2(HttpServletResponse response)
throws UnsupportedEncodingException, IOException {
//response.setHeader("content-type", "text/html;charset=UTF-8");
String data = "中國";
byte b[] = data.getBytes("UTF-8");
response.getOutputStream().write("<meta http-equiv='content-type' content='text/html;charset=UTF-8'>".getBytes());
response.getOutputStream().write(b);
}
private void test1(HttpServletResponse response)
throws UnsupportedEncodingException, IOException {
response.setHeader("content-type", "text/html;charset=UTF-8");
String data = "中國";
byte b[] = data.getBytes("UTF-8");
response.getOutputStream().write(b);
}
7.//實現文件下載（若是是中文文件名的話，在輸出給客戶機下載時，要記得url編碼）app
String path = this.getServletContext().getRealPath("/download/日本妞.jpg");
String filename = path.substring(path.lastIndexOf("//")+1);
response.setHeader("content-disposition","attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));
FileInputStream in = new FileInputStream(path);
int len = 0;
byte buffer[] = new byte[1024];
OutputStream out = response.getOutputStream();
while((len=in.read(buffer))>0){
out.write(buffer, 0, len);
}
in.close();
8.//控制瀏覽器定時刷新dom
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
System.out.println("登錄成功！！");
this.getServletContext().setAttribute("message", "登錄成功！！本瀏覽器將在3秒後跳到首頁，若是沒有跳轉，請點。。。。。<meta http-equiv='refresh' content='3;url=/day05/index.jsp'>");
this.getServletContext().getRequestDispatcher("/message.jsp").forward(request, response);
/*response.getWriter().write("登錄成功！！<br/>");
response.getWriter().write("本瀏覽器將在3秒後跳到首頁，若是沒有跳轉，請點。。。。。");
response.getWriter().write("<meta http-equiv='refresh' content='3;url=/day05/index.jsp'>");*/
9.//控制瀏覽器緩存jsp
response.setDateHeader("expires", System.currentTimeMillis()+1000*3600);//緩存時間1小時
String data = "xxxxx";
response.getWriter().write(data);
10.驗證碼的技術post
1.
package cn.itcast.checkcode;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImageServlet extends HttpServlet {
private static final int WIDTH = 130;
private static final int HEIGHT = 30;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
setBackground(g);
setBorder(g);
drawRandomLine(g);
String random = drawRandomNum((Graphics2D) g);
request.getSession().setAttribute("checkcode", random); //把驗證碼做爲session傳遞
//response.setHeader("content-type", "image/jpeg");
//Expires: -1
//Cache-Control: no-cache
//Pragma: no-cache
//下面的代碼必定不能少
response.setDateHeader("Expires", -1);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
response.setContentType("image/jpeg");
OutputStream out = response.getOutputStream();
ImageIO.write(image, "jpg", out);
}
private void setBackground(Graphics g) {
g.setColor(Color.WHITE);
g.fillRect(0, 0, WIDTH, HEIGHT);
}
private void setBorder(Graphics g) {
g.setColor(Color.BLUE);
g.drawRect(1, 1, WIDTH-2, HEIGHT-2);
}
private void drawRandomLine(Graphics g) {
g.setColor(Color.GREEN);
for(int i=0;i<5;i++){
int x1 = new Random().nextInt(WIDTH);
int y1 = new Random().nextInt(HEIGHT);
int x2 = new Random().nextInt(WIDTH);
int y2 = new Random().nextInt(HEIGHT);
g.drawLine(x1, y1, x2, y2);
}
}
//[/u4e00-/u9fa5] 30*3.14/180
private String drawRandomNum(Graphics2D g) {
g.setColor(Color.RED);
g.setFont(new Font("宋體",Font.BOLD,20));
String base = "/u7684/u4e00/u4e86/u662f/u6211/u4e0d/u5728/u4eba/u4eec/u6709/u6765/u4ed6/u8fd9/u4e0a/u7740/u4e2a/u5730/u5230/u5927/u91cc/u8bf4/u5c31/u53bb/u5b50/u5f97/u4e5f/u548c/u90a3/u8981/u4e0b/u770b/u5929/u65f6/u8fc7/u51fa/u5c0f/u4e48/u8d77/u4f60/u90fd/u628a/u597d/u8fd8/u591a/u6ca1/u4e3a/u53c8/u53ef/u5bb6/u5b66/u53ea/u4ee5/u4e3b/u4f1a/u6837/u5e74/u60f3/u751f/u540c/u8001/u4e2d/u5341/u4ece/u81ea/u9762/u524d/u5934/u9053/u5b83/u540e/u7136/u8d70/u5f88/u50cf/u89c1/u4e24/u7528/u5979/u56fd/u52a8/u8fdb/u6210/u56de/u4ec0/u8fb9/u4f5c/u5bf9/u5f00/u800c/u5df1/u4e9b/u73b0/u5c71/u6c11/u5019/u7ecf/u53d1/u5de5/u5411/u4e8b/u547d/u7ed9/u957f/u6c34/u51e0/u4e49/u4e09/u58f0/u4e8e/u9ad8/u624b/u77e5/u7406/u773c/u5fd7/u70b9/u5fc3/u6218/u4e8c/u95ee/u4f46/u8eab/u65b9/u5b9e/u5403/u505a/u53eb/u5f53/u4f4f/u542c/u9769/u6253/u5462/u771f/u5168/u624d/u56db/u5df2/u6240/u654c/u4e4b/u6700/u5149/u4ea7/u60c5/u8def/u5206/u603b/u6761/u767d/u8bdd/u4e1c/u5e2d/u6b21/u4eb2/u5982/u88ab/u82b1/u53e3/u653e/u513f/u5e38/u6c14/u4e94/u7b2c/u4f7f/u5199/u519b/u5427/u6587/u8fd0/u518d/u679c/u600e/u5b9a/u8bb8/u5feb/u660e/u884c/u56e0/u522b/u98de/u5916/u6811/u7269/u6d3b/u90e8/u95e8/u65e0/u5f80/u8239/u671b/u65b0/u5e26/u961f/u5148/u529b/u5b8c/u5374/u7ad9/u4ee3/u5458/u673a/u66f4/u4e5d/u60a8/u6bcf/u98ce/u7ea7/u8ddf/u7b11/u554a/u5b69/u4e07/u5c11/u76f4/u610f/u591c/u6bd4/u9636/u8fde/u8f66/u91cd/u4fbf/u6597/u9a6c/u54ea/u5316/u592a/u6307/u53d8/u793e/u4f3c/u58eb/u8005/u5e72/u77f3/u6ee1/u65e5/u51b3/u767e/u539f/u62ff/u7fa4/u7a76/u5404/u516d/u672c/u601d/u89e3/u7acb/u6cb3/u6751/u516b/u96be/u65e9/u8bba/u5417/u6839/u5171/u8ba9/u76f8/u7814/u4eca/u5176/u4e66/u5750/u63a5/u5e94/u5173/u4fe1/u89c9/u6b65/u53cd/u5904/u8bb0/u5c06/u5343/u627e/u4e89/u9886/u6216/u5e08/u7ed3/u5757/u8dd1/u8c01/u8349/u8d8a/u5b57/u52a0/u811a/u7d27/u7231/u7b49/u4e60/u9635/u6015/u6708/u9752/u534a/u706b/u6cd5/u9898/u5efa/u8d76/u4f4d/u5531/u6d77/u4e03/u5973/u4efb/u4ef6/u611f/u51c6/u5f20/u56e2/u5c4b/u79bb/u8272/u8138/u7247/u79d1/u5012/u775b/u5229/u4e16/u521a/u4e14/u7531/u9001/u5207/u661f/u5bfc/u665a/u8868/u591f/u6574/u8ba4/u54cd/u96ea/u6d41/u672a/u573a/u8be5/u5e76/u5e95/u6df1/u523b/u5e73/u4f1f/u5fd9/u63d0/u786e/u8fd1/u4eae/u8f7b/u8bb2/u519c/u53e4/u9ed1/u544a/u754c/u62c9/u540d/u5440/u571f/u6e05/u9633/u7167/u529e/u53f2/u6539/u5386/u8f6c/u753b/u9020/u5634/u6b64/u6cbb/u5317/u5fc5/u670d/u96e8/u7a7f/u5185/u8bc6/u9a8c/u4f20/u4e1a/u83dc/u722c/u7761/u5174/u5f62/u91cf/u54b1/u89c2/u82e6/u4f53/u4f17/u901a/u51b2/u5408/u7834/u53cb/u5ea6/u672f/u996d/u516c/u65c1/u623f/u6781/u5357/u67aa/u8bfb/u6c99/u5c81/u7ebf/u91ce/u575a/u7a7a/u6536/u7b97/u81f3/u653f/u57ce/u52b3/u843d/u94b1/u7279/u56f4/u5f1f/u80dc/u6559/u70ed/u5c55/u5305/u6b4c/u7c7b/u6e10/u5f3a/u6570/u4e61/u547c/u6027/u97f3/u7b54/u54e5/u9645/u65e7/u795e/u5ea7/u7ae0/u5e2e/u5566/u53d7/u7cfb/u4ee4/u8df3/u975e/u4f55/u725b/u53d6/u5165/u5cb8/u6562/u6389/u5ffd/u79cd/u88c5/u9876/u6025/u6797/u505c/u606f/u53e5/u533a/u8863/u822c/u62a5/u53f6/u538b/u6162/u53d4/u80cc/u7ec6";
StringBuffer sb = new StringBuffer();
int x = 10;
for(int i=0;i<4;i++){
String ch = base.charAt(new Random().nextInt(base.length()))+"";
sb.append(ch);
//寫入字以前，設置好旋轉
int degree = new Random().nextInt()%30;
g.rotate(degree*Math.PI/180, x, 20);
g.drawString(ch, x, 20);
g.rotate(-degree*Math.PI/180, x, 20);
x = x+30;
}
return sb.toString();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
2.
request.setCharacterEncoding("UTF-8");
//處理註冊請求以前，校驗認證碼是否有效
String c_checkcode = request.getParameter("checkcode");
String s_checkcode = (String) request.getSession().getAttribute("checkcode");
if(c_checkcode!=null && s_checkcode!=null && c_checkcode.equals(s_checkcode)){
System.out.println("處理註冊請求！！");
}else{
System.out.println("認證碼錯誤！！");
}
11.首頁顯示上次訪問時間
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
//輸出用戶上次訪問時間
out.write("您上次訪問時間是：");
Cookie cookies[] = request.getCookies();
for(int i=0;cookies!=null && i<cookies.length;i++){
Cookie cookie = cookies[i];
if(cookie.getName().equals("lastAccessTime")){
String value = cookie.getValue();
Date d = new Date(Long.parseLong(value));
out.write(d.toLocaleString());
}
}
//輸出本次訪問時間(lastAccessTime)
Cookie cookie = new Cookie("lastAccessTime",System.currentTimeMillis()+"");
cookie.setMaxAge(60*60);
cookie.setPath("/day06");
response.addCookie(cookie);
12.判斷表單是否有效（是否重複提交）
1.
//判斷表單號是否有效
private boolean isTokenValid(HttpServletRequest request) {
String client_token = request.getParameter("token");
if(client_token==null){
return false;
}
String server_token = (String) request.getSession().getAttribute("token");
if(server_token==null){
return false;
}
if(!client_token.equals(server_token)){
return false;
}
return true;
}
2..產生加密的令牌
//產生表單
public class FormServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//產生隨機數（表單號）
TokenProcessor tp = TokenProcessor.getInstance();
String token = tp.generateToken();
request.getSession().setAttribute("token", token);
request.getRequestDispatcher("/form.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
class TokenProcessor{ //令牌
/*
* 1.把構造方法私有
* 2.本身建立一個
* 3.對外暴露一個方法，容許獲取上面建立的對象
*/
private TokenProcessor(){}
private static final TokenProcessor instance = new TokenProcessor();
public static TokenProcessor getInstance(){
return instance;
}
public String generateToken(){
//12121212 232323i23238923892 121232323232323239928392839283829382
String token = System.currentTimeMillis() + new Random().nextInt() + "";
try {
MessageDigest md = MessageDigest.getInstance("md5");
byte[] md5 = md.digest(token.getBytes());
//base64編碼
BASE64Encoder encoder = new BASE64Encoder();
return encoder.encode(md5);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
}
}
}
13..////加上這段把Session提高爲cookie級別，這樣關閉瀏覽器也能瀏覽購買的商品
/*Cookie cookie = new Cookie("JSESSIONID",request.getSession().getId());
cookie.setMaxAge(60*60);
cookie.setPath("/Mybabe");
response.addCookie(cookie);*/
14..對象訪問其餘的域
<title>pageContext對象訪問其它域</title>
</head>
<body>
<%
request.setAttribute("data","aaa");
String data = (String)pageContext.getAttribute("data",PageContext.REQUEST_SCOPE);
out.write(data);
pageContext.findAttribute("data"); //page request session application 重點
%>
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相關文章
- 1. Servlet技術 - Servlet
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