1,cookie 是存儲計算機客戶端上的文件,還有保留了跟蹤文件信息
2,cookie 在servlet中的使用:首頁客戶端腳本向瀏覽器發送一組cookie,瀏覽器會把這組cookie保存在本地,當下一次使用時,瀏覽器會把這組cookie發送到服務器,服務器會把這信息用來識別用戶。
3,代碼如下:
package com.cookie;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CookieDemo extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
public void init() throws ServletException {
super.init();
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name=request.getParameter("name");
String age=request.getParameter("age");
//創建2個cookie 對象
Cookie cookieName=new Cookie("name", name);
Cookie cookieAge=new Cookie("age", age);
//設置cookie保存的時間 一天時間
cookieName.setMaxAge(60*60*24);
cookieAge.setMaxAge(60*60*24);
//在響應客戶端之前保存cookie
response.addCookie(cookieName);
response.addCookie(cookieAge);
response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
PrintWriter out= response.getWriter();
out.println("cookie ="+request.getCookies()+"<br>");
out.println("name="+request.getParameter("name")+",age="+request.getParameter("age"));
Cookie[] c1=request.getCookies();
out.println("cookie name:"+c1[0].getName()+"<br>");
out.println("cookie name:"+c1[1].getName()+"<br>");
out.println("cookie name:"+c1[0].getValue()+"<br>");
out.println("cookie name:"+c1[1].getValue()+"<br>");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
@Override
public void destroy() {
super.destroy();
}
}
4,配置web.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
id="WebApp_ID" version="3.1">
<display-name>servlet_06_cookie</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>
<!-- 主要配置 -->
<servlet>
<servlet-name>cookie</servlet-name>
<servlet-class>com.cookie.CookieDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>cookie</servlet-name>
<url-pattern>/CookieDemo</url-pattern>
</servlet-mapping>
</web-app>
5,打開瀏覽器查看: