【复习】servlet之cookie

1，cookie 是存储计算机客户端上的文件，还有保留了跟踪文件信息
2，cookie 在servlet中的使用：首页客户端脚本向浏览器发送一组cookie，浏览器会把这组cookie保存在本地，当下一次使用时，浏览器会把这组cookie发送到服务器，服务器会把这信息用来识别用户。

3,代码如下：

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");
    //创建2个cookie 对象
    Cookie cookieName=new Cookie("name", name);
    Cookie cookieAge=new Cookie("age", age);
    //设置cookie保存的时间 一天时间
    cookieName.setMaxAge(60*60*24);
    cookieAge.setMaxAge(60*60*24);
    //在响应客户端之前保存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,打开浏览器查看：