servlet的Cookie添加、查看、删除

最新推荐文章于 2025-02-17 06:11:37 发布

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最新推荐文章于 2025-02-17 06:11:37 发布

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本文链接：https://blog.youkuaiyun.com/weixin_40873802/article/details/88919938

本文介绍如何在Servlet中使用Java实现Cookie的添加与读取功能。通过示例代码展示了设置Cookie路径及获取并显示Cookie值的方法。

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首先在html中添加两个a标签：添加cookie和读取cookie
< a href = “save”>saveCookie< /a> < br/>
< a href = “read”>readCookie< /a>< br/>

servlet:
1、添加cookie
主要语句：
Cookie cookie1 = new Cookie(“cookie1”,“cookie1’s value”);
resp.add(cookie1); //默认添加的cookie是在当前目录

Cookie cookie2 = new Cookie(“cookie2”,“cookie2’s value”);
cookie2.setPath("/") //相当于所有都可以查看，没有范围可言

public class SavaCookie extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	Cookie cookie1 = new Cookie("cookie1","cookie1's value");
	resp.addCookie(cookie1);
	
	Cookie cookie2 = new Cookie("cookie2","cookie2's value");
	cookie2.setPath("/");
	resp.addCookie(cookie2);
	
	Cookie cookie3 = new Cookie("cookie3","cookie3's value");
	cookie3.setPath("/temp/");
	resp.addCookie(cookie3);
	resp.sendRedirect("index.html");
	
}

2、读取cookie
主要代码：
Cookie[] cookies = req.getCookies();
StringBuilder sb = new StringBuilder(“Cookie的信息：”);
for(Cookie c:cookies){
sb.append("< li>").append(c.getName()).append("–>").append(c.getValue()).append("< /li>");
resp.setContentType(“text/html;charset=UTF-8”);
resp.getWriter().write(sb.toString());
}

代码：

public class ReadCookie extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	req.setCharacterEncoding("UTF-8");
	Cookie[] cookies = req.getCookies();
	StringBuilder sb = new StringBuilder("Cookie信息：");
	for(Cookie c :cookies){
		sb.append("<li>").append(c.getName()).append("->").append(c.getValue()).append("</li>");
	}
	resp.setContentType("text/html;charset=UTF-8");
	resp.getWriter().write(sb.toString());
	
}
@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req,resp);
	}
}

web.xml:

<servlet>
  <servlet-name>saveservlet</servlet-name>
  <servlet-class>com.sy.SavaCookie</servlet-class>
  </servlet>
  <servlet-mapping>
  <servlet-name>saveservlet</servlet-name>
  <url-pattern>/save</url-pattern>
  </servlet-mapping>
  
  <servlet>
  <servlet-name>readservlet</servlet-name>
  <servlet-class>com.sy.ReadCookie</servlet-class>
  </servlet>
  <servlet-mapping>
  <servlet-name>readservlet</servlet-name>
  <url-pattern>/read</url-pattern>
  </servlet-mapping>