servlet的Cookie添加、查看、删除

谁借莪１个温暖的怀抱￠ 2022-04-23 15:26 216阅读 0赞

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>