Request对象获取请求头数据相关方法

getHeaderNames()

作用：获取所有请求头的名字
返回值类型：Enumeration< String>

Enumeration：是个迭代器，有两个方法 hasMoreElements(); nextElement();

getHeader(String name) （重点）

作用：根据请求头的名字，获取其value值
参数name即为请求头的名字
返回值类型：String

测试代码

@WebServlet(name = "RequestDemo2", value = "/requestDemo2")
public class RequestDemo2 extends HttpServlet {
    
    
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //获取所有请求头的名称
        Enumeration<String> headerNames = request.getHeaderNames();
        //遍历
        while (headerNames.hasMoreElements()){
    
    
            String name = headerNames.nextElement();
            //根据请求头的名称获取请求头的值
            String value = request.getHeader(name);
            System.out.println(name+":"+value);
        }

    }
}

结果

host:localhost
connection:keep-alive
cache-control:max-age=0
sec-ch-ua:"Google Chrome";v="111", "Not(A:Brand";v="8", "Chromium";v="111"
sec-ch-ua-mobile:?0
sec-ch-ua-platform:"Windows"
upgrade-insecure-requests:1
user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36
accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
sec-fetch-site:cross-site
sec-fetch-mode:navigate
sec-fetch-user:?1
sec-fetch-dest:document
accept-encoding:gzip, deflate, br
accept-language:zh-CN,zh;q=0.9
cookie:JSESSIONID=BACA32C62CC73505DD0178E34531D21C; _ga=GA1.1.1717905582.1633016465; JSESSIONID=E576986031221D734A3D7882557C867A