使用servlet最常见的操作就是页面传值给后台,后台接收处理后台,返回执行结果给前端。接收前端请求的值的方法为:req.getParameter(“输入框的name的名字”);
例子:下面我们从前端传递用户名和密码到后台,后台验证是否正确,然后将结果输出到控制台。前端输入对应的值,就可以测试结果了。
import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet("/login") public class LoginServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 获得用户名 String userName = req.getParameter("userName"); // 获得密码 String userPassword = req.getParameter("userPassword"); if (userName.equals("admin") && userPassword.equals("123456")) { System.out.println("验证通过"); } else { System.out.println("验证失败"); } } }
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>index</title> </head> <body> <form action="/login" method="post"> 用户名:<input type="text" name="userName" /><br> 密码:<input type="password" name="userPassword" /><br> <input type="submit" value="提交" /> </form> </body> </html>