编程那点事
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>
