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  • JavaWeb_通过xml配置文件配置servlet访问路径

    Servlet两种访问路径

    　　

    　　一、在Servlet类中通过设置@WebServlet标注访问

    　　二、在web.xml中编写配置文件

    　　第一种能比较直观看到Servlet路径，但当项目发布后不好再对Servlet路径进行修改

    　　第二种把Servlet路径在web.xml中配置， 能更好对Servlet路径进行配置的修改

    　　

    　　利用Servlet处理注册登录请求　　传送门

    　　项目结构

    　　

    package com.Gary.servlet;

import java.io.IOException;

import javax.servlet.ServletContext;
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 com.Gary.model.User;
import com.Gary.util.DBUtil;


@WebServlet("/login_do")
public class LoginServlet extends HttpServlet {
   
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        User user = DBUtil.verifyAccount(username,password);
        if(user==null){
//            out.println("登录失败，用户名或密码错误");
            request.setAttribute("message","登录失败，用户名或密码错误");
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
//            out.println("登录成功");
            int number = 0;
            //获取到application对象
            ServletContext application = this.getServletContext();
            //第一次登录用户时if不瞒住,number=0
            if(application.getAttribute("userNumber")!=null){
                number = (Integer)application.getAttribute("userNumber");
            }
            
            //登录过一个用户后在原基础number上进行++
            number++;

            application.setAttribute("userNumber",number);
            
            //通过seesion的setAttribute传递数据
            request.getSession().setAttribute("user", user);
            //登录请求的转发,将数据传递给personCenter.jsp页面
            request.getRequestDispatcher("personCenter.jsp").forward(request,response);
        }
    }

}
    LoginServlet.java
    package com.Gary.servlet;

import java.io.IOException;
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 com.Gary.util.DBUtil;


//@WebServlet("/register_do")
public class RegisterServlet extends HttpServlet {

    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        int age = Integer.parseInt(request.getParameter("age"));
        String sex = request.getParameter("sex");

        boolean isSuccess = DBUtil.addUser(username,password,age,sex);

        //使用请求转发
        if(isSuccess){
            request.setAttribute("message", "注册成功，请登录");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
            request.setAttribute("message", "注册失败，用户名重复");
            //通过getRequestDispatcher传递路径将请求转发给login.jsp
            request.getRequestDispatcher("register.jsp").forward(request,response);
        }
        
    }

}
    RegisterServlet.java
    <%@page import="com.Gary.model.User"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
Object o = session.getAttribute("user");
if(o!=null){
    User user = (User)o;
    out.println("当前登录用户："+user.getUsername()+"<br/>");
}
%>

<%
Object msg = request.getAttribute("message");
if(msg!=null)
    out.println(msg);
%>

登录<hr>
<form action="login_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
<input type="submit" value="登录" />
</form>
</body>
</html>
    login.jsp
    <%@page import="com.Gary.model.User"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
Object o = session.getAttribute("user");
if(o!=null){
    User user = (User)o;
    out.println("当前登录用户："+user.getUsername()+"<br/>");
}
%>

<%
Object msg = request.getAttribute("message");
if(msg!=null)
    out.println(msg);
%>

<form action="register_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
年龄：<input type="text" name="age" /><br/>
性别： 男<input type="radio" name="sex" value="男" />女<input type="radio" name="sex" value="女" /><br/>
<input type="submit" value="注册" />
</form>

</body>
</html>
    register.jsp
    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
  version="3.1"
  metadata-complete="true">
  <!-- 配置servlet -->
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.Gary.servlet.LoginServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>com.Gary.servlet.RegisterServlet</servlet-class>
    </servlet>
    
    <!-- servlet路径映射 -->
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/login_do</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/register_do</url-pattern>
    </servlet-mapping>
</web-app>
    web.xml

    　　LoginServlet.java处理login.jsp登录表单的请求

    　　RegisterServlet.java处理register.jsp注册表单的请求　　

    第一种

    　　通过在Servlet上设置@WebServlet标注，容器就会自动读取当中的信息，@WebServlet告诉容器，如果请求的URL是"/xxxxxx"

    　　LoginServlet.java中配置的路径是login_do，在register.jsp的from表单中设置action也为login_do

    　　由LoginServlet.java处理register.jsp的from表单提交的信息

    @WebServlet("/login_do")
public class LoginServlet extends HttpServlet {
   
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        User user = DBUtil.verifyAccount(username,password);
        if(user==null){
//            out.println("登录失败，用户名或密码错误");
            request.setAttribute("message","登录失败，用户名或密码错误");
            request.getRequestDispatcher("login.jsp").forward(request,response);
        }else{
//            out.println("登录成功");
            int number = 0;
            //获取到application对象
            ServletContext application = this.getServletContext();
            //第一次登录用户时if不瞒住,number=0
            if(application.getAttribute("userNumber")!=null){
                number = (Integer)application.getAttribute("userNumber");
            }
            
            //登录过一个用户后在原基础number上进行++
            number++;

            application.setAttribute("userNumber",number);
            
            //通过seesion的setAttribute传递数据
            request.getSession().setAttribute("user", user);
            //登录请求的转发,将数据传递给personCenter.jsp页面
            request.getRequestDispatcher("personCenter.jsp").forward(request,response);
        }
    }

}
    <form action="login_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
<input type="submit" value="登录" />
</form>

    第二种

    　　通过web.xml配置文件进行配置

     　　<servlet-name>中填写项目中Servlet名字　　【可随便填写，用作后边<servlet-mapping>映射url】

    　　<servlet-class>中填写项目中该Servlet路径

    　　<servlet-mapping>配置servlet-name和<url-pattern>地址映射

      <!-- 配置servlet -->
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.Gary.servlet.LoginServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>com.Gary.servlet.RegisterServlet</servlet-class>
    </servlet>
    
    <!-- servlet路径映射 -->
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/login_do</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/register_do</url-pattern>
    </servlet-mapping>

    　　将com.Gary.servlet.LoginServlet路径上的Servlet命名为LoginServlet，与后边<servlet-mapping>中的<servlet-name>LoginServlet相匹配

    　　【按住Ctrl+鼠标左键点击<servlet-class>下的路径可直接访问对应Servlet下的路径】

    (如需转载学习，请标明出处)
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  • 原文地址：https://www.cnblogs.com/1138720556Gary/p/10301094.html
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