75.【JavaWeb-03】（四）

package Servlet;
import util.Constanta;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
public class LogOut extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session = req.getSession();
        if (session!=null){
            session.removeAttribute(Constanta.USER_SESSION);
            System.out.println("注销成功");
            resp.sendRedirect("http://localhost/Maven_Filter_war_exploded/login.jsp");
        }
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

package com.Jsxs.Filter;
import util.Constanta;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class Demo1 implements Filter {
//    web服务器启动的时候，他就开始初始化了
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("初始化的操作");
    }
//    chain
    /*
        1.过滤中的所有代码，在过滤特定请求的时候都会执行
        2.必须要让过滤器继续同行，就是    chain.doFilter(request,response);
        3.
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=UTF-8");
//        进行强制转换
        HttpServletRequest request1 = (HttpServletRequest) request;
        HttpServletResponse response1 = (HttpServletResponse) response;
//        经过过滤器进行操作
        Object user_session = request1.getSession().getAttribute(Constanta.USER_SESSION);
        if(user_session==null){
            response1.sendRedirect("http://localhost/Maven_Filter_war_exploded/login.jsp");
        }
        chain.doFilter(request,response);   //链的意思: 主要作用就是开启过滤器，如果不写，程序就会被拦截停止
        System.out.println("过滤器正在监听...");
    }
    public void destroy() {
        System.out.println("过滤器已进行销毁");
    }
}

package util;
public class Constanta {
    public final static String USER_SESSION="USER_SESSION";
}

可以在不加main方法的基础上，进行测试输出

junit依赖:
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
junit的附属依赖        
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>

package com.Jsxs;
import org.junit.jupiter.api.Test;
public class Test_Junit {
    @Test
    public void test(){
        System.out.println("hello");
    }
}

1.搭建一个模板项目，然后进行补充和更新目录:，以及Tomcat.
2.测试服务器是否能打开
3.导入项目中会遇到的jar包: servlet, servlet-jsp, mysql,stl,standard
4.建文件目录

4.编写实体类: 实现ORM映射
5.设置数据库配置文件
4.设置过滤器，并且进行配置
6.导入静态数据资源
7.设置首页
8.编写dao层用户登入的接口
9.编写dao接口的实现类

1.阿里巴巴的: fastjson
2.MAVEN
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.61</version>
</dependency>