javax.servlet.jsp
            jsp-api
            2.2
            provided
        

在webapp包下床创建文件hello.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


  
Hello world
    <%
        System.out.println("hello jsp");
    %>

JSP的原理

JSP=HTML+Java 用于简化开发JSP本质上就是ServletJSP在被访问时，由JSP容器（Tomcat）将其转换成java文件（Servlet），在由JSP容器（Tomcat）将其编译，最终对外提供服务的就是这个字节码文件
JSP的脚本

package com.web.web;

public class Brand {
    private int id;
    private String name;

    public Brand(int i, String name) {
        this.id=i;
        this.name=name;
    }


}

package com.web.web;

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;
import java.util.ArrayList;
import java.util.List;

@WebServlet("/ser1")
public class ServletDemo1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.准备数据
        List brands=new ArrayList();
        brands.add(new Brand(1,"三只松鼠"));
        brands.add(new Brand(2,"康师傅"));
        brands.add(new Brand(3,"华为"));

        //存储到request域中
        req.setAttribute("brands",brands);

        //转发
        req.getRequestDispatcher("el-demo.jsp").forward(req,resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    



    ${brands}

1、快速入门

        
            jstl
            jstl
            1.2
        
        
            taglibs
            standard
            1.1.2
        

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


    



    <%--
        c:if:来完成逻辑判断  替换java中的if else
    --%>
    
        
true
   --%>

    
       
false
   --

用转发方式打开

package com.web.web;

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;
import java.util.ArrayList;
import java.util.List;

@WebServlet("/ser1")
public class ServletDemo1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.准备数据
        List brands=new ArrayList();
        brands.add(new Brand(1,"三只松鼠"));
        brands.add(new Brand(2,"康师傅"));
        brands.add(new Brand(3,"华为"));

        //存储到request域中
        req.setAttribute("brands",brands);
        req.setAttribute("status",1);

        //转发
        //req.getRequestDispatcher("el-demo.jsp").forward(req,resp);
        req.getRequestDispatcher("jstl-if.jsp").forward(req,resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


    



    <%--
        c:if:来完成逻辑判断  替换java中的if else
    --%>
<%--    --%>
<%--        
true
--%>
<%--    --%>

<%--    --%>
<%--        
false
--%>
<%--    --%>
    
        启用
    
    
        禁用