Servlet笔记

慕课网学习笔记-Servlet
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1.软件结构发展史

　　1.1单机时代

　　

 　　1.2联机时代（Client-Server模式）

　　

　　1.3互联网时代（Broswer-Server模式）

　　

2.请问与响应、B/S模式执行流程

从浏览器发出送给服务器的数据包称为“请求 Request ”

从服务器返回给浏览器的结果称为“响应 Response ”

　　

 3.J2EE 与 Apache Tomcat

　　

 4.Servlet

　　4.1

　　　　Servlet(Server Applet)服务器小程序，主要功能用于生产动态Web内容

　　4.2　　

　　　　Servlet是J2EE最主要的组成部分，也是我们学习的重点

　　4.3Tomcat与Servlet的关系

　　

5.第一个Servlet

package com.imooc.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FirstServlet extends HttpServlet{
    
    public FirstServlet(){
        System.out.println("正在创建FirstServlet对象");
    }
    
    
    
    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("正在初始化FirstServlet对象");
    }



    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //接收请求发来的参数
        String name = request.getParameter("name");
        String html = "<h1 style='color:red'>hi," + name +"!</h1><hr/>";
        System.out.println("返回给浏览器的响应数据为：" + html);
        PrintWriter out = response.getWriter();
        out.println(html);//将html发送回浏览器
    }



    @Override
    public void destroy() {
        System.out.println("正在销毁servlet对象");  
    }

    
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>FirstServlet</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <!-- 声明Servlet -->
  <servlet>
      <!-- servlet的别名 -->
      <servlet-name>first</servlet-name>
      <servlet-class>com.imooc.servlet.FirstServlet</servlet-class>
  </servlet>
  <!-- 将Servlet与url绑定 -->
  <servlet-mapping>
      <servlet-name>first</servlet-name>
      <url-pattern>/hi</url-pattern>
  </servlet-mapping>
  
   <servlet>
      <!-- servlet的别名 -->
      <servlet-name>sample</servlet-name>
      <servlet-class>com.imooc.servlet.SampleServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>sample</servlet-name>
      <url-pattern>/sample</url-pattern>
  </servlet-mapping>
  
  <servlet>
      <!-- servlet的别名 -->
      <servlet-name>requestMethod</servlet-name>
      <servlet-class>com.imooc.servlet.RequestMethodServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>requestMethod</servlet-name>
      <url-pattern>/request_method</url-pattern>
  </servlet-mapping>
</web-app>

6.标准Java Web工程、Servlet开发步骤

7.Servlet

7.1Servlet访问方法

如：
http://localhost:8080/FirstServlet/anno

7.2请求参数

如：
http://localhost:8080/FirstServlet/sample?name=10086
&mobile=158&sex=male&spec=English&spec=Program&spec=Speech&spec=Swimming

7.3Servlet接收请求参数

 如：

String sex=request.getParameter("sex");
String[] spec=request.getParameterValues("spec");

7.4Get与Post请求方法

Get请求提交的数据，可以在浏览器调试页面的Query String Parameters中查看

Post请求提交的数据，可以在浏览器调试页面的Form Data中查看

Post请求可以用于安全性较高的功能

 

7.5Get与Post处理方式

package com.imooc.servlet;


import java.io.IOException;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class RequestMethodServlet extends HttpServlet{
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException {
        String name=request.getParameter("name");
        response.getWriter().println("<h1 style='color:green'>"+name+"</h1>");
    }
    
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException {
        String name=request.getParameter("name");
        response.getWriter().println("<h1 style='color:red'>"+name+"</h1>");
    }
}

7.6应用场景

 8.Servlet生命周期

 

package com.imooc.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FirstServlet extends HttpServlet{
    
    public FirstServlet(){
        System.out.println("正在创建FirstServlet对象");
    }
    
    
    
    @Override
    public void init(ServletConfig config) throws ServletException {
        System.out.println("正在初始化FirstServlet对象");
    }



    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //接收请求发来的参数
        String name = request.getParameter("name");
        String html = "<h1 style='color:red'>hi," + name +"!</h1><hr/>";
        System.out.println("返回给浏览器的响应数据为：" + html);
        PrintWriter out = response.getWriter();
        out.println(html);//将html发送回浏览器
    }



    @Override
    public void destroy() {
        System.out.println("正在销毁servlet对象");  
    }

    
}

9.使用注解配置Servlet

 

package com.imooc.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;

@WebServlet("/anno")

public class AnnotationServlet extends HttpServlet{

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        resp.getWriter().println("I,m annotation servlet!");
    }
    
}

 10.启动时加载Servlet

package com.imooc.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;


public class CreateServlet extends HttpServlet{

    @Override
    public void init() throws ServletException {
        System.out.println("正在创建数据库");
    }
    
}

package com.imooc.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;

@WebServlet(urlPatterns="/unused",loadOnStartup=12)
public class ImportServlet extends HttpServlet{

    @Override
    public void init() throws ServletException {
        System.out.println("正在导入数据");
    }
    
}

 注解必须，两个参数
@WebServlet(urlPatterns="/unused",loadOnStartup=12)