Java web：jsp，个人注意事项，创建servlet，HTTP协议，学习笔记PPT【诗书画唱】
1、创建一个servlet，调用这个servlet以后要求控制台打印出服务器的时间SimpleDateFormat转换打印出2000-9-16 9:13:16。（个人的注意事项：用快捷方式生成的servlet，不必修改web.xml【自己手建的servlet，要修改web.xml】）
package JSP;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class SimpleDateFormat
*/
@WebServlet("/s")
public class NowTime extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public NowTime() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(HttpServletRequest
request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest
* request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
Date date=new Date();
//这个方法也是需要导包的
//注意第二个mm要大写,不然月份会有错误
SimpleDateFormat sdf=new SimpleDateFormat("yyy-MM-dd hh:mm:ss");
System.out.println(sdf.format(date));
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>ZCJSP</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>
</web-app>
2、创建一个servlet，调用这个servelt以后要求控制台打印出一个随机数。
package JSP;
import java.io.IOException;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Random
*/
@WebServlet("/Random")
public class RandomNum extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public RandomNum() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest
* request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest
* request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
Random R=new Random();
int num=R.nextInt(666);
System.out.println(num);
}
}
3、创建一个servlet，调用这个servlet以后要求控制台打印出hello world。
package JSP;
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;
/**
* Servlet implementation class Hello
*/
@WebServlet("/Hello")
public class Hello extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Hello() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println("hello world");
}
}
4、创建一个servlet，调用这个servlet以后要求控制台打印出今天是星期几。
package JSP;
import java.io.IOException;
import java.util.Calendar;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Week
*/
@WebServlet("/Week")
public class Week extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Week() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,
IOException {
String Array[]={"星期日","星期一","星期二",
"星期三","星期四","星期五","星期六"};//字符串数组
Calendar rightNow=Calendar.getInstance();
/**
* 总结：
* getInstance这个方法在单例模式用的甚多，为了避免对内存造成浪费，
* 直到需要实例化该类的时候才将其实例化，所以用getInstance来获取该对象，
* 至于其他时候，也就是为了简便而已，为了不让程序在实例化对象的时候，
* 不用每次都用new关键字，索性提供一个instance方法，不必一执行这个类就
* 初始化，这样做到不浪费系统资源！单例模式 可以防止 数据的冲突，节省内存空间*/
int XiaBiao=rightNow.get(rightNow.DAY_OF_WEEK);//获取时间
System.out.println("今天是"+Array[XiaBiao-1]);
//通过数组把周几输出
//------------------------------------------------------------
}}
5、创建一个servlet，调用这个servlet以后要求控制台打印出一个九九乘法口诀表。
代码不准写在同一个servlet类中，不准使用注解
package JSP;
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;
/**
* Servlet implementation class NineNine
*/
@WebServlet("/NineNine")
public class NineNine extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public NineNine() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request,
* \ HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException {
// TODO Auto-generated method stub
for(int j=1;j<=9;j++){
for(int i=1;i<=j;i++){System.out.print
(j+"*"+i+"="+i*j+" ");}System.out.println
();
}
}
}
servlet小型应用程序【[ˈsərvlɪt]】
例子：
手动创建一个servlet，运行它的时候在后台打印Hello world.
或按10的步骤鼠标右键等后运行代码：
下面是运行的结果：
用快捷键或快捷方式选项等创建一个servlet：
或者点other后点Servlet：
快捷方式自动生成访问路径，web.xml中的就可以不用写访问路径的部分：
——————
或
运行后：
————————
HTTP协议的get和post的请求方式：
Servlet简介：
关于打开和编辑xml文件的方法：
关于HTTP协议的PPT：
POST 方法
用于发送敏感信息（如信用卡号）或要保存到数据库中的信息
请求的页面不能设置为书签或不能通过电子邮件发送
发送的数据没有大小限制
SERVLET开发入门PPT：
