第一个表单（Head first servlet+Jsp）（实验一）
第一个表单的HTML
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>BeerSel</title>
</head>
<body>
<h1 align="center">Beer Selection Page</h1>
<form method="POST" action="SelectBeer.do">
Select beer charateristics<p>
Color:
<select name="color" size="1">
<option value="light">light</option>
<option value="amber">amber</option>
<option value="brown">brown</option>
<option value="dark">dark</option>
</select>
<br><br>
<center>
<input type="submit">
</center>
</form>
</body>
</html>
2.在开发环境中创建DD
<?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>BeerSelect</display-name>
<welcome-file-list>
<welcome-file>form.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>BeerSelect</servlet-name>
<servlet-class>com.example.web.BeerSelect</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>BeerSelect</servlet-name>
<url-pattern>/SelectBeer.do</url-pattern>
</servlet-mapping>
</web-app>
3.控制器Servlet的第一版
package com.example.web;
import java.io.IOException;
import java.io.PrintWriter;
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 BeerSelect
*/
@WebServlet("/BeerSelect")
public class BeerSelect extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public BeerSelect() {
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
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("Beer Selection advice<br>");
String c = request.getParameter("color");
out.println("<br>got beer color:"+c);
}
}
将项目添加至tomcat，启动tomcat。
在浏览器进行测试。
选择颜色后点击 提交查询
改进这个servlet，让其调用模型
1.创建一个模型类
package com.example.model;
import java.util.ArrayList;
import java.util.List;
public class BeerExpert {
public List getBrands(String color){
List brands = new ArrayList();
if(color.equals("amber")){
brands.add("Jack Amber");
brands.add("Red Moose");
}
else
{
brands.add("Jail Pale Ale");
brands.add("Gout Stout");
}
return(brands);
}
}
2.改进servlet
package com.example.web;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
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.example.model.BeerExpert;
/**
* Servlet implementation class BeerSelect
*/
@WebServlet("/BeerSelect")
public class BeerSelect extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public BeerSelect() {
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
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
String c = request.getParameter("color");
BeerExpert be = new BeerExpert();
List result = be.getBrands(c);
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("Beer Selection advice<br>");
Iterator it = result.iterator();
while(it.hasNext())
{
out.println("<br>try:"+it.next());
}
}
}
测试效果
提交后
改进这个servlet，让其调用JSP返回
1.返回的JSP页面
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.util.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Beer advice</title>
</head>
<body>
<h1 align="center">Beer Recomendations</h1>
<p>
<%
List styles = (List)request.getAttribute("styles");
Iterator it = styles.iterator();
while(it.hasNext()){
out.print("<br>try:"+it.next());
}
%>
</body>
</html>
2.改进后的Servlet
package com.example.web;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;
import javax.servlet.RequestDispatcher;
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.example.model.BeerExpert;
/**
* Servlet implementation class BeerSelect
*/
@WebServlet("/BeerSelect")
public class BeerSelect extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public BeerSelect() {
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
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
String c = request.getParameter("color");
BeerExpert be = new BeerExpert();
List result = be.getBrands(c);
// response.setContentType("text/html");
// PrintWriter out = response.getWriter();
// out.println("Beer Selection advice<br>");
// Iterator it = result.iterator();
// while(it.hasNext())
// {
// out.println("<br>try:"+it.next());
// }
request.setAttribute("styles", result);//为请求对象增加一个属性供JSP使用
RequestDispatcher view = request.getRequestDispatcher("advice.jsp");
//为JSP实例化一个请求分派器
view.forward(request, response);//使用请求分派器要求容器准备好JSP，并向JSP发送请求和响应
}
}
重新启动tomcat
测试结果：
