eclipse下javaweb简单servlet调用——javaweb系列(二)
本文目录
本例servlet版本为3.1
新建servlet文件
【src】----【右键 new package】----【命名为servlet】
【servlet】----【右键 new servlet】
点击Finish，完成创建servlet，自动生成以下代码：
package 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;
/**
* Servlet implementation class Test1Servlet
*/
@WebServlet("/Test1Servlet")
public class Test1Servlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Test1Servlet() {
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
doGet(request, response);
}
}
- doGet()方法用来处理通过get提交的表单信息.
- doPost()方法用来处理通过Post提交的表单信息
新建jsp测试servlet
新建test.jsp，代码如下：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="TestServlet" method="post">
账号:<input type="text" name="account" />${accountErrorString }<br>
密码:<input type="password" name="psd" />${psdErrorString }<br>
<input type="submit" value="提交" /><br>${errorString }
</form>
</body>
</html>
新建test1.jsp，验证成功后跳转
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>登录成功</h1>
</body>
</html>
修改servelt文件
@WebServlet("/TestServlet")
public class TestServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @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
// doGet(request, response);
String account = request.getParameter("account");
String psd = request.getParameter("psd");
if(account.equals("admin") && psd.equals("123456")) {
request.getRequestDispatcher("success.jsp").forward(request, response);
}else if(account.equals("admin") && !psd.equals("123456")) {
request.setAttribute("psdErrorString", "password is error");
request.getRequestDispatcher("test.jsp").forward(request, response);
}else if(!account.equals("admin") && psd.equals("123456")) {
request.setAttribute("accountErrorString", "account is error");
request.getRequestDispatcher("test.jsp").forward(request, response);
}else {
request.setAttribute("errorString", "login error");
request.getRequestDispatcher("test.jsp").forward(request, response);
}
}
}
至此完成一个简单的servlet功能。
运行测试
登陆错误显示：
登陆成功显示：
servlet知识集合
servlet版本
-
Servlet3.0以后
提供了注解(annotation)，使得不再需要在web.xml文件中进行Servlet的部署描述，简化开发流程，初始化后自动生成
@WebServlet注解，如上例所示@WebServlet("/TestServlet")也可以使用web.xml进行配置
-
Servlet3.0以下
web.xml中配置
<servlet> <servlet-name>TestServlet</servlet-name> <servlet-class>servlet.TestServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>TestServlet</servlet-name> <url-pattern>/TestServlet</url-pattern> </servlet-mapping>url-pattern必须以/开始，引用时引用url-pattern中/后面的部分
比如/handlerServlet，表单action=“handlerServlet”；
比如/servlet/handlerServlet，表单action=“servlet/handlerServlet”
引用的是url-pattern，不是servlet-name
Servlet跳转到jsp页面
- sendRedirect方式
sendRedirect("/a.jsp"); 可以将页面跳转到任何路径，不局限于web应用中，跳转的过程中url地址变化，无法使用request.setAttribute来传递 - forward方式
request.getRequestDispatcher("/a.jsp").forward(request.response); url地址不变，只能跳转到本web应用中的页面上。可以用request.setAttibute方法
