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servlet 3.0无需配置web.xml,使用注入方式配置servlet实现登陆功能(服务器需要支持servlet3.0)

2015-04-04 15:18 866 查看


首先申明上面的报错红叉,我也不知道怎么回事.总之能运行.

新建项目时选择java EE6.0,低版本没有servlet3.0.

先看一个基本示例.

Test.java是用来测试无需配置文件,无需静态页面(jsp,html)

直接访问servlet来从服务器上获取信息.

Test.java代码

package com.gys;

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;

@WebServlet(
name="Test",
urlPatterns={"/test"}
)

public class Test extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doGet(req, resp);
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out=response.getWriter();
out.println("<h1>思思博士</h1>");
}
}


访问结果:



看懂上面的name和urlpattern参数的,继续往下看.

servletConfigDemo.java代码

package com.gys;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@WebServlet(
urlPatterns={"/servletConfigDemo.do"},
loadOnStartup=1,
name="servletConfigDemo",
displayName="demo",
initParams={
@WebInitParam(name="success",value="success.html"),
@WebInitParam(name="error",value="error.html")
}
)
public class servletConfigDemo extends HttpServlet{
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ServletConfig config=getServletConfig();
//1.getInitParameter(name)方法
String success=config.getInitParameter("success");
String error=config.getInitParameter("error");

System.out.println("success-----"+success);
System.out.println("errror------"+error);

//2.getInitParameterNames方法
Enumeration enumeration=config.getInitParameterNames();
while(enumeration.hasMoreElements()){
String name=(String)enumeration.nextElement();
String value=config.getInitParameter(name);
System.out.println("name-----"+name);
System.out.println("value-----"+value);
}

//3getServletContext方法
ServletContext servletContext=config.getServletContext();
System.out.println("servletContext----"+servletContext);

//4.getServletName方法
String servletName=config.getServletName();
System.out.println("servletName------"+servletName);

request.setCharacterEncoding("UTF-8");
String userId=request.getParameter("userId");
String passwd=request.getParameter("passwd");

//判断
if(userId!=null&&"gys".equals(userId)&&passwd!=null&&"gys".equals(passwd)){
HttpSession session=request.getSession();
session.setAttribute("user", userId);
//跳转
RequestDispatcher requestDispatcher=request.getRequestDispatcher(success);
requestDispatcher.forward(request, response);
}
else {
//跳转
RequestDispatcher requestDispatcher=request.getRequestDispatcher(error);
requestDispatcher.forward(request, response);
}

}
}


index.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>登陆</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>

<body>
<form action="servletConfigDemo.do" method="post">
用户名<input type="text" value="" name="userId" /><br/>
密码:<input type="password" name="passwd" />
<input type="submit" value="提交" />
</form>

</body>
</html>


实现登陆功能了
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