在web.xml定义,在网页中使用变量实例 使用只有创建变量的servlet才可以访问的方式 附带登陆和跳转实现
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//import com.sun.corba.se.spi.protocol.ForwardException;
//import com.sun.jmx.snmp.Enumerated;
public class InitParamServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public InitParamServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setCharacterEncoding("UTF-8");
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out
.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>请登陆查看Notice文件</TITLE></HEAD>");
out.println("<style>body, td, div {font-size:12px;}</style>");
out.println(" <BODY>");
out.println(" <form action='" + request.getRequestURI()
+ "' method='post'>");
out
.println("账号:<input type='text' name='username' style='width=200px;'><br/>");
out
.println("密码:<input type='password' name='password' style='width=200px;'><br/>");
out.println("<input type='submit' value='登陆'>");
out.println(" </form>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to
* post.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
Enumeration params = this.getInitParameterNames();
while(params.hasMoreElements())
{
String usernameParam = (String)params.nextElement();
String passwordParam = getInitParameter(usernameParam);
if(usernameParam.equalsIgnoreCase(username)&&passwordParam.equalsIgnoreCase(password))
{
request.getRequestDispatcher("/WEB-INF/notice.html").forward(request,response);
return;
}
}
this.doGet(request, response);
/*response.setContentType("text/html");
PrintWriter out = response.getWriter();
out
.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(" This is ");
out.print(this.getClass());
out.println(", using the POST method");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();*/
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException
* if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>InitParamServlet</servlet-name>
<servlet-class>com.helloweenvsfei.servlet.InitParamServlet</servlet-class>
<init-param>
<param-name>helloween</param-name>
<param-value>password</param-value>
</init-param>
<init-param>
<param-name>admin</param-name>
<param-value>admin</param-value>
</init-param>
<init-param>
<param-name>babyface</param-name>
<param-value>babyface</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>InitParamServlet</servlet-name>
<url-pattern>/servlet/InitParamServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<login-config>
<auth-method>BASIC</auth-method>
</login-config>
</web-app>