12. Servlet 데이터 공유

12-1. sevlet parameter

• web.xml (init param) --- getinitParameter() ---> servlet (int param)

 

web.xml

<?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>test</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>
  
  <servlet>
   <servlet-name>servletEx</servlet-name>
   <servlet-class>com.servlet.ServletEx</servlet-class>
   <init-param>
    <param-name>adminId</param-name>
    <param-value>admin</param-value>
   </init-param>
   <init-param>
    <param-name>adminPw</param-name>
    <param-value>1234</param-value>
   </init-param>
  </servlet>
  <servlet-mapping>
   <servlet-name>servletEx</servlet-name>
   <url-pattern>/se</url-pattern>
  </servlet-mapping>
  

</web-app>

 

ServletEx.java

package com.servlet;

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;

public class ServletEx extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		String adminId = getServletConfig().getInitParameter("adminId");
		String adminPw = getServletConfig().getInitParameter("adminPw");
		
		PrintWriter out = response.getWriter();
		out.print("<p>adminId : " + adminId + "</p>");
		out.print("<p>adminPw : " + adminPw + "</p>");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

 

 

12-2. context parameter

 

web.xml

<?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>test</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>
  
  <servlet>
   <servlet-name>servletEx</servlet-name>
   <servlet-class>com.servlet.ServletEx</servlet-class>
   <init-param>
    <param-name>adminId</param-name>
    <param-value>admin</param-value>
   </init-param>
   <init-param>
    <param-name>adminPw</param-name>
    <param-value>1234</param-value>
   </init-param>
  </servlet>
  <servlet-mapping>
   <servlet-name>servletEx</servlet-name>
   <url-pattern>/se</url-pattern>
  </servlet-mapping>
  
  <context-param>
  	<param-name>imgDir</param-name>
  	<param-value>/upload/img</param-value>
  </context-param>
  <context-param>
  	<param-name>testServerIp</param-name>
  	<param-value>127.0.0.1</param-value>
  </context-param>
</web-app>

 

ServletEx.java

package com.servlet;

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;

public class ServletEx extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		String adminId = getServletConfig().getInitParameter("adminId");
		String adminPw = getServletConfig().getInitParameter("adminPw");
		
		PrintWriter out = response.getWriter();
		out.print("<p>adminId : " + adminId + "</p>");
		out.print("<p>adminPw : " + adminPw + "</p>");
        
        String imgDir = getServletContext().getInitParameter("imgDir");
		String testServerIp = getServletContext().getInitParameter("testServerIp");
		
		out.print("<p>imgDir : " + imgDir + "</p>");
		out.print("<p>testServerIp : " + testServerIp + "</p>");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

 

 

12-3. context attribute

 

ServletEx.java

package com.servlet;

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;

public class ServletEx extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		String adminId = getServletConfig().getInitParameter("adminId");
		String adminPw = getServletConfig().getInitParameter("adminPw");
		
		PrintWriter out = response.getWriter();
		out.print("<p>adminId : " + adminId + "</p>");
		out.print("<p>adminPw : " + adminPw + "</p>");
        
        String imgDir = getServletContext().getInitParameter("imgDir");
		String testServerIp = getServletContext().getInitParameter("testServerIp");
		
		out.print("<p>imgDir : " + imgDir + "</p>");
		out.print("<p>testServerIp : " + testServerIp + "</p>");
	
		getServletContext().setAttribute("connectedIP", "165.62.33.33");
		getServletContext().setAttribute("connectedUser", "gildong");
		
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

 

ServletGet.java

package com.servlet;

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("/seg")
public class ServletGet extends HttpServlet {
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String connectedIP = (String) getServletContext().getAttribute("connectedIP");
		String connectedUser = (String) getServletContext().getAttribute("connectedUser");
		
		PrintWriter out = response.getWriter();
		out.print("<p>connectedIP : " + connectedIP  + "</p>");
		out.print("<p>connectedUser : " + connectedUser  + "</p>");
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}