servletcontext的使用总结

1同一个web 应用就能共享配置文件中的servletcontext的<context-para>参数，不是同一个web 应用就不行

2 servletcontext的<context-para>参数值的获取方法

名称为muti的lweb应用

try1.servlet

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class try1 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html; charset=gb2312");

PrintWriter out = response.getWriter();

//获取属性值

String val=this.getServletContext().getInitParameter("user");

if(val!=null)

{

System.out.print(val);

out.println("获取属性值:"+val);

}

else

{

out.println("获取属性值:"+val);

out.println("不是同一个web就不能获取");

}

}

}

名称为cookies1的lweb应用

share1.java

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class share1 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html; charset=gb2312");

PrintWriter out = response.getWriter();

//获取属性值

String val=this.getServletContext().getInitParameter("user");

System.out.print(val);

out.println("获取属性值:"+val);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// response.setContentType("text/html");

//PrintWriter out = response.getWriter();

}

}

servletcontext2.java

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class servletcontext2 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html; charset=gb2312");

PrintWriter out = response.getWriter();

ServletContext Servletcontext2=this.getServletContext();//获得ServletContext对象

String val1=(String)Servletcontext2.getAttribute("user");

out.println(val1);

out.println("分隔开");

String val=this.getServletContext().getInitParameter("user");

System.out.print(val);

out.println("获取属性值:"+val);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

//response.setContentType("text/html");

//PrintWriter out = response.getWriter();

}

}