关于Servlet例子

来源：互联网发布：男生哄女生的笑话知乎编辑：程序博客网时间：2024/05/19 07:42

关于Servlet例子

FirstServlet.java

package com.hbsi.csdn.ServletTest;

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 FirstServlet extends HttpServlet{

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doPost(req, resp); //直接调用doPost方法
}

@Override
public void destroy() {
// TODO Auto-generated method stub
super.destroy();
}

@Override
public void init() throws ServletException {
// TODO Auto-generated method stub
super.init();
}

}

SecondServlet.java

package com.hbsi.csdn.ServletTest;

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 SecondServlet extends HttpServlet {

/**
* Constructor of the object.
*/
public SecondServlet() {
super();
}

/**
* Destruction of the servlet. 
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* The doGet method of the servlet. 
*
* 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.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 GET method");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}

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. 
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}

}

ServletConfigTest.java

package com.hbsi.csdn.ServletTest;

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

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 ServletConfigTest extends HttpServlet {

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doPost(req, resp);
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
 throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
PrintWriter out=resp.getWriter();
out.println("<html><body>");
out.println("下面是为servlet设置的初始化参数： servlet的名称是："+getServletName()+" ");
Enumeration e=getServletConfig().getInitParameterNames(); //获取初始化参数的所有名称（枚举类型）
while(e.hasMoreElements()){ //判断集合中是否有更多的元素
 String key=(String)e.nextElement(); //获取集合中的元素
 String value=this.getInitParameter(key); //跟据初始化参数的名称获取初始化参数的值
 out.println("该servlet初始化参数的名称是："+key+" 初始化的值是："+value+" ");
}
ServletContext sc=getServletContext();//获取servletContext对象
String path=sc.getRealPath("/");
out.println("当前应用程序的根目录："+path+" ");

Enumeration e1=sc.getInitParameterNames();
while(e1.hasMoreElements()){
 String key1=(String)e1.nextElement();
 String value1=sc.getInitParameter(key1);
 out.println("该应用程序的初始化参数的名称是："+key1+" 初始化的值是："+value1+" ");
}
out.println("</body></html>");

}

}

ThreadServlet.java

package com.hbsi.csdn.ServletTest;

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 ThreadServlet extends HttpServlet {

private static int count=0;
public ThreadServlet() {
super();
}

/**
* Destruction of the servlet. 
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* The doPost method of the servlet. 
*
* 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 {
count++;
try {
 Thread.sleep(500);
} catch (InterruptedException e) {
 e.printStackTrace();
}
System.out.println("这是第"+count+"次访问，当前的线程名称为："+Thread.currentThread().getName());
}

/**
* Initialization of the servlet. 
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}

}

web.xml

<?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">

<context-param>
<param-name>全局变量</param-name>
<param-value>aaaa</param-value>
</context-param>

<servlet>

<servlet-name>First</servlet-name>

<servlet-class>com.hbsi.csdn.ServletTest.ServletConfigTest</servlet-class>
<init-param>
 <param-name>firstname</param-name>
 <param-value>tom</param-value>
</init-param>
<init-param>
 <param-name>lastname</param-name>
 <param-value>apache</param-value>
</init-param>
</servlet>


<servlet-mapping>

<servlet-name>First</servlet-name>

<url-pattern>/first</url-pattern>
</servlet-mapping>

<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>SecondServlet</servlet-name>
 <servlet-class>com.hbsi.csdn.ServletTest.SecondServlet</servlet-class>
 <load-on-startup>2</load-on-startup>

</servlet>

<servlet>
<servlet-name>ThreadServlet</servlet-name>
<servlet-class>com.hbsi.csdn.ServletTest.ThreadServlet</servlet-class>
</servlet>

<servlet-mapping>
 <servlet-name>SecondServlet</servlet-name>
 <url-pattern>/servlet/SecondServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
 <servlet-name>ThreadServlet</servlet-name>
 <url-pattern>/servlet/ThreadServlet</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>