servlet

发表于： 2019年10月13日 2019年12月10日
分类： Java

HttpServlet

创建javaweb项目关联tomcat安装目录

java项目目录

JAVA存放目录：SRC
WEB文件目录：WebContent
WEB配置文件：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>javaweb</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>HelloServlet</servlet-name>
    <servlet-class>servlet.HelloServlet</servlet-class>
    <load-on-startup>10</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>HelloServlet</servlet-name>
    <url-pattern>/servlet/HelloSevlet</url-pattern>
  </servlet-mapping>
 
  <servlet>
    <!-- servlet的内部名称，自定义。尽量有意义 -->
    <servlet-name>ServletDemo</servlet-name>
	<!-- servlet的类全名： 包名+简单类名 -->
    <servlet-class>servlet.ServletDemo</servlet-class>
    <load-on-startup>2</load-on-startup>
  </servlet>
  <servlet-mapping>
     <!-- servlet的内部名称，一定要和上面的内部名称保持一致！！ -->
    <servlet-name>ServletDemo</servlet-name>
	 <!-- servlet的映射路径（访问servlet的名称） -->
    <url-pattern>/servlet/ServletDemo</url-pattern>
  </servlet-mapping>
 
</web-app>

welcome-file-list:当用户在浏览器中输入的URL不包含某个servlet名或JSP页面时，welcome-file-list元素可指定显示的默认文件。

javax.servlet.http.HttpServlet方法
• doPost, for HTTP POST requests
• doPut, for HTTP PUT requests
• doDelete, for HTTP DELETE requests
• init and destroy,to manage resources that are held for the life of the servlet
• getServletInfo, which the servlet uses toprovide information about itself

创建一个继承HttpServlet的类

package 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 HelloServlet extends HttpServlet {
 
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		PrintWriter  writer= resp.getWriter(); 
		resp.setContentType("text/html;charset=GBK");
		writer.println("<strong>Hello,222222</strong>");
	}
 
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("处理post请求");
 
	}
}

web.xml配置servlet

  <servlet>
     <servlet-name>HelloServlet</servlet-name>
     <servlet-class>servlet.HelloServlet</servlet-class>
  </servlet>
  <servlet-mapping>
     <servlet-name>HelloServlet</servlet-name>
     <url-pattern>/servlet/HelloSevlet</url-pattern>
  </servlet-mapping>

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