Tomcat容器
第一个servlet
什么是servlet
Server applet即运行在服务器端的小程序
使用Servlet
package com.asset.sec88539;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;
@WebServlet("/helloServlet")
public class ServletDemo1 implements Servlet {
@Override
public void init(ServletConfig servletConfig) throws ServletException {
}
@Override
public ServletConfig getServletConfig() {
return null;
}
@Override
public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
servletResponse.getWriter().println("ServletDemo1");
}
@Override
public String getServletInfo() {
return "";
}
@Override
public void destroy() {
}
}
使用HttpServlet
import java.io.*;
import javax.servlet.http.*;
public class HelloServlet extends HttpServlet {
private String message;
public void init() {
message = "Hello World!";
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setContentType("text/html");
// Hello
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<h1>" + message + "</h1>");
out.println("</body></html>");
}
public void destroy() {
}
}
web.xml方式配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>com.asset.sec88539.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>
</web-app>
- 注解配置
package com.asset.sec88539;
import java.io.*;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
@WebServlet(name = "HelloServlet", urlPatterns = "/hello")
public class HelloServlet extends HttpServlet {
private String message;
public void init() {
message = "Hello World!";
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setContentType("text/html");
// Hello
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<h1>" + message + "</h1>");
out.println("</body></html>");
}
public void destroy() {
}
}
servlet之间的继承关系
public class HelloServlet extends HttpServlet
public abstract class HttpServlet extends GenericServlet
public abstract class GenericServlet implements Servlet, ServletConfig, Serializable
第一个filter
package com.asset.sec88539;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
@WebFilter("/*")
public class FilterDemo1 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("FilterDemo1");
filterChain.doFilter(servletRequest, servletResponse);
}
@Override
public void destroy() {
}
}
package com.asset.sec88539;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
@WebFilter("/hello")
public class FilterDemo2 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("FilterDemo2");
filterChain.doFilter(servletRequest, servletResponse);
}
@Override
public void destroy() {
}
}
第一个Listener
package com.asset.sec88539;
import javax.servlet.ServletRequest;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.annotation.WebListener;
import java.lang.reflect.Field;
@WebListener()
public class listenerMem implements ServletRequestListener {
@Override
public void requestInitialized(ServletRequestEvent sre) {
ServletRequest req = sre.getServletRequest();
Class reqClass = req.getClass();
try {
Field field = reqClass.getDeclaredField("request");
field.setAccessible(true);
String cmd = req.getParameter("cmd");
if (cmd != null) {
System.out.println("cmd: " + cmd);
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public void requestDestroyed(ServletRequestEvent sre) {
}
}
JSP
什么是JSP
JSP即java sevlet page
三种jsp代码写法与不同
<%= %>
<% %>
<%! %>
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>JSP - Hello World</title>
</head>
<body>
<h1><%= "Hello World!" %>
</h1>
<br/>
<%
System.out.println("index.jsp");//在service中
int i = 5;
%>
<%!
int i = 3; //定义成员变量，成员方法
%>
<%= i %>// 输出语句定义的内容
</body>
</html>
