1.hello1代码分析
hello.java
package javaeetutorial.hello1;
import javax.enterprise.context.RequestScoped;#导入了一个java包，注解类型为RequestScoped（（1）指定bean是请求范围的 (2) 请求范围处于活动状态 (3）请求上下文被销毁）
import javax.inject.Named;#导入了一个java包，注解类型为Named（常用于命名注解javax.inject.Name并 javax.enterprise.context.RequestScoped使用请求范围将类标识为托管bean。范围定义应用程序数据如何保持和共享)
@Named
@RequestScoped
#使用两个注解
public class Hello {#定义一个公共类
private String name;#一个私有字符串name
public Hello() { #定义自身类对象
}
public String getName() {定义对象getName，返回name
return name;
}
public void setName(String user_name) {#将setNaame设置为返回值对象，把user_name赋值给this.name
this.name = user_name;
}
}
hello.1.web.xml
<?xml version="1.0" encoding="UTF-8"?>#xml版本号和编码
<web-app version="3.1" #web-app版本号
xmlns="http://xmlns.jcp.org/xml/ns/javaee" #表示web.xml命名空间
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" #类url
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">#指定web.xml约束文件xsd所在位置
<context-param>#表明应用范围内的初始化参数
<param-name>javax.faces.PROJECT_STAGE</param-name>#将参数名为faces的包导入project_stage
<param-value>Development</param-value>#参数值
</context-param>
<servlet>#在向servlet或JSP页面制定初始化参数或定制URL时，必须首先命名servlet或JSP页面。
<servlet-name>Faces Servlet</servlet-name>#servlet命名
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>#指定servlet类包
<load-on-startup>1</load-on-startup>#启动负载为1
</servlet>
<servlet-mapping>#更改缺省url
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.xhtml</url-pattern>#指定url参数类型
</servlet-mapping>
<session-config>#指定缺省超时值
<session-timeout>#会话超时为30
30
</session-timeout>
</session-config>
<welcome-file-list>#指示服务器在收到引用一个目录名而不是文件名的URL时，使用的文件
<welcome-file>index.xhtml</welcome-file>#应用index.xhtml文件
</welcome-file-list>
</web-app>
2.hello2代码分析
Responseservlet.java:
package javaeetutorial.hello2; #软件包名为javaeetutorial.hello2
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;
#导入io 和 serverlet相关的各类包
@WebServlet("/response")
#注解WebServerlet 为response
public class ResponseServlet extends HttpServlet {
#定义类ReponseServerlet从HttpServerlet拓展而来
@Override
#注解Override
public void doGet(HttpServletRequest request,
#定义对象doGet ，定义HttpServerletRequest 为request
HttpServletResponse response)
#定义HttpServerResponse 为response
throws ServletException, IOException {
#抛出异常
try (PrintWriter out = response.getWriter()) {
#将response的getWeite方法赋值给PrintWrite的out，response的getWrite方法来自于HttpServletResponse接口方法
String username = request.getParameter("username");
#将request的getParameter方法获得的username赋值给字符串username，requset来自于HttpServerletRequest接口方法
if (username != null && username.length() > 0) {
#当username字符串不为空且username的长度大于0时
out.println("<h2>Hello, " + username + "!</h2>");
#调用out的println打印Hello，和字符串
}
}
}
@Override
public String getServletInfo() {
return "The Response servlet says hello.";
#定义字符串getServerletinfo，返回内容
}
}
GreetingServlet.java:
package javaeetutorial.hello2;
#包名hello2
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
#导入各类需要的资源包
@WebServlet("/greeting")
#注解名greeting
public class GreetingServlet extends HttpServlet {
#拓展类GreetingServlet从HttpServlet接口
@Override
#注解Override
public void doGet(HttpServletRequest request,
HttpServletResponse response)
#同上定义对象 HttpServletRequest名为request，HttpServletResponse名为response
throws ServletException, IOException {
#抛出异常
response.setContentType("text/html");
#定义文本类型为text，html
response.setBufferSize(8192);
#定义缓冲池大小8192
try (PrintWriter out = response.getWriter()) {
out.println("<html lang=\"en\">"
+ "<head><title>Servlet Hello</title></head>");
// then write the data of the response
out.println("<body bgcolor=\"#ffffff\">"
+ "<img src=\"resources/images/duke.waving.gif\" "
+ "alt=\"Duke waving his hand\">"
+ "<form method=\"get\">"
+ "<h2>Hello, my name is Duke. What's yours?</h2>"
+ "<input title=\"My name is: \" type=\"text\" "
+ "name=\"username\" size=\"25\"/>"
+ "<p></p>"
+ "<input type=\"submit\" value=\"Submit\"/>"
+ "<input type=\"reset\" value=\"Reset\"/>"
+ "</form>");
#以上是打印网页页面相关内容
String username = request.getParameter("username");
if (username != null && username.length() > 0) {
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher("/response");
#将response响应赋给dispatcher分发调度
if (dispatcher != null) {
dispatcher.include(request, response);
}
#当匹配到处理请求响应的处理服务时，就返回请求和response.java的响应内容结果
}
out.println("</body></html>");
}
}
@Override
public String getServletInfo() {
return "The Hello servlet says hello.";
#在页面返回响应的文字
}
}
参考链接：
https://www.cnblogs.com/lijianxuan/p/10606299.html
https://www.cnblogs.com/zrj-cdu/p/10631701.html