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
}
}
