Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之12.Servlet基础(3)

2021-08-26 23:38:36

–提交表单的方法
• get
• post
–Servlet 生命周期
–使用Servlet 输出HTML页面
–获得Servlet初始化参数
–页面导航
• 请求重定向
–response.sendRedirect(“url”);
• 请求转发
–request.getRequestDispatcher(“url”).forward(request,response);
• 请求包含
–request.getRequestDispatcher(“url”).include(request,response);

############Michael分割线################

请求重定向

ServletBasic.java

package com.michael.servlet;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletBasic extends HttpServlet {

 /**
 * Constructor of the object.
 */
 public ServletBasic() {
 super();
 System.out.println("-----ServletBasic-----");
 }

 /**
 * Destruction of the servlet. 
 */
 public void destroy() {
 super.destroy();
 System.out.println("-----destroy-----");
 }

 /**
 * 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 {
 String username = request.getParameter("username");
 String password = request.getParameter("password");
 System.out.println("username="+username);
 response.sendRedirect("http://redking.blog.51cto.com");
 /*
 if(username!=null&&username.equals("redking")){
 request.getRequestDispatcher("/successfull.html").forward(request,response);
 }else{
 request.getRequestDispatcher("/failure.html").forward(request,response);
 }
 */
 /*
 System.out.println("-----doGet-----");

 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();
 */
 }

 /**
 * 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 {
 System.out.println("-----doPost-----");
 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 occure
 */
 public void init() throws ServletException {
 /*
 //第一种方法
 String driver = this.getServletContext().getInitParameter("driver");
 String url = this.getServletContext().getInitParameter("url");
 System.out.println(driver);
 System.out.println(url);
 //第二种方法
 Enumeration enu = this.getServletContext().getInitParameterNames();
 while(enu.hasMoreElements()){
 String name = (String) enu.nextElement();
 String value = this.getServletContext().getInitParameter(name);
 System.out.println(name+":"+value);
 }
 */
 String username = this.getInitParameter("username");
 String password = this.getInitParameter("password");
 System.out.println(username);
 System.out.println(password);
 System.out.println("-----init-----");
 }
 /*
 @Override
 protected void service(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
 // TODO Auto-generated method stub
 System.out.println("-----service-----");
 }
 */
}

Java EE WEB工程师培训-JDBC+Servlet+JSP整合开发之12.Servlet基础(3)

看下效果

重定向了

############Michael分割线################

请求包含

ServletBasic.java

package com.michael.servlet;

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

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ServletBasic extends HttpServlet {

 /**
 * Constructor of the object.
 */
 public ServletBasic() {
 super();
 System.out.println("-----ServletBasic-----");
 }

 /**
 * Destruction of the servlet. 
 */
 public void destroy() {
 super.destroy();
 System.out.println("-----destroy-----");
 }

 /**
 * 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 {
 String username = request.getParameter("username");
 String password = request.getParameter("password");
 System.out.println("username="+username);
 //请求重定向
 //response.sendRedirect("http://redking.blog.51cto.com");
 //请求包含
 PrintWriter out = response.getWriter();
 out.println("This is Servlet Page~~~");
 request.getRequestDispatcher("/successfull.html").include(request,response);
 /*
 //请求转发
 if(username!=null&&username.equals("redking")){
 request.getRequestDispatcher("/successfull.html").forward(request,response);
 }else{
 request.getRequestDispatcher("/failure.html").forward(request,response);
 }
 */
 /*
 System.out.println("-----doGet-----");

 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();
 */
 }

 /**
 * 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 {
 System.out.println("-----doPost-----");
 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 occure
 */
 public void init() throws ServletException {
 /*
 //第一种方法
 String driver = this.getServletContext().getInitParameter("driver");
 String url = this.getServletContext().getInitParameter("url");
 System.out.println(driver);
 System.out.println(url);
 //第二种方法
 Enumeration enu = this.getServletContext().getInitParameterNames();
 while(enu.hasMoreElements()){
 String name = (String) enu.nextElement();
 String value = this.getServletContext().getInitParameter(name);
 System.out.println(name+":"+value);
 }
 */
 String username = this.getInitParameter("username");
 String password = this.getInitParameter("password");
 System.out.println(username);
 System.out.println(password);
 System.out.println("-----init-----");
 }
 /*
 @Override
 protected void service(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
 // TODO Auto-generated method stub
 System.out.println("-----service-----");
 }
 */
}

测试

############Michael分割线################

附件：http://down.51cto.com/data/2353150

本文转自redking51CTO博客，原文链接：http://blog.51cto.com/redking/169230，如需转载请自行联系原作者

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