–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################
全局参数对全局生效,我们来测试一下
ServletBasic2.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 ServletBasic2 extends HttpServlet {    

        /**    
         * Constructor of the object.    
         */
    
        public ServletBasic2() {    
                super();    
        }    

        /**    
         * Destruction of the servlet. <br>    
         */
    
        public void destroy() {    
                super.destroy(); // Just puts "destroy" string in log    
                // Put your code here    
        }    

        /**    
         * The doGet method of the servlet. <br>    
         *    
         * 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 {    

                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. <br>    
         *    
         * 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 {    

                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. <br>    
         *    
         * @throws ServletException if an error occure    
         */
    
        public void init() throws ServletException {    
                Enumeration enu = this.getServletContext().getInitParameterNames();    
                while(enu.hasMoreElements()){    
                        String name = (String) enu.nextElement();    
                        String value = this.getServletContext().getInitParameter(name);    
                        System.out.println(name+":"+value);    
                }    
        }    

}
测试一下
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–局部参数
• web.xml 配置
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• 获得
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web.xml
<?xml version="1.0" encoding="UTF-8"?>    
<web-app version="2.4"    
        xmlns="http://java.sun.com/xml/ns/j2ee"    
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee    
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">    
        <context-param>    
                <param-name>driver</param-name>    
                <param-value>com.mysql.jdbc.Driver</param-value>    
        </context-param>    
        <context-param>    
                <param-name>url</param-name>    
                <param-value>jdbc:mysql://localhost:3306/jdbc_db</param-value>    
        </context-param>    
    <servlet>    
        <servlet-name>ServletBasic</servlet-name>    
        <servlet-class>com.michael.servlet.ServletBasic</servlet-class>    
        <init-param>    
                <param-name>username</param-name>    
                <param-value>michael</param-value>    
        </init-param>    
        <init-param>    
                <param-name>password</param-name>    
                <param-value>111222</param-value>    
        </init-param>    
    </servlet>    
    <servlet>    
        <servlet-name>ServletBasic2</servlet-name>    
        <servlet-class>com.michael.servlet.ServletBasic2</servlet-class>    
    </servlet>    

    <servlet-mapping>    
        <servlet-name>ServletBasic</servlet-name>    
        <url-pattern>/servlet/ServletBasic</url-pattern>    
    </servlet-mapping>    
    <servlet-mapping>    
        <servlet-name>ServletBasic2</servlet-name>    
        <url-pattern>/servlet/ServletBasic2</url-pattern>    
    </servlet-mapping>    

</web-app>
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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. <br>    
         */
    
        public void destroy() {    
                super.destroy();    
                System.out.println("-----destroy-----");    
        }    

        /**    
         * The doGet method of the servlet. <br>    
         *    
         * 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 {    
                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. <br>    
         *    
         * 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. <br>    
         *    
         * @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-----");    
        }    
}
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ServletBasic2.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 ServletBasic2 extends HttpServlet {    

        /**    
         * Constructor of the object.    
         */
    
        public ServletBasic2() {    
                super();    
        }    

        /**    
         * Destruction of the servlet. <br>    
         */
    
        public void destroy() {    
                super.destroy(); // Just puts "destroy" string in log    
                // Put your code here    
        }    

        /**    
         * The doGet method of the servlet. <br>    
         *    
         * 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 {    

                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. <br>    
         *    
         * 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 {    

                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. <br>    
         *    
         * @throws ServletException if an error occure    
         */
    
        public void init() throws ServletException {    
                /*    
                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);    
        }    

}
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测试
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现在调用第二个
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• 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”).forward(request,response);
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. <br>    
         */
    
        public void destroy() {    
                super.destroy();    
                System.out.println("-----destroy-----");    
        }    

        /**    
         * The doGet method of the servlet. <br>    
         *    
         * 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);    
                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. <br>    
         *    
         * 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. <br>    
         *    
         * @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-----");    
        }    
        */
    
}
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successfull.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">    
<html>    
    <head>    
        <title>successfull.html</title>    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    
        <meta http-equiv="description" content="this is my page">    
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">    
        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->    

    </head>    
    <body>    
        <h1>successfull!!!</h1>    
    </body>    
</html>
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failure.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">    
<html>    
    <head>    
        <title>failure.html</title>    
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">    
        <meta http-equiv="description" content="this is my page">    
        <meta http-equiv="content-type" content="text/html; charset=UTF-8">    
        <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->    

    </head>    
    <body>    
        <h1>failure!!!</h1>    
    </body>    
</html>
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输入用户名为redking进行测试
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显示successfull!!!
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输入其他用户名测试
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显示failure!!!
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看下显示信息
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############Michael分割线################