马士兵Servlet&JSP(1.Servlet)源代码

[学习笔记]马士兵 Servlet & JSP(1.Servlet) 1.HTTP协议基础测试（获取页面源代码） import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException; /** * HTTP协议基础测试 * 本程序将Tomcat首页的页面源代码拿下来 * 用此方法，我们可以将我们访问到的页面的内容都拿下来 * @author ykn * */public class HttpTest {     public static void main(String[] args) {                Socket s = null;        PrintWriter pw = null;        BufferedReader br = null;                    try {            // 建立连接端口，s指向本地机器tomcat服务器端口上            s = new Socket("127.0.0.1",8888);            // 对于本程序而言是输出，则相当于是准备向tomcat服务器端口写请求            pw = new PrintWriter(new OutputStreamWriter(s.getOutputStream()));            // 请求访问页面（此处等同于访问http://localhost:8888/）                pw.println("GET / HTTP/1.1");            pw.println("Host: www.bjsxt.com");            pw.println("Content-Type:text/html");            pw.println("");            // 上一句表示请求内容结束            pw.flush();            // 上面这一段用于本程序向Tomcat服务器发出访问请求（get）                                    // 服务器端作出响应，对于本程序而言是输入            br = new BufferedReader(new InputStreamReader(s.getInputStream()));            String str = "";            // 将服务器端的响应信息打印输出（即将http://localhost:8888/页面代码源文件中的内容输出）            // 用此方法，我们可以将我们访问到的页面的内容都拿下来            while((str = br.readLine()) != null) {                System.out.println(str);            }                    } catch (UnknownHostException e) {            System.out.println("未知的主机异常。。。");            e.printStackTrace();        } catch (IOException e) {            System.out.println("IO异常。。。");            e.printStackTrace();        } finally {            try {                if (br != null) {                    br.close();                    br = null;                }                if (pw != null) {                    pw.close();                    pw = null;                }                if (s != null) {                    s.close();                    s = null;                }            } catch (IOException e) {                System.out.println("IO异常。。。");                e.printStackTrace();            }                    }    } }  -------------------------------------------------------------------------------------------------------------------------------------- 2.最简单的servlet示例说明：①将HelloWorldServlet .class拷贝到test\WEB-INF\classes目录下（test是项目名）②在web.xml中添加对应的servlet处理语句：    <servlet>        <servlet-name>HW</servlet-name>        <servlet-class>HelloWorldServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>HW</servlet-name>        <url-pattern>/abc</url-pattern>    </servlet-mapping>③在URL地址栏中以http://localhost:8888/test/abc形式访问④页面上显示结果：Hello World! import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * 简单的servlet示例 * @author jukey * */public class HelloWorldServlet extends HttpServlet {         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        out.println("Hello World!");    }    } ----------------------------------------------------------------------------------------------------------------------------------- 3.Servlet的生命周期测试 import java.io.IOException; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * Servlet的生命周期 * @author jukey * */public class TestLifeCycleServlet extends HttpServlet {     // 处理请求    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        System.out.println("doGet");    }     // 实例化    // 注意：构造方法不能有返回值类型，连void也不行（否则就变成普通方法了）    public TestLifeCycleServlet() {        System.out.println("constructed");    }        // 退出服务    public void destroy() {        System.out.println("destory");    }     // 初始化    public void init() throws ServletException {        System.out.println("init");    } } /*测试结果（在tomcat服务器控制台窗口）：constructedinitdoGet*/ ------------------------------------------------------------------------------------------------------------------------------------ 4.读取指定的参数 ①Threeparams.htm <form id="form1" name="form1" method="post" action="servlet/Threeparams">    <table width="343" border="1">        <tr>            <td width="92">param1</td>            <td width="94"><input name="param1" type="text" id="param1"/></td>            </tr>        <tr>            <td width="92">param2</td>            <td width="94"><input name="param2" type="text" id="param2"/></td>            </tr>        <tr>            <td width="92">param3</td>            <td width="94"><input name="param3" type="text" id="param3"/></td>            </tr>        <tr>            <td> </td>            <td><input type="submit" value="提交"/></td>            </tr>    </table></form> ②ThreeParams.java import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * 读取指定的参数 * @author jukey * */public class ThreeParams extends HttpServlet {     // 参数在传递过程中，在URL地址栏中显示出来    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setContentType("text/html;charset=gb2312");        PrintWriter pw = response.getWriter();        pw.println(request.getParameter("param1"));        pw.println("<br>");        pw.println(request.getParameter("param2"));        pw.println("<br>");        pw.println(request.getParameter("param3"));        pw.println("<br>");    }     // 参数在传递过程中，在URL地址栏中隐藏了    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        System.out.println("doPost");        // 调用doGet方法        doGet(request,response);    } } ---------------------------------------------------------------------------------------------------------------------------------- 5.读取所有的参数 ①Showparameters.htm <html>    <head>        <title>A sample show parameters</title>    </head>    <body>A sample show parameters            <form method="post" action="servlet/ShowParameters">            Item Number:<input type="text" name="itemNum"><br>            Quantity:<input type="text" name="quantity"><br>            Price each:<input type="text" name="price" value="$"><br>            First Name:<input type="text" name="firstName"><br>            Last Name:<input type="text" name="lastName"><br>            Middle Initial:<input type="text" name="initial"><br>                        Shipping Address:<textarea name="address" row="3" cols="40"></textarea><br>            Credit Card:<br>            <!--单选框示例-->              <input type="radio" name="cardType" value="Visa">Visa<br>              <input type="radio" name="cardType" value="Master Card">Master Card<br>              <input type="radio" name="cardType" value="Amex">Amex<br>              <input type="radio" name="cardType" value="Discover">Discover<br>              <input type="radio" name="cardType" value="Java SmartCard">Java SmartCard<br>            <!--密码输入框-->            Credit Card password:<input type="password" name="cardNum"><br>            Repeat Credit Card password:<input type="password" name="cardNum"><br><br>                        <center><input type="submit" value="Submit Order"></center>                    </form>    </body></html> ②ShowParameters.java 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; /** * 读取所有的参数 * @author jukey * */public class ShowParameters extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();                String title = "Reading All Request Parameters";        out.println("init");        out.println("<html><head><title>读取所有参数</title></head>"                + title                + "\n" + "<table border=1 align=center>\n"                + "<TH>Parameter Name<TH>Parameter Value(s)");                // Returns an Enumeration of String objects containing the names of the parameters contained in this request.         Enumeration paramNames = request.getParameterNames();        // Tests if this enumeration contains more elements.         while(paramNames.hasMoreElements()) {            // Returns the next element of this enumeration if this enumeration object has at least one more element to provide.             String paraName = (String)paramNames.nextElement();            out.println("<tr><td>" + paraName + "\n<td>");            // Returns an array of String objects containing all of the values the given request parameter has, or null if the parameter does not exist.             // 注意参数paraName（变量）不能加双引号，否则就是找参数名叫paraName的对应值了。            String[] paramValues = request.getParameterValues(paraName);            // 这个参数只有一个值            if(paramValues.length == 1) {                String paramValue = paramValues[0];                if(paramValue.length() == 0) {                    out.println("<I>no value</I>");                } else {                    out.println(paramValue);                }            }else {                // 这个参数有好几条值                out.println("<UL>");                for(int i = 0; i < paramValues.length; i++) {                    out.println("<LI>" + paramValues[i]);                }                out.println("</UL>");            }        }        out.println("</table>\n<body></html>");    }     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        System.out.println("doPost");        doGet(request,response);    } } -------------------------------------------------------------------------------------------------------------------------------------------- 6.Cookies的设置和读取 ①设置Cookie到客户端 import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * 设置Cookie到客户端 * @author jukey * */public class SetCookies extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        // 向客户端写入Cookie，共6个        for(int i = 0; i < 3; i++) {            // 3个没有设置时间的Cookie，属于本窗口及其子窗口            Cookie cookie = new Cookie("Session-Cookie-" + i, "Cookie-Value-S" + i);            response.addCookie(cookie);            // 以下3个Cookie设置了时间（3600秒，1小时），属于文本，别的窗口也可以访问到这些Cookie            cookie = new Cookie("Persistent-Cookie-" + i, "Cookie-Value-P" + i);            cookie.setMaxAge(3600);            response.addCookie(cookie);        }                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        String title = "Setting Cookies";        out.println("<html><head><title>设置Cookie</title></head>"                + "<body>" + title + "<br>"                + "There are six cookies associates with this page.<br>"                + "to see them,visit the <a href=\"ShowCookies\">\n"                + "<code>ShowCookies</code> servlet</a>"                + "</body></html>");    } } ②读取客户端的Cookies import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * 读取客户端的Cookies * @author jukey * */public class ShowCookies extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                response.setContentType("text/html;charset=gb2312");        PrintWriter pw = response.getWriter();        String title = "Active Cookies";        pw.println("init");        pw.println("<html><head><title>读取客户端</title></head>"                + title                + "\n" + "<table border=1 align=center>\n"                + "<TH>Cookie Name<TH>Cookie Value" + "<br>");                // 读取客户端的所有Cookie        Cookie[] cookies = request.getCookies();        if(cookies != null) {            Cookie cookie;            for(int i = 0; i < cookies.length; i++) {                cookie = cookies[i];                pw.println("<tr>\n" + "<td>" + cookie.getName() +"</td>\n"                        + "<td>" + cookie.getValue() +"</td></tr>\n");            }        }        pw.println("</table>\n<body><html>");    } } -------------------------------------------------------------------------------------------------------------------------------------- 7.Session的测试 ①演示Servlet API中的session管理机制（常用方法） import java.io.IOException;import java.io.PrintWriter;import java.util.Date; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession; /** * 演示Servlet API中的session管理机制（常用方法） * @author jukey * */public class SessionInfoServlet extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                // Returns the current session associated with this request, or if the request does not have a session, creates one.         HttpSession mySession = request.getSession(true);                response.setContentType("text/html");        PrintWriter out = response.getWriter();        String title = "Session Info Servlet";        out.println("<html>");        out.println("<head>");        out.println("<title>Session Info Servlet</title>");        out.println("</head>");        out.println("<body>");        out.println("<h3>Session Infomation</h3>");                // Returns true if the client does not yet know about the session or if the client chooses not to join the session.         out.println("New Session:" + mySession.isNew() + "<br>");        // Returns a string containing the unique identifier assigned to this session.        out.println("Session Id:" + mySession.getId() + "<br>");        // Returns the time when this session was created, measured in milliseconds since midnight January 1, 1970 GMT.         out.println("Session Create Time:" + new Date(mySession.getCreationTime()) + "<br>");        out.println("Session Last Access Time:" + new Date(mySession.getLastAccessedTime()) + "<br>");                out.println("<h3>Request Infomation</h3>");        // Returns the session ID specified by the client.        out.println("Session Id From Request:" + request.getRequestedSessionId() + "<br>");        // Checks whether the requested session ID came in as a cookie.         out.println("Session Id Via Cookie:" + request.isRequestedSessionIdFromCookie() + "<br>");        // Checks whether the requested session ID came in as part of the request URL.         out.println("Session Id Via URL:" + request.isRequestedSessionIdFromURL() + "<br>");        // Checks whether the requested session ID is still valid.         out.println("Valid Session Id:" + request.isRequestedSessionIdValid() + "<br>");                out.println("<a href=" + response.encodeURL("SessionInfoServlet") + ">refresh</a>");        out.println("</body></html>");        out.close();    } } ②Session追踪 import java.io.IOException;import java.io.PrintWriter;import java.util.Date; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession; /** * Session追踪 * 如果浏览器支持Cookie，创建Session的时候会把SessionId保存在Cookie中 * 否则必须自己编程使用URL重写的方式实现Session：response.encodeURL() * @author jukey * */ public class ShowSession extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        String str = "Session Tracking Example";        String heading;                // 如果会话已经存在，则返回一个HttpSession；否则创建一个新的        HttpSession session = request.getSession(true);        // 从当前session中读取属性accessCount的值        Integer accessCount = (Integer)session.getAttribute("accessCount");        if(accessCount == null) {            accessCount = new Integer(0);            heading = "Welcome newUser";        } else {            heading = "Welcome Back";            accessCount = new Integer(accessCount.intValue() + 1);        }        // 向当前session中插入键（key，属性）值（value）对        // Binds an object to this session, using the name specified.        session.setAttribute("accessCount", accessCount);                out.println("<html><head><title>Session追踪</title></head>"                + "<body>" + heading + "<br>"                + "<h2>Information on Your Session</h2><br>"                + "\n" + "<table border=1 align=center>\n"                + "<TH>Info Type<TH>Value" + "<br>"                + "<tr>\n" + "<td>ID</td>\n"                + "<td>" + session.getId() +"</td></tr>\n"                + "<tr>\n" + "<td>CreatTime</td>\n"                + "<td>" + new Date(session.getCreationTime()) +"</td></tr>\n"                + "<tr>\n" + "<td>LastAccessTime</td>\n"                + "<td>" + new Date(session.getLastAccessedTime()) +"</td></tr>\n"                + "<tr>\n" + "<td>Number of Access</td>\n"                + "<td>" + accessCount +"</td></tr>\n"                + "</body></html>");    } } -------------------------------------------------------------------------------------------------------------------------------- 8.Application测试 import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * Application测试 * 用于保存整个web应用的生命周期内都可以访问的数据 * 可供多个不同窗口访问，可作为某一页面被总共访问次数的计数器（比如网站首页的访问量） * @author jukey * */public class TestServletContext extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();                // Returns a reference to the ServletContext in which this servlet is running.         ServletContext application = this.getServletContext();        // 从当前application中读取属性accessCount的值        Integer accessCount = (Integer)application.getAttribute("accessCount");        if(accessCount == null) {            accessCount = new Integer(0);        } else {            accessCount = new Integer(accessCount.intValue() + 1);        }        // 向当前application中插入键（key，属性）值（value）对        application.setAttribute("accessCount", accessCount);                out.println("<html><head><title>ServletContext测试</title></head><br>"                + "<body><td>" + accessCount +"</td>\n"                + "</body></html>");            } } --------------------------------------------------------------------------------------------------------------------------------------------- 9.Servlet类本身位于包中的情况 package com.bjsxt.servlet; import java.io.IOException;import java.io.PrintWriter; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * Servlet类本身位于包中的情况 * classes中要class文件及其各级目录一起放置 * web中如下设置：<servlet-class>com.bjsxt.servlet.HelloWorldServlet2</servlet-class> * @author jukey * */public class HelloWorldServlet2 extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        out.println("Hello World!");            } } -------------------------------------------------------------------------------------------------------------------------------- 10.在Servlet中直接连接数据库，并查询显示信息 import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * 在Servlet中直接连接数据库，并查询显示信息 * 每个application都应该有自己的驱动包，放在各自项目的WEB-INF\lib\目录下 * @author jukey * */public class ShowRs extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                Connection conn = null;        Statement stmt = null;        ResultSet rs = null;                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        out.println("<table border=1>");        out.println("<tr><td>Content:</td></tr>");         try {            Class.forName("com.mysql.jdbc.Driver");            conn = DriverManager.getConnection("jdbc:mysql://localhost/bbs?user=root&password=mysql");            stmt = conn.createStatement();            String sql = "select * from article";            rs = stmt.executeQuery(sql);            while(rs.next()) {                out.println("<tr>");                out.println("<td>" + rs.getString("cont") + "</td>");                out.println("</tr>");            }        } catch (SQLException ex) {            ex.printStackTrace();        } catch (Exception ex) {            ex.printStackTrace();        } finally {             if (rs != null) {                 try {                     rs.close();                     rs = null;                 } catch (SQLException sqlEx) {                      sqlEx.printStackTrace();                 }             }             if (stmt != null) {                 try {                     stmt.close();                     stmt = null;                 } catch (SQLException sqlEx) {                      sqlEx.printStackTrace();                 }             }             if (conn != null) {                 try {                     conn.close();                     conn = null;                 } catch (SQLException sqlEx) {                      sqlEx.printStackTrace();                 }             }        }    } } ---------------------------------------------------------------------------------------------------------------------------------- 11.Servlet中使用专门的数据库操作类DB ①Servlet中使用专门的数据库操作类DB，这样，本程序就比前一个显得简单清楚 import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement; import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse; /** * Servlet中使用专门的数据库操作类DB，这样，本程序就比前一个显得简单清楚 * DB类，专门跟数据库打交道，分工明确，各司其职 * @author jukey * */public class ShowRsUseBean extends HttpServlet {     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {                response.setContentType("text/html;charset=gb2312");        PrintWriter out = response.getWriter();        out.println("<table border=1>");        out.println("<tr><td>Content:</td></tr>");                // 直接调用DB中的静态方法来为本类服务        Connection conn = DB.getConnection();        Statement stmt = DB.getStatement(conn);        String sql = "select * from article";        ResultSet rs = DB.getResultSet(stmt, sql);                try {            while(rs.next()) {                out.println("<tr>");                out.println("<td>" + rs.getString("cont") + "</td>");                out.println("</tr>");            }        } catch (SQLException e) {            System.out.println("执行SQL遍历过程中出现了错误。。。");            e.printStackTrace();        } finally {            // 直接调用DB中的静态方法来关闭一系列被打开的资源            DB.close(rs);            DB.close(stmt);            DB.close(conn);        }    } } ②专门跟数据库打交道的类 import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement; /** * 专门跟数据库打交道的类 * @author ykn * */public class DB {     // 获取连接    public static Connection getConnection() {        Connection conn = null;        try {            Class.forName("com.mysql.jdbc.Driver");            conn = DriverManager.getConnection("jdbc:mysql://localhost/bbs?user=root&password=mysql");        } catch (ClassNotFoundException e) {            System.out.println("驱动程序未找到，请加入mysql.jdbc的驱动包。。。");            e.printStackTrace();        } catch (SQLException e) {            System.out.println("执行数据库连接过程中出现了错误。。。");            e.printStackTrace();        }        return conn;    }        // 获取表达式语句    public static Statement getStatement(Connection conn) {        Statement stmt = null;        try {            if (conn != null) {                stmt = conn.createStatement();            }        } catch (SQLException e) {            System.out.println("执行获取表达式语句过程中出现了错误。。。");            e.printStackTrace();        }                return stmt;    }        // 获取查询的结果集    public static ResultSet getResultSet(Statement stmt, String sql) {        ResultSet rs = null;        try {            if (stmt != null) {                rs = stmt.executeQuery(sql);            }        } catch (SQLException e) {            System.out.println("执行查询过程中出现了错误。。。");            e.printStackTrace();        }        return rs;    }        // 关闭连接    public static void close(Connection conn) {        try {            if (conn != null) {                conn.close();                conn = null;            }        } catch (SQLException e) {            System.out.println("执行关闭数据库连接过程中出现了错误。。。");            e.printStackTrace();        }            }        // 关闭表达式语句    public static void close(Statement stmt) {        try {            if (stmt != null) {                stmt.close();                stmt = null;            }        } catch (SQLException e) {            System.out.println("执行关闭表达式语句过程中出现了错误。。。");            e.printStackTrace();        }            }        // 关闭结果集    public static void close(ResultSet rs) {        try {            if (rs != null) {                rs.close();                rs = null;            }        } catch (SQLException e) {            System.out.println("执行关闭结果集过程中出现了错误。。。");            e.printStackTrace();        }            }}