Jsp Servlet JavaBean JDBC登陆实例

运行环境：                                                                                         网易博客cyeagle

引用

JDK1.5

Tomcat5.5

MyEclips5.5.1 GA

SqlServer2000

windows2003

1.在SqlServer下的查询分析器中新建表：

create table dbuser(  userId int identity(1,1) primary key not null,  userName varchar(50),  userPasswd varchar(50))  

2.在MyEclipse中新建Web工程，并创建包结构。

3.编写登陆界面。

<%@ page language='java' contentType='text/html; charset=GB18030'      pageEncoding='GB18030'%>    html>  head>  meta http-equiv='Content-Type' content='text/html; charset=GB18030'>  title>Insert title heretitle>  style type='text/css'>  body{   color : #000 ;   font-size : 12px ;     margin : 0px auto ;   }    style>    script type='text/javascript'>      function check(form){      //document.forms.form1.username.value取得form1中Username的值 并判断是否为空          if(document.forms.form1.username.value==''){          //如果 为''则弹出提示              alert('pls input username');              //将输入焦点定位到没有输入的地方              document.forms.form1.username.focus();              //返回错误              return false;          }                  if(document.forms.form1.password.value==''){              alert('pls input password');              document.forms.form1.password.focus();              return false;          }      }    script>  head>  body>  form action='LoginServlet' method='post' name='form1'>              table border='1' cellspacing='1' cellpadding='1'  bordercolor='silver' align='center'>     tr>        td colspan='2' align='center' bgcolor='#e8e8e8'>用户登陆td>     tr>     tr>        td>用户名：td>        td>input type='text' name='username'/>td>     tr>     tr>        td>密码：td>        td>input type='password' name='password'/>td>     tr>     tr>        td>a href='rsg.jsp' >新用户注册a>td>                td>input type='submit' name='submit' onclick='return check(this);'/>input type='reset' name='reset'/>td>     tr>  table>    form>  body>  html>  

3.编写工具类DBConn。

package utils;        import java.io.*;     import java.sql.*;       public class DBConn {             public static String driver;//定义驱动             public static String url;//定义URL             public static String user;//定义用户名             public static String password;//定义密码             public static Connection conn;//定义连接             public static Statement stmt;//定义STMT             public ResultSet rs;//定义结果集             //设置CONN             static{                 try {                   driver='com.microsoft.jdbc.sqlserver.SQLServerDriver';                  url='jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=qtliu';                  user='sa';                  password='sa';                  Class.forName(driver);                     conn = DriverManager.getConnection(url,user,password);                  System.out.println('-------连接成功------');              } catch(ClassNotFoundException classnotfoundexception) {                       classnotfoundexception.printStackTrace();                     System.err.println('db: ' + classnotfoundexception.getMessage());                 } catch(SQLException sqlexception) {                     System.err.println('db.getconn(): ' + sqlexception.getMessage());                 }             }             //构造函数，默认加裁配置文件为jdbc.driver             public DBConn(){                 this.conn=this.getConn();          }             //返回Conn             public Connection getConn(){                 return this.conn;             }             //执行插入                public void doInsert(String sql) {                 try {                     stmt = conn.createStatement();                     int i = stmt.executeUpdate(sql);                 } catch(SQLException sqlexception) {                     System.err.println('db.executeInset:' + sqlexception.getMessage());                 }finally{                                      }             }             //执行删除             public void doDelete(String sql) {                 try {                     stmt = conn.createStatement();                     int i = stmt.executeUpdate(sql);                 } catch(SQLException sqlexception) {                     System.err.println('db.executeDelete:' + sqlexception.getMessage());                 }             }             //执行更新             public void doUpdate(String sql) {                 try {                     stmt = conn.createStatement();                     int i = stmt.executeUpdate(sql);                 } catch(SQLException sqlexception) {                     System.err.println('db.executeUpdate:' + sqlexception.getMessage());                 }             }             //查询结果集             public ResultSet doSelect(String sql) {                 try {                  conn=DriverManager.getConnection(url,user,password);                  stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);                       rs = stmt.executeQuery(sql);                   System.out.println('取得结果集');              } catch(SQLException sqlexception) {                     System.err.println('db.executeQuery: ' + sqlexception.getMessage());                 }                 return rs;             }             /**            *关闭数据库结果集，数据库操作对象，数据库链接              @Function: Close all the statement and conn int this instance and close the parameter ResultSet              @Param: ResultSet              @Exception: SQLException,Exception             **/             public void close(ResultSet rs) throws SQLException, Exception {                        if (rs != null) {                  rs.close();                  rs = null;                }                        if (stmt != null) {                  stmt.close();                  stmt = null;                }                        if (conn != null) {                  conn.close();                  conn = null;                }              }                      /**             *关闭数据库操作对象，数据库连接对象             * Close all the statement and conn int this instance             * @throws SQLException             * @throws Exception             */             public void close() throws SQLException, Exception {                if (stmt != null) {                  stmt.close();                  stmt = null;                }                        if (conn != null) {                  conn.close();                  conn = null;                }              }             //测试类     //       public static void main(String []args){  //           DBConn db=new DBConn();  //           db.getConn();  //          ResultSet rs=db.doSelect('select * from db_user where userName='admin'');  //          try {  //              while(rs.next()){  //                  System.out.println(rs.getInt(1));  //                  System.out.println(rs.getString(3));  //                    //              }  //          } catch (SQLException e) {  //              // TODO Auto-generated catch block  //              e.printStackTrace();  //          }  //       }      }    

4.编写Servlet,LoginServlet.java。

package servlet;    import java.io.IOException;    import javax.servlet.RequestDispatcher;  import javax.servlet.ServletException;  import javax.servlet.http.HttpServlet;  import javax.servlet.http.HttpServletRequest;  import javax.servlet.http.HttpServletResponse;    import model.CheckUser;  import beans.UserBean;    public class LoginServlet extends HttpServlet {        /**      *       */      private static final long serialVersionUID = 7381169134016556647L;        public void doGet(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {              doPost(request,response);      }        public void doPost(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {          //设置HTTP响应的文档类型,此处为Text/html,如果更改为application\msword则设置为word文档格式          response.setContentType('text/html');          //设置响应所采用的编码方式          response.setCharacterEncoding('GB18030');          //取得参数username的值          String uname=request.getParameter('username');          String passwd=request.getParameter('password');                              UserBean user=new UserBean();          user.setUsername(uname);          user.setPassword(passwd);          CheckUser cku=new CheckUser();          boolean bool=cku.checkUsre(user);                    String forward;          if(bool){              forward='success.jsp';                        }else{              forward='error.jsp';          }          RequestDispatcher rd=request.getRequestDispatcher(forward);          rd.forward(request,response);      }      }  

5.在web.xml中配置Servlet。

引用

配置关键代码

servlet>     servlet-name>LoginServletservlet-name>     servlet-class>servlet.LoginServletservlet-class>   servlet>     servlet-mapping>     servlet-name>LoginServletservlet-name>     url-pattern>/LoginServleturl-pattern>   servlet-mapping>  

本机上的整个Web.xml代码

  web-app version='2.5'       xmlns='http://java./xml/ns/javaee'       xmlns:xsi='http://www./2001/XMLSchema-instance'       xsi:schemaLocation='http://java./xml/ns/javaee       http://java./xml/ns/javaee/web-app_2_5.xsd'>    servlet>      servlet-name>LoginServletservlet-name>      servlet-class>servlet.LoginServletservlet-class>    servlet>      servlet-mapping>      servlet-name>LoginServletservlet-name>      url-pattern>/LoginServleturl-pattern>    servlet-mapping>    welcome-file-list>      welcome-file>index.jspwelcome-file>    welcome-file-list>  web-app>  

5.编写userBean。

package beans;    public class UserBean {              public String username;      public String password;            public UserBean() {          super();      }                  public String getPassword() {          return password;      }      public void setPassword(String password) {          this.password = password;      }      public String getUsername() {          return username;      }      public void setUsername(String username) {          this.username = username;      }    }  

6.编写JavaBean CheckUser。

package model;    import java.sql.ResultSet;  import java.sql.SQLException;    import utils.DBConn;  import utils.DBUtils;  import beans.UserBean;    public class CheckUser {            public boolean checkUsre(UserBean user){          if(user.username.equals('')||user.username!=null){              ResultSet rs=null;              DBConn db=new DBConn();              rs=db.doSelect('select * from db_user where userName=''+user.getUsername()+''');              try {                  if(rs.next()){                      if(user.password.equals('')||user.password!=null){                          rs=db.doSelect('select * from db_user where userPasswd='+user.password);                          return true;                      }                  }              } catch (SQLException e) {                  e.printStackTrace();              }          }                    return false;                }    }  

7.编写错误页面及成功登陆页面。

error.jsp

<%@ page language='java' contentType='text/html; charset=GB18030'      pageEncoding='GB18030'%>    html>  head>  meta http-equiv='Content-Type' content='text/html; charset=GB18030'>  title>Insert title heretitle>  head>  body>  Sorry!你的登陆信息不正确!系统无法让你登陆!a href='login.jsp'>点击返回a>  body>  html>  

success.jsp

<%@ page language='java' contentType='text/html; charset=GB18030'      pageEncoding='GB18030'%>    jsp:useBean id='user' class='beans.UserBean' scope='request'/>  jsp:setProperty name='user' property='*'/>    html>  head>  meta http-equiv='Content-Type' content='text/html; charset=GB18030'>  title>Insert title heretitle>  head>  body>  <%       session.setAttribute('user',user);      String username=user.getUsername();   %>      <%=username %>,欢迎您来到FUCK网!br>   您的IP是:<%=request.getRemoteAddr() %>br>  你的主机是:<%=request.getRemoteHost() %>br>  你使用的协议是:<%=request.getProtocol() %>br>  你目前的地址是:<%=request.getRealPath('/') %>  你的主机端口是:<%=request.getRemotePort() %>  body>  html>  

=====================================================================

页面流向图

所涉知识点：

*JDBC连接的数据库的写法

*在JSP中使用JavaBean

与

与是联系在一起的，在中的name值应当和中的ID值相同。

jsp:useBean id='user' class='beans.UserBean' scope='request'/>  jsp:setProperty name='user' property='*'/>  

*js验证的写法，及在页面中的触发

script type='text/javascript'>      function check(form){          if(document.forms.form1.username.value==''){              alert('pls input username');              document.forms.form1.username.focus();              return false;          }                  if(document.forms.form1.password.value==''){              alert('pls input password');              document.forms.form1.password.focus();              return false;          }      }    script>    input type='submit' name='submit' onclick='return check(this);'/>  

*request、response的常见用法

request常用方法    取得相关信息：  您的IP是:<%=request.getRemoteAddr() %>br>  你的主机是:<%=request.getRemoteHost() %>br>  你使用的协议是:<%=request.getProtocol() %>br>  你目前的地址是:<%=request.getRealPath('/') %>    接收请求内容：    通过：Request.getParemeter(“username”) 接收请求内容：代码如下所示：  String name = request.getParameter('uname') ;  取得文本框提交的信息  String name = request.getParameter('uname') ;  取得按钮的名字：  String name = request.getParameter('submit') ;    设置浏览器的输出文件类型，及编码标准  <%@page contentType='text/html;charset=gb2312'%>    两秒后自动跳转到新页面：  <%response.setHeader('refresh','3;URL=login.jsp');%>    //设置HTTP响应的文档类型,此处为Text/html,如果更改为application\msword则设置为word文档格式    response.setContentType('text/html');    //设置响应所采用的编码方式  response.setCharacterEncoding('GB18030');  

*转发和重定向的区别

转向页面：

重定向（redirect）：以前的request中存放的变量全部失效，并进入一个新的request作用域。

转发（Forward）：以前的request中存放的变量不会失效，就像把两个页面拼到了一起。

（注：只要使用了服务器端跳转,则请求内容可以在跳转之后的页面继续得到）

Java代码  

Response.sendRedirect(“URL”);//重定向    request.getRequestDispatcher('apage.jsp').forward(request, response);//转发到apage.jsp  <>'d.jsp'/>   //转发到d.jsp 在JSP中使用  response.sendRedirect('apage.jsp');//重定向到apage.jsp

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