基于Servlet实现技术问答网站系统

@WebServlet( "/list.do" ) 
public class ListServlet extends HttpServlet { 
 private static final long serialVersionUID = 810339694607399128L; 
 @Override 
 protected void service( HttpServletRequest request , HttpServletResponse response ) 
   throws ServletException, IOException { 
 String question=request.getParameter("quest"); 
 System.out.println(question); 
 if(StringHelper.notEmpty(question)){ 
  final String SQL = "SELECT id , title ,content, publish_time , publish_ip , user_id FROM t_topic where title =? " ; 
  ResultSet rs = JdbcHelper.query( SQL,question ); 
   // 创建一个 List 对象，用来保存一批 Topic 对象 
  final List<Topic> topics = new ArrayList<>(); 
  try { 
   // 每循环一次，光标下移一行，如果该行有数据返回 true 
   while( rs.next() ){ 
    Topic t = new Topic(); // 创建对象 
    t.setId( rs.getInt( 1 ) ); // 将 结果集 中的 该行数据 封装到 t 对象的 id 属性中 
    t.setTitle( rs.getString( 2 ) ); 
    t.setContent(rs.getString(3)); 
    t.setPublishTime( rs.getTimestamp( 4 )); 
    t.setPublishIp( rs.getString( 5 ) ); 
    User u = new User(); // 创建 一个 User 对象 
    u.setId( rs.getInt( 6 ) ); // 将 t_topic 表中的 user_id 放入到 User 对象的 id 属性中 
    t.setUser( u ); // 将 User 对象 设置到 Topic 对象上 
    /** 将 本次循环 创建的对象(已经封装数据) 添加到 List 集合中 */ 
    topics.add( t ); 
    } 
   } catch (SQLException e) { 
    e.printStackTrace(); 
   } 
   JdbcHelper.release( rs ); // 关闭 结果集，释放相关的资源 
   /**** 为每个问题寻找提问者 ***********************************/ 
   //for( int i = 0 ; i < topics.size() ; i++ ){ 
   for( int i = 0 , len = topics.size() ; i < len ; i++ ){ 
    Topic t = topics.get( i ) ; // 获得 题目 
    User u = t.getUser(); // 获得当前题目的User对象 ( 该对象中只有 id 没有其它数据 ) 
    // 根据 用户对象的 id 来查询 用户的信息 
    String querySQL = "SELECT id , username , password FROM t_user WHERE id = ? " ; 
    ResultSet userRs = JdbcHelper.query( querySQL , u.getId() ); 
    try { 
     if( userRs.next() ) { // 如果查询到用户信息 
      // 注意，这里应该使用 userRs 
      u.setUsername( userRs.getString( 2 ) ); // 将 username 列的值设置到 用户对象的 username 属性中 
      u.setPassword( userRs.getString( 3 )); // 将 password 列的值设置到 用户对象的 password 属性中 
     } 
    } catch (SQLException e) { 
     e.printStackTrace(); 
    } 
    JdbcHelper.release( userRs ); // 关闭 结果集，释放相关的资源 
   } 
   ServletContext application = request.getServletContext(); 
   /** 将这些数据保存到 application **/ 
   application.setAttribute( "topics" , topics ); 
   System.out.println( "问题列表: " + topics ); 
   // 去 list.html 页面 
   response.sendRedirect( request.getContextPath() + "/list.html"); 
  }else{ 
   /**** 查询数据库中的所有问题 ***********************************/ 
   final String SQL = "SELECT id , title ,content ,publish_time , publish_ip , user_id FROM t_topic ORDER BY publish_time DESC" ; 
   ResultSet rs = JdbcHelper.query( SQL ); 
   // 创建一个 List 对象，用来保存一批 Topic 对象 
   final List<Topic> topics = new ArrayList<>(); 
   try { 
    // 每循环一次，光标下移一行，如果该行有数据返回 true 
    while( rs.next() ){ 
     Topic t = new Topic(); // 创建对象 
     t.setId( rs.getInt( 1 ) ); // 将 结果集 中的 该行数据 封装到 t 对象的 id 属性中 
     t.setTitle( rs.getString( 2 ) ); 
     t.setContent(rs.getString(3)); 
     t.setPublishTime( rs.getTimestamp( 4 )); 
     t.setPublishIp( rs.getString( 5 ) ); 
     User u = new User(); // 创建 一个 User 对象 
     u.setId( rs.getInt( 6) ); // 将 t_topic 表中的 user_id 放入到 User 对象的 id 属性中 
     t.setUser( u ); // 将 User 对象 设置到 Topic 对象上 
     /** 将 本次循环 创建的对象(已经封装数据) 添加到 List 集合中 */ 
     topics.add( t ); 
    } 
   } catch (SQLException e) { 
    e.printStackTrace(); 
   } 
   JdbcHelper.release( rs ); // 关闭 结果集，释放相关的资源 
   /**** 为每个问题寻找提问者 ***********************************/ 
   //for( int i = 0 ; i < topics.size() ; i++ ){ 
   for( int i = 0 , len = topics.size() ; i < len ; i++ ){ 
    Topic t = topics.get( i ) ; // 获得 题目 
    User u = t.getUser(); // 获得当前题目的User对象 ( 该对象中只有 id 没有其它数据 ) 
    // 根据 用户对象的 id 来查询 用户的信息 
    String querySQL = "SELECT id , username , password FROM t_user WHERE id = ? " ; 
    ResultSet userRs = JdbcHelper.query( querySQL , u.getId() ); 
    try { 
     if( userRs.next() ) { // 如果查询到用户信息 
      // 注意，这里应该使用 userRs 
      u.setUsername( userRs.getString( 2 ) ); // 将 username 列的值设置到 用户对象的 username 属性中 
      u.setPassword( userRs.getString( 3 )); // 将 password 列的值设置到 用户对象的 password 属性中 
     } 
    } catch (SQLException e) { 
     e.printStackTrace(); 
    } 
    JdbcHelper.release( userRs ); // 关闭 结果集，释放相关的资源 
   } 
   ServletContext application = request.getServletContext(); 
   /** 将这些数据保存到 application **/ 
   application.setAttribute( "topics" , topics ); 
   System.out.println( "问题列表: " + topics ); 
   // 去 list.html 页面 
   response.sendRedirect( request.getContextPath() + "/list.html"); 
 } 
 } 
} 

<!DOCTYPE html> 
<html> 
 <head> 
  <meta charset="UTF-8"> 
  <title>首页</title> 
  <link rel="stylesheet" href="$path/styles/general.css"> 
  <link rel="stylesheet" href="$path/styles/cell.css"> 
  <link rel="stylesheet" href="$path/styles/wen.css"> 
 </head> 
 <body> 
  
  ## 登录状态栏 开始 
  <div class="login-status-container auto-height"> 
    <span class="welcome cell-8"> 
     ## 在 $ 之后 表达式之前使用 ! 表示 安静模式 ( 静默模式 ) 
     <b>欢迎$!user.username来到爱问社区</b> 
    </span> 
    <span class="login-operation cell-4"> 
     #if( $user ) 
      <a href="$path/ask.html">提问</a> 
      <em>|</em> 
      <a href="$path/myQuestion.do">我的提问</a> 
      <em>|</em> 
      <a href="$path/logout.do">注销</a> 
     #else 
      <a href="$path/login.html">登录</a> 
      <em>|</em> 
      <a href="$path/regist.html">注册</a> 
     #end 
    </span> 
  </div> ## 登录状态栏 结束 
   
  ## 标志区域 
  <div class="brand-container auto-height"> 
   <div class="cell-2"> 
    <a href="$path"></a> 
   </div> 
   <div class="slogan cell-10"> 
    <div> 
    爱问社区，这里可放logo 
    </div> 
   </div> 
  </div> 
   
  ## 列表区域 
  <div class="topic-list-container clear"> 
   <!-- 问题列表的标题 --> 
   <div class="topic-list-header row clear"> 
    <span class="topic-item-index cell-1">序号</span> 
    <span class="topic-item-title cell-5" >标题</span> 
    <span class="topic-item-time cell-3">提问时间</span> 
    <span class="topic-item-user cell-2">提问者</span> 
    <span class="topic-item-operation cell-1"> 
     #if( $user ) 
      解答问题 
     #end 
    </span> 
   </div> 
 
    ## 问题列表开始 
     ## 每循环一次从 $topics 集合中取出一个 Topic 对象 放到 $topic 中 
     #foreach( $topic in $topics ) 
    
     <div class="topic-item row clear odd"> 
       <span class="topic-item-index cell-1">$topic.id</span> 
       <span class="topic-item-title cell-5" > 
        <a href="$path/detail.do?id=$topic.id">$topic.title</a> 
       </span> 
       <span class="topic-item-time cell-3"> $topic.publishTime </span> 
       <span class="topic-item-user cell-2"> $topic.user.username</span> 
       <span class="topic-item-operation cell-1"> 
        #if( $user ) 
         <a href="$path/answer.do?id=$topic.id">解答</a> 
        #end 
       </span> 
     </div> 
      
   
    #end 
   ## 问题列表结束 
    
  </div>## 列表区域结束 
   
  <div class="line"></div> 
   
  <div class="container link-container"> 
   <a href="$path/ask.html" >发起新问题</a> 
   | 
   <a href="$path/index.html" >返回首页</a> 
  </div> 
   
  <div class="container copyright-container"> 
   &copy; 2017 爱问社区版权所有 
  </div> 
  
 </body> 
</html> 

<!DOCTYPE html> 
 
<html> 
 <head> 
  <meta charset="UTF-8"> 
  <title>提问</title> 
  <link rel="stylesheet" href="$path/styles/general.css"> 
  <link rel="stylesheet" href="$path/styles/cell.css"> 
  <link rel="stylesheet" href="$path/styles/wen.css"> 
  <link rel="stylesheet" href="$path/styles/btn.css"> 
   
  <!-- 链接 simditor 的样式库 --> 
  <link rel="stylesheet" href="$path/simditor/styles/simditor.css" type="text/css"> 
  <!-- 导入 simditor 的 JavaScript 库 --> 
  <script type="text/javascript" src="$path/simditor/scripts/jquery.min.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/module.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/hotkeys.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/uploader.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/simditor.min.js"></script> 
   
 </head> 
 <body> 
  
  ## 登录状态栏 开始 
  <div class="id="topnav" class="f_r"> 
    <span class="welcome cell-8"> 
     ## 在 $ 之后 表达式之前使用 ! 表示 安静模式 ( 静默模式 ) 
     <b>欢迎$!user.username来到爱问社区</b> 
    </span> 
    <span class="login-operation cell-4"> 
     #if( $user ) 
      <a href="$path/ask.html">提问</a> 
      <em>|</em> 
      <a href="$path/myQuestion.do">我的提问</a> 
      <em>|</em> 
      <a href="$path/logout.do">注销</a> 
     #else 
      <a href="$path/login.html">登录</a> 
      <em>|</em> 
      <a href="$path/regist.html">注册</a> 
     #end 
    </span> 
  </div> ## 登录状态栏 结束 
   
  <div class="brand-container auto-height"> 
   <div class="cell-2"> 
    <a href="$path"></a> 
   </div> 
   <div class="slogan cell-10"> 
    <div> 
    爱问社区，这里可以logo 
    </div> 
   </div> 
  </div> 
   
  <div class="container message-container"> 
   <!-- 显示提示信息的地方 --> 
   #if( $askFail ) 
    $askFail 
    $scope.remove( $session , 'askFail' ) 
   #end 
  </div> 
   
  #if( $user ) 
  <!-- 提问表单 提交给 ask.do 对应的 Servlet 处理 --> 
  <form action="$path/ask.do" method="post" > 
  <!-- 提问区域 开始 --> 
  <div class="container topic-ask-container clear shadow-outside auto-height" > 
   <!-- 问题的标题 和 提问按钮 --> 
   <div class="container title-container"> 
    <div class="cell-11"> 
     <input type="text" name="title" placeholder="请输入你要提问的问题的标题" class="u-ipt"> 
    </div> 
    <div class="cell-1"> 
     <input type="submit" value="提问" class="u-btn u-btn-c4"> 
    </div> 
   </div> 
    
   <div class="line"></div> 
    
   <!-- 问题的内容 --> 
   <div> 
    <textarea name="content" id="contentEditor" ></textarea> 
    <script type="text/javascript" > 
     var editor = new Simditor( { 
      textarea : $('#contentEditor'), 
      placeholder : '请在这里输入问题的内容...', 
      toolbar : true 
     } ); 
    </script> 
   </div> 
    
   <div class="line"></div> 
    
   <!-- 最底部的提问按钮 --> 
   <div class="container title-container"> 
    <div class="cell-11" ></div> 
    <div class="cell-1"> 
     <input type="submit" value="提问" class="u-btn u-btn-c4"> 
    </div> 
   </div> 
  </div> <!-- 提问区域 结束 --> 
  </form> 
  #else 
   <div > 
    登录以后才能发起提问，请<a href="$path/login.html" >登录</a> 
   </div> 
  #end 
   
  <div class="line"></div> 
   
  <div class="container link-container"> 
   <a href="$path/list.do" >问题列表</a> 
   | 
   <a href="$path/index.html" >返回首页</a> 
  </div> 
   
  <div class="container copyright-container"> 
   &copy; 2017 爱问社区版权所有 
  </div> 
   
 </body> 
</html> 

@WebServlet("/answer.do") 
public class AnswerServlet extends HttpServlet { 
 
 private static final long serialVersionUID = 8578962149437664830L; 
 
 @Override 
 protected void service(HttpServletRequest request, HttpServletResponse response) 
   throws ServletException, IOException { 
 
  // 从 请求中获得请求参数的值 
  String id = request.getParameter("id"); 
 
  if (StringHelper.notEmpty(id)) { 
 
   try { 
    int topicId = Integer.parseInt(id); // 将字符串按照 十进制 解析问 int 类型数值 
 
    // 根据得到的 问题的 主键 查询数据库，得到 详细信息 
    final String SQL = "SELECT id , title , content , publish_time , publish_ip , user_id FROM t_topic WHERE id = ? "; 
 
    ResultSet rs = JdbcHelper.query(SQL, topicId); 
 
    Topic t = null; 
    int userId = -1; 
 
    if (rs.next()) { // 当 根据 问题的主键 获取到 问题信息时 
     t = new Topic(); // 创建 Topic 对象 
 
     t.setId(rs.getInt(1)); // 将 结果集 中的 该行数据 封装到 t 对象的 id 属性中 
     t.setTitle(rs.getString(2)); 
     t.setContent(rs.getString(3)); 
     t.setPublishTime(rs.getTimestamp(4)); 
     t.setPublishIp(rs.getString(5)); 
 
     userId = rs.getInt(6); 
    } 
 
    JdbcHelper.release(rs); // 关闭结果集 
 
    // 获得提问者 
    final String getUserSQL = "SELECT id , username , password FROM t_user WHERE id = ? "; 
    rs = JdbcHelper.query(getUserSQL, userId); 
    if (userId != -1 && rs.next()) { 
     User u = new User(); 
     // 封装数据 
     u.setId(rs.getInt(1)); 
     u.setUsername(rs.getString(2)); 
     u.setPassword(rs.getString(3)); 
     // 将获取到的用户数据设置到 Topic 对象的 user 属性中 
     t.setUser(u); 
    } 
 
    HttpSession session = request.getSession(); 
    session.setAttribute("topic", t); 
 
    response.sendRedirect(request.getContextPath() + "/answer.html"); 
 
    return; // 让方法立即结束 
   } catch (NumberFormatException e) { 
    e.printStackTrace(); 
    // response.sendRedirect( request.getContextPath() + "/list.do" ); 
   } catch (SQLException e) { 
    e.printStackTrace(); 
    // response.sendRedirect( request.getContextPath() + "/list.do" ); 
   } 
 
  } else { 
   // response.sendRedirect( request.getContextPath() + "/list.do" ); 
  } 
 
  response.sendRedirect(request.getContextPath() + "/list.do"); 
 
 } 
 
} 

<!DOCTYPE html> 
<html> 
 <head> 
  <meta charset="UTF-8"> 
  <title>解答: $topic.title</title> 
  <link rel="stylesheet" href="$path/styles/general.css"> 
  <link rel="stylesheet" href="$path/styles/cell.css"> 
  <link rel="stylesheet" href="$path/styles/wen.css"> 
   
  <!-- 链接 simditor 的样式库 --> 
  <link rel="stylesheet" href="$path/simditor/styles/simditor.css" type="text/css"> 
  <!-- 导入 simditor 的 JavaScript 库 --> 
  <script type="text/javascript" src="$path/simditor/scripts/jquery.min.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/module.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/hotkeys.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/uploader.js"></script> 
  <script type="text/javascript" src="$path/simditor/scripts/simditor.min.js"></script> 
   
 </head> 
 <body> 
  
  ## 登录状态栏 开始 
  <div class="login-status-container auto-height"> 
    <span class="welcome cell-8"> 
     ## 在 $ 之后 表达式之前使用 ! 表示 安静模式 ( 静默模式 ) 
     <b>欢迎$!user.username来到爱问社区</b> 
    </span> 
    <span class="login-operation cell-4"> 
     #if( $user ) 
      <a href="$path/ask.html">提问</a> 
      <em>|</em> 
      <a href="">我的提问</a> 
      <em>|</em> 
      <a href="$path/logout.do">注销</a> 
     #else 
      <a href="$path/login.html">登录</a> 
      <em>|</em> 
      <a href="$path/regist.html">注册</a> 
     #end 
    </span> 
  </div> ## 登录状态栏 结束 
   
  ## 标志区域 
  <div class="brand-container auto-height"> 
   <div class="logo cell-2"> 
    <a href="$path"></a> 
   </div> 
   <div class="slogan cell-10"> 
    <div> 
    解答问题 
    </div> 
   </div> 
  </div> 
   
   <div> 
    <h4>$topic.title</h4> 
    <div class="line"></div> 
    <div> 
     $topic.content 
    </div> 
    <div> 
     提问时间: $topic.publishTime / 提问者: $topic.user.username 
    </div> 
   </div> 
    
   <!-- 解答的内容 --> 
   <form action="$path/explain.do" method="post" > 
    <input type="hidden" name="id" value="$topic.id" > 
   <div> 
    <textarea name="content" id="contentEditor" ></textarea> 
    <script type="text/javascript" > 
     var editor = new Simditor( { 
      textarea : $('#contentEditor'), 
      placeholder : '请在这里输入问题的内容...', 
      toolbar : true 
     } ); 
    </script> 
   </div> 
   <input type="submit" value="提交解答"> 
   </form> 
   
   
   
  $scope.remove( $session , 'topic' ); 
   
  <div class="line"></div> 
   
  <div class="container link-container"> 
   <a href="$path/ask.html" >发起新问题</a> 
   | 
   <a href="$path/index.html" >返回首页</a> 
  </div> 
   
  <div class="container copyright-container"> 
   &copy; 2017 爱问社区版权所有 
  </div> 
  
 </body> 
</html> 

<textarea name="content" id="contentEditor" ></textarea> 
<script type="text/javascript" > 
     var editor = new Simditor( { 
      textarea : $('#contentEditor'), 
      placeholder : '请在这里输入问题的内容...', 
      toolbar : true 
     } ); 
</script> 

@WebServlet("/detail.do") 
public class DetailServlet extends HttpServlet { 
 private static final long serialVersionUID = -3202278077673657729L; 
 @Override 
 protected void service(HttpServletRequest request, HttpServletResponse response) 
  throws ServletException, IOException { 
 // 从 请求中获得请求参数的值 
 String id = request.getParameter("id"); 
 if (StringHelper.notEmpty(id)) { 
  try { 
  int topicId = Integer.parseInt(id); // 将字符串按照 十进制 解析问 int 类型数值 
  // 根据得到的 问题的 主键 查询数据库，得到 详细信息 
  final String SQL = "SELECT id , title , content , publish_time , publish_ip , user_id FROM t_topic WHERE id = ? "; 
  ResultSet rs = JdbcHelper.query(SQL, topicId); 
  Topic t = null; 
  /*int userId = -1;*/ 
  if (rs.next()) { // 当 根据 问题的主键 获取到 问题信息时 
   t = new Topic(); // 创建 Topic 对象 
   t.setId(rs.getInt(1)); // 将 结果集 中的 该行数据 封装到 t 对象的 id 属性中 
   t.setTitle(rs.getString(2)); 
   t.setContent(rs.getString(3)); 
   t.setPublishTime(rs.getTimestamp(4)); 
   t.setPublishIp(rs.getString(5)); 
   User user = new User(); 
   user.setId(rs.getInt(6)); 
   t.setUser(user); 
  } 
  JdbcHelper.release(rs); // 关闭结果集 
  // 获得提问者 
  final String getUserSQL = "SELECT id , username , password FROM t_user WHERE id = ? "; 
  rs = JdbcHelper.query(getUserSQL, t.getUser().getId()); 
  if(rs.next()) 
  { 
   User u = new User(); 
   // 封装数据 
   u.setId(rs.getInt(1)); 
   u.setUsername(rs.getString(2)); 
   u.setPassword(rs.getString(3)); 
   // 将获取到的用户数据设置到 Topic 对象的 user 属性中 
   t.setUser(u); 
   System.out.println("message username:" + rs.getString(2)); 
  } 
  JdbcHelper.release(rs); // 关闭结果集 
  // 获得当前的问题的所有解答 
  String explainSQL = "SELECT id , content , explain_time , explain_ip , user_id from t_explain where topic_id = ? "; 
  rs = JdbcHelper.query(explainSQL, topicId); 
  @SuppressWarnings("unused") 
  int explainerId = -1; 
  List<Explain> explains = new ArrayList<>(); 
  while (rs.next()) { 
   Explain e = new Explain(); 
   e.setId(rs.getInt(1)); 
   e.setContent(rs.getString(2)); 
   e.setExplainTime(rs.getTimestamp(3)); 
   e.setExplainIp(rs.getString(4)); 
   User user=new User(); 
   user.setId(rs.getInt(5)); 
   e.setUser(user); 
   explains.add(e); 
   System.out.println("explain userID:" + rs.getInt(5)); 
  } 
  // 获得解答者 
  List<Explain>explainList = new ArrayList(); 
  for(int i=0;i<explains.size();i++) 
  { 
   Explain explain1 = explains.get(i); 
   final String getExplainerSQL = "SELECT id , username , password FROM t_user WHERE id = ? "; 
    
   rs = JdbcHelper.query(getExplainerSQL, explain1.getUser().getId()); 
   if (rs.next()) { 
    User u = new User(); 
    // 封装数据 
    u.setId(rs.getInt(1)); 
    u.setUsername(rs.getString(2)); 
    u.setPassword(rs.getString(3)); 
    // 将获取到的用户数据设置到 Topic 对象的 user 属性中 
    explain1.setUser(u); 
    explainList.add(explain1); 
    System.out.println("explain username:" + rs.getString(2)); 
   } 
   JdbcHelper.release(rs); // 关闭结果集 
   /*t.setExplains(explains); // 将解答设置到 Topic 对象上 
*/  } 
  t.setExplains(explainList); 
   
  /*** 为 所有的解答，获取解答者的详细信息 ***/ 
  HttpSession session = request.getSession(); 
  session.setAttribute("topic", t); 
  response.sendRedirect( request.getContextPath() + "/detail.html" ); 
  return; // 让方法立即结束 
  } catch (NumberFormatException e) { 
  e.printStackTrace(); 
 
  } catch (SQLException e) { 
  e.printStackTrace(); 
 
  } 
 } else { 
 } 
 response.sendRedirect(request.getContextPath() + "/list.do"); 
 
 } 
 
} 

<!DOCTYPE html> 
 
<html> 
 <head> 
  <meta charset="UTF-8"> 
  <title>$topic.title</title> 
  <link rel="shortcut icon" href="$path/images/icon.png" type="image/png"> 
  <link rel="stylesheet" href="$path/styles/general.css"> 
  <link rel="stylesheet" href="$path/styles/cell.css"> 
  <link rel="stylesheet" href="$path/styles/wen.css"> 
 </head> 
 <body> 
  
  ## 登录状态栏 开始 
  <div class="login-status-container auto-height"> 
    <span class="welcome cell-8"> 
     ## 在 $ 之后 表达式之前使用 ! 表示 安静模式 ( 静默模式 ) 
     <b>欢迎$!user.username来到问道</b> 
    </span> 
    <span class="login-operation cell-4"> 
     #if( $user ) 
      <a href="$path/ask.html">提问</a> 
      <em>|</em> 
      <a href="">我的提问</a> 
      <em>|</em> 
      <a href="$path/logout.do">注销</a> 
     #else 
      <a href="$path/login.html">登录</a> 
      <em>|</em> 
      <a href="$path/regist.html">注册</a> 
     #end 
    </span> 
  </div> ## 登录状态栏 结束 
   
  ## 标志区域 
  <div class="brand-container auto-height"> 
   <div class="logo cell-2"> 
    <a href="$path"></a> 
   </div> 
   <div class="slogan cell-10"> 
    <div> 
    </div> 
   </div> 
  </div> 
   
  <div> 
   <h4>$topic.title</h4> 
   <div class="line"></div> 
   <div> 
    $topic.content 
   </div> 
   <div> 
    提问时间: $topic.publishTime / 提问者: $topic.user.username 
   </div> 
  </div> 
   
  <div> 
   #foreach( $ex in $topic.explains) 
    <div> $ex.content </div> 
    <div class="line"></div> 
   #end 
  </div> 
   
  $scope.remove( $session , 'topic' ); 
   
  <div class="line"></div> 
   
  <div class="container link-container"> 
   <a href="$path/ask.html" >发起新问题</a> 
   | 
   <a href="$path/index.html" >返回首页</a> 
  </div> 
   
  <div class="container copyright-container"> 
   &copy; 2017 爱问社区版权所有 
  </div> 
  
 </body> 
</html> 

@WebServlet("/myAnswer.do") 
public class MyAnswerServlet extends HttpServlet { 
 
 private static final long serialVersionUID = -3020889403557912216L; 
 
 @Override 
 protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
  HttpSession session = request.getSession(); 
  User user = (User) session.getAttribute( "user" ); // 在登录时将 User 对象放入了 会话 中 
  Explain ex=null; 
  final List<Explain> exp = new ArrayList<>(); 
  if( user != null ) { 
  int myid=user.getId(); 
  final String SQL = "SELECT id ,content ,explain_time , explain_ip , user_id ,topic_id FROM t_explain WHERE user_id = ? "; 
  ResultSet rs = JdbcHelper.query(SQL, myid); 
  //Topic t=null; 
  //final List<Explain> explains = new ArrayList<>(); 
  @SuppressWarnings("unused") 
  int topicId=-1; 
  try { 
   while( rs.next() ) 
   { 
   ex=new Explain(); 
   ex.setId(rs.getInt(1)); 
   ex.setContent(rs.getString(2)); 
   ex.setExplainTime(rs.getTimestamp( 3 )); 
   ex.setExplainIp(rs.getString(4)); 
   ex.setUser(user); 
   Topic to=new Topic(); 
   to.setId(rs.getInt(6)); 
   ex.setTopic(to); 
   topicId=rs.getInt(6); 
   exp.add(ex); 
    
   } 
   JdbcHelper.release(rs); // 关闭结果集 
    
   for(int i = 0 , len = exp.size() ; i < len ; i++) 
   { 
   Explain explain=exp.get(i); 
   Topic tid=explain.getTopic(); 
   final String tSQL = "SELECT id , title , content , publish_time , publish_ip , user_id FROM t_topic WHERE id = ? "; 
   ResultSet trs = JdbcHelper.query(tSQL, tid.getId()); 
   while(trs.next()) 
   { 
    Topic t=new Topic(); 
    t.setId(1); 
    t.setTitle(trs.getString(2)); 
    t.setContent(trs.getString(3)); 
    t.setPublishTime(trs.getTimestamp(4)); 
    t.setPublishIp(trs.getString(5)); 
    ex.setTopic(t); 
//    explains.add(ex); 
    System.out.println( "我的tid: " + tid.getId()); 
   } 
    
   JdbcHelper.release(trs); // 关闭结果集 
   } 
    
    
  } catch (SQLException e) { 
   // TODO Auto-generated catch block 
   e.printStackTrace(); 
  } 
   
   
  session.setAttribute("explains", exp); 
   
  System.out.println( "我的解答列表: " + exp ); 
  System.out.println( "我的id: " + myid); 
  response.sendRedirect( request.getContextPath() + "/myAnswer.html"); 
  } 
 } 
  
 
} 

<!DOCTYPE html> 
<html> 
<head> 
 <meta charset="utf-8" /> 
 <title>解答</title> 
 <link rel="stylesheet" href="$path/styles/top.css"> 
  
</head> 
<body> 
<div > 
<nav id="topnav" class="f_r"> 
 <ul> 
  <a href="$path/index.html"">首页</a> <a href="$path/myQuestion.do" >我的提问</a> 
  <a href="$path/ask.html" >提问</a> <a href="$path/logout.do">注销</a> 
 </ul> 
 </nav> 
 </div> 
#if( $user ) 
$user.username的所有回答： 
#end 
#foreach( $ex in $explains) 
<div class="blogs"> 
<ul> 
 <p>$ex.content</p> 
 <div class="content_time"> 
  <p> 解答时间:<span class="dtime f_l"> $ex.explainTime</span></p> 
 </div> 
 <div class="line"></div> 
</ul> 
</div> 
#end 
 
</body> 
</html> 

@WebServlet("/myQuestion.do") 
public class MyQuestionServlet extends HttpServlet { 
 
 private static final long serialVersionUID = -4110483126223561394L; 
 
 @Override 
 protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
  HttpSession session = request.getSession(); 
  User user = (User) session.getAttribute( "user" ); // 在登录时将 User 对象放入了 会话 中 
  if( user != null ) { 
  int myid=user.getId(); 
  final String SQL = "SELECT id , title , content, publish_time , publish_ip FROM t_topic WHERE user_id = ? "; 
  ResultSet rs = JdbcHelper.query(SQL, myid); 
  final List<Topic> qtopics = new ArrayList<>(); 
  try { 
   while( rs.next() ){ 
   Topic t=new Topic(); 
   t.setId(rs.getInt(1)); 
   t.setTitle(rs.getString(2)); 
   t.setContent(rs.getString(3)); 
   t.setPublishTime(rs.getTimestamp(4)); 
   t.setPublishIp(rs.getString(5)); 
   qtopics.add(t); 
    
    
   } 
  } catch (SQLException e) { 
   // TODO Auto-generated catch block 
   e.printStackTrace(); 
  } 
   
   
  session.setAttribute("qtopics", qtopics); 
   
  System.out.println( "我的提问列表: " + qtopics ); 
  System.out.println( "我的id: " + myid); 
  response.sendRedirect( request.getContextPath() + "/myQuestion.html"); 
  } 
 } 
  
 
} 

<!DOCTYPE html> 
<html> 
<head> 
 <meta charset="utf-8" /> 
 <title>$user.username的提问 </title> 
  <link rel="stylesheet" href="$path/styles/general.css"> 
  <link rel="stylesheet" href="$path/styles/cell.css"> 
  <link rel="stylesheet" href="$path/styles/wen.css"> 
  <link rel="stylesheet" href="$path/styles/top.css"> 
</head> 
<body> 
 
 
<div > 
   <ul> 
   #if($user) 
     <nav id="topnav" class="f_r"> 
      <ul> 
       <a href="$path/index.html">首页</a> 
       <a href="$path/myAnswer.do" >我的解答</a> 
       <a href="$path/ask.html">提问</a> 
       <a href="$path/logout.do" >注销</a> 
      </ul> 
     </nav> 
     #else 
     <li class="presentation"><a href="$path/login.html" id="link" title="提问">登录</a></li> 
    <li class="presentation"><a href="$path/regist.do" id="tools" title="exit">注册</a></li> 
    #end 
   </ul> 
</div> 
 #if( $user ) 
    $user.username的所有提问： 
    #end 
    #foreach( $qto in $qtopics) 
 
<div class="blogs"> 
  <ul> 
   <p>$qto.content</p> 
   <p class="autor"><span class="lm f_l"><a>提问者：$user.username</a></span> <span class="dtime f_l">$qto.publishTime</span></p> 
  </ul> 
   
  </div> 
  #end 
 
</body> 
</html> 

@WebServlet(urlPatterns= { "/verify/login.do" , "/verify/regist.do" } ) 
public class VerifyCodeServlet extends HttpServlet { 
  
 private static final long serialVersionUID = 3398560501558431737L; 
 
 @Override 
 protected void service( HttpServletRequest request , HttpServletResponse response ) 
   throws ServletException, IOException { 
   
  // 获得 当前请求 对应的 会话对象 
  HttpSession session = request.getSession(); 
   
  // 从请求中获得 URI ( 统一资源标识符 ) 
  String uri = request.getRequestURI(); 
  System.out.println( "hello : " + uri ); 
   
  final int width = 180 ; // 图片宽度 
  final int height = 40 ; // 图片高度 
  final String imgType = "jpeg" ; // 指定图片格式 (不是指MIME类型) 
  final OutputStream output = response.getOutputStream(); // 获得可以向客户端返回图片的输出流 (字节流) 
  // 创建验证码图片并返回图片上的字符串 
  String code = GraphicHelper.create( width, height, imgType, output ); 
  System.out.println( "验证码内容: " + code ); 
   
  // 建立 uri 和 相应的 验证码 的关联 ( 存储到当前会话对象的属性中 ) 
  session.setAttribute( uri , code ); 
   
  System.out.println( session.getAttribute( uri ) ); 
   
 } 
 
} 

<!DOCTYPE html> 
<html> 
<head> 
 <meta charset="UTF-8"> 
 <title>注册爱问社区</title> 
 
 <link rel="stylesheet" href="$path/styles/general.css"> 
 <link rel="stylesheet" href="$path/styles/cell.css"> 
 <link rel="stylesheet" href="$path/styles/form.css"> 
 
 <link rel="stylesheet" href="$path/awesome/css/font-awesome.min.css"> 
  
 <script type="text/javascript" src="$path/js/wen.js"></script> 
 
 <style type="text/css" > 
 
  .logo-container { 
   margin-top: 50px ; 
  } 
  .logo-container img { 
   width: 100px ; 
  } 
 
  .message-container { 
   height: 80px ; 
  } 
 
  .link-container { 
   height: 40px ; 
   line-height: 40px ; 
  } 
 
  .link-container a { 
   text-decoration: none ; 
  } 
 
 </style> 
 
</head> 
<body> 
 
<div class="container title-container" >加入爱问社区，为您答疑解惑</div> 
<div class="container form-container"> 
 <form action="$path/regist.do" method="post"> 
  <div class="form"> <!-- 注册表单开始 --> 
 
   <div class="form-row"> 
      <span class="cell-1"> 
       <i class="fa fa-user"></i> 
      </span> 
      <span class="cell-11" > 
       <input type="text" name="username" placeholder="请输入用户名"> 
      </span> 
   </div> 
 
   <div class="form-row"> 
      <span class="cell-1"> 
       <i class="fa fa-key"></i> 
      </span> 
      <span class="cell-11" > 
       <input type="password" name="password" placeholder="请输入密码"> 
      </span> 
   </div> 
 
   <div class="form-row"> 
      <span class="cell-1"> 
       <i class="fa fa-keyboard-o"></i> 
      </span> 
      <span class="cell-11" > 
       <input type="password" name="confirm" placeholder="请确认密码"> 
      </span> 
   </div> 
    
   <div class="form-row"> 
      <span class="cell-7"> 
       <input type="text" name="verifyCode" placeholder="请输入验证码"> 
      </span> 
      <span class="cell-5" > 
       <img src="$path/verify/regist.do" onclick="myRefersh(this)"> 
      </span> 
   </div> 
 
   <div class="form-row" > 
      <span class="cell-6" > 
       <input type="reset" value="重置"> 
      </span> 
      <span class="cell-6" > 
       <input type="submit" value="注册"> 
      </span> 
   </div> 
 
  </div> <!-- 注册表单结束 --> 
 </form> 
</div> 
<div class="container message-container"> 
 <!-- 显示提示信息的地方 --> 
 #if( $registFail ) 
  $registFail 
  $scope.remove( $session , 'registFail' ) 
 #end 
</div> 
<div class="container link-container"> 
 <a href="$path/login.html" > 已注册爱问帐号，点击这里登录</a> 
 | 
 <a href="$path/index.html" >返回首页</a> 
</div> 
<div class="container copyright-container"> 
 &copy; 2017 爱问社区版权所有 
</div> 
 
</body> 
</html> 

@WebServlet("/regist.do") 
public class RegistServlet extends HttpServlet { 
 
 private static final long serialVersionUID = 7493633832455111617L; 
 
 @Override 
 protected void service( HttpServletRequest request , HttpServletResponse response ) 
   throws ServletException, IOException { 
   
  // 获得来自 页面 表单上的数据 
  String verifyCode = request.getParameter( "verifyCode" ) ; // 获得由用户输入的那个验证码 
  String username = request.getParameter( "username" ) ; 
  String password = request.getParameter( "password" ) ; 
  String confirm = request.getParameter( "confirm" ) ; 
   
  System.out.println( "username : " + username ); 
  System.out.println( "password : " + password ); 
  System.out.println( "confirm : " + confirm ); 
  System.out.println( "verifyCode : " + verifyCode ); 
   
  HttpSession session = request.getSession(); 
  // 获得 在 会话 中存储的那个 为登录进行验证的 验证码 
  final String code = (String)session.getAttribute( "/wendao/verify/regist.do" ); 
  System.out.println( "session code : " + code ); 
   
  // 比较验证码 
  if( StringHelper.equals( verifyCode , code ) ){ 
   // 要保证 用户名 不为空 、密码不能为空 、两次输入的密码必须一致 
   if( StringHelper.notEmpty( username ) 
     && StringHelper.notEmpty( password ) 
     && StringHelper.equals( password , confirm) ) { 
    // 可以保存了 
    String SQL = "INSERT INTO t_user ( username , password ) VALUES ( ? , ? ) " ; 
    int n = JdbcHelper.insert( SQL , false , username , StringHelper.MD5(password)); 
    if( n > 0 ) { // 如果 insert 返回 大于 0 的数字 ， 则表示 插入成功 
     // 保存成功以后，应该去一个新的页面 ( 比如去 登录页面 ) 
     response.sendRedirect( request.getContextPath() + "/login.html" ); 
    } else { 
     // 回到注册页面去 
     session.setAttribute( "registFail" , "注册失败，可能是用户名被占用了" ); 
     response.sendRedirect( request.getContextPath() + "/regist.html" ); 
    } 
   } else { 
    // 回到注册页面去 
    session.setAttribute( "registFail" , "用户名或密码为空，或者密码不一致" ); 
    response.sendRedirect( request.getContextPath() + "/regist.html" ); 
   } 
  } else { 
   // 如果验证码不一致，设置提示信息后回到注册页面去 
   session.setAttribute( "registFail" , "验证码输入错误，请重新输入" ); 
   response.sendRedirect( request.getContextPath() + "/regist.html" ); 
  } 
   
 } 
   
} 

@WebServlet("/login.do") 
public class LoginServlet extends HttpServlet { 
 
 private static final long serialVersionUID = 18854422651747352L; 
 
 @Override 
 protected void service( HttpServletRequest request , HttpServletResponse response ) 
   throws ServletException, IOException { 
   
  // 获得来自 页面 表单上的数据 
  String username = request.getParameter( "username" ) ; 
  String password = StringHelper.MD5(request.getParameter( "password" )) ; 
   
  System.out.println( "username : " + username ); 
  System.out.println( "password : " + password ); 
   
  HttpSession session = request.getSession(); 
   
    
   // 登录 : 根据 用户名 和 密码 从数据库中查询数据，如果都正确，就将这些数据放入到会话中，最后进入到指定页面( list.html ) 
   String SQL = "SELECT id , username , password FROM t_user WHERE username = ? and password = ? " ; 
   ResultSet rs = JdbcHelper.query( SQL, username , password ) ; 
    
   try{ 
    // 如果查询到数据，就包装到一个对象中 
    if( rs.next() ) { 
     User user = new User(); // 创建对象 
      
     // 封装数据 
     user.setId( rs.getInt( 1 ) ); 
     user.setUsername( rs.getString( 2 )); 
     user.setPassword( rs.getString( 3 ) ) ; 
     //System.out.println("测试"+MD5.convertMD5(MD5.convertMD5(password))); 
     /** 将 User 对象 放入到 会话中 **/ 
     session.setAttribute( "user" , user ); 
     // 重定向到 list.do ( list.do 会先查询数据后 再 重定向到 list.html ) 
     response.sendRedirect( request.getContextPath() + "/list.do" ); 
    } else { 
     // 如果 用户名 或 密码 错误，重新返回到 登录页面 
      session.setAttribute( "loginFail" , "用户名或密码错误" ); 
     response.sendRedirect( request.getContextPath() + "/login.html" ); 
    } 
   } catch ( SQLException e ){ 
    e.printStackTrace(); 
   } 
 }  
} 

<!DOCTYPE html> 
<html> 
<head> 
 <meta charset="UTF-8"> 
 <title>登录</title> 
 
 <link rel="stylesheet" href="styles/general.css"> 
 <link rel="stylesheet" href="styles/cell.css"> 
 <link rel="stylesheet" href="styles/form.css"> 
 
 <link rel="stylesheet" href="awesome/css/font-awesome.min.css"> 
 <link rel="stylesheet" type="text/css" href="css/login.css"> 
 <script type="text/javascript" src="js/wen.js"></script> 
 
</head> 
<body> 
 <div class="logina-logo" > 
   <div id="venusLogo"><p><span>爱问社区</span></p></div> 
  </div> 
  <div class="logina-main main clearfix"> 
   <div class="tab-con"> 
    <form action="$path/login.do" method="post"> 
     <div id='login-error' class="error-tip"></div> 
     <table border="0" cellspacing="0" cellpadding="0"> 
      <tbody> 
       <tr> 
        <th>账户</th> 
        <td width="245"> 
         <input type="text" name="username" id="username" placeholder="昵称" /> 
        <td> 
        </td> 
       </tr> 
       <tr> 
        <th>密码</th> 
        <td width="245"> 
         <input type="password" name="password" id="password" placeholder="密码" /> 
        </td> 
        <td> 
        </td> 
       </tr> 
       <tr> 
        <th></th> 
        <td width="245"><input class="confirm" type="submit" value="登 录"></td> 
        <td></td> 
       </tr> 
      </tbody> 
     </table> 
    </form> 
   </div> 
   <div class="reg"> 
    <p>还没有账号？<br>赶快免费注册一个吧！</p> 
    <a class="reg-btn" href="regist.html">立即免费注册</a> 
   </div> 
  </div> 
  <div id="footer"> 
   <div class="copyright">Copyright © 爱问社区 版权所有</div> 
  </div>  
</body> 
</html> 

DROP TABLE IF EXISTS `t_explain`; 
CREATE TABLE `t_explain` ( 
 `id` int(11) NOT NULL AUTO_INCREMENT, 
 `content` text, 
 `explain_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP, 
 `explain_ip` varchar(50) DEFAULT NULL, 
 `user_id` int(8) DEFAULT NULL, 
 `topic_id` int(8) DEFAULT NULL, 
 PRIMARY KEY (`id`), 
 KEY `ex_id` (`user_id`), 
 KEY `t_id` (`topic_id`), 
 CONSTRAINT `ex_id` FOREIGN KEY (`user_id`) REFERENCES `t_user` (`id`), 
 CONSTRAINT `t_id` FOREIGN KEY (`topic_id`) REFERENCES `t_topic` (`id`) 
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8; 
 
-- ---------------------------- 
-- Table structure for t_topic 
-- ---------------------------- 
DROP TABLE IF EXISTS `t_topic`; 
CREATE TABLE `t_topic` ( 
 `id` int(10) NOT NULL AUTO_INCREMENT, 
 `title` varchar(255) DEFAULT NULL, 
 `content` text, 
 `publish_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
 `publish_ip` varchar(100) DEFAULT NULL, 
 `user_id` int(10) DEFAULT NULL, 
 PRIMARY KEY (`id`), 
 KEY `cid` (`user_id`), 
 CONSTRAINT `cid` FOREIGN KEY (`user_id`) REFERENCES `t_user` (`id`) 
) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=utf8; 
 
-- ---------------------------- 
-- Table structure for t_user 
-- ---------------------------- 
DROP TABLE IF EXISTS `t_user`; 
CREATE TABLE `t_user` ( 
 `id` int(10) NOT NULL AUTO_INCREMENT, 
 `username` varchar(20) NOT NULL, 
 `password` varchar(255) NOT NULL, 
 PRIMARY KEY (`id`), 
 UNIQUE KEY `username` (`username`) 
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf8;