使用JDBC和servlet实现留言的发布和显示

提交的表单用到的JavaScript代码：

<script language="javascript"  >
         function check()
         {  
             if(document.getElementById("name1").value=="null")
            {
                      alert("你现在的用户名为："+document.getElementById("name1").value+"请先登录，再留言！");
                     return false;
             }else{
                     alert("恭喜您："+document.getElementById("name1").value+" 留言发表成功！");
                     return true;
            }
        }

</script>

 

 

发表留言的提交表单：

<!--注意onSubmit的使用，如果JS函数check( )返回的是true，则执行表单的提交；如果返回的是false，就不执行表单的提交-->

<form name="form1" method="post"  action="UserManager" onsubmit="return check();">
               <input type="hidden" name="action" value="ly" /> 
               <input type="hidden" name="name1"  id="name1"  value="<%=(String)request.getSession().getAttribute("user_name")%>" />
               标题：<input type="text" name="title"  value="" size="50"/>
              <textarea style="border-color:#6699FF" name="content" cols="80" rows="4"></textarea><br/>
              <input type="submit" value="发表" align="right"  />
</form>

 

 

servlet中的处理代码：

if("ly".equals(action))

{
            String t=LYservice.nowTime();//在LYservice类中调用静态方法nowTime()获取和格式化系统时间
            LY ly=new LY();//LY为留言的实体类
            ly.setTitle(request.getParameter("title"));
            ly.setContent(request.getParameter("content"));
            ly.setLy_time(t);//留言的时间
            ly.setLy_name((String) request.getSession().getAttribute("user_name"));//获取session中的留言者姓名
    
           LYservice lys=new LYservice();
          try {
         if(lys.FaBiao(ly))
         {
                  request.getRequestDispatcher("customer/ly_1.jsp").forward(request, response);
         }
         } catch (SQLException e) {
                    e.printStackTrace();
         }
 }

 

 

留言相关的业务处理代码：

public class LYservice
{
       public List list_LY()

       {
          java.sql.Connection conn=DB.getConnection();
          ResultSet rs = null;
          try {
   
               String sql = "select * from market_ly";
               Statement sm=conn.createStatement();
               rs = sm.executeQuery(sql);
               LY y = null;
               Vector vector = new Vector();
               // ResultSet指针最初位于第一行之前，调用next方法使下一行成为当前行
              while (rs.next()) {
              y = new LY();
              y.setId(rs.getInt("id"));
              y.setTitle(rs.getString("title"));
              y.setContent(rs.getString("content"));
              y.setLy_name(rs.getString("ly_name"));
              y.setLy_time(rs.getString("ly_time"));
    
             vector.addElement(y);
              }
              return vector;
         } catch (SQLException SqlE) {
              SqlE.printStackTrace();
              return null;
         } catch (Exception E) {
                  E.printStackTrace();
                  return null;
         }
       finally {
                  // 关闭连接，释放数据库资源：
                  DB.close(conn);
        }
    }
 

       //获取并格式化当前系统时间
    public static String nowTime()
    {
                Calendar c = Calendar.getInstance();
                c.setTimeInMillis(new Date().getTime());
                SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                return dateFormat.format(c.getTime());
    }
 
    //发表留言的方法
   public Boolean FaBiao(LY ly) throws SQLException
   {
            Boolean flag=false;
            Connection con = null;
            PreparedStatement pstmt = null;
            //Statement stmt = null;
            con = DB.getConnection();
   
              //stmt=con.createStatement();
              String sql = "insert into market_ly(title,content,ly_name,ly_time) values(?,?,?,?)";
              pstmt = DB.prepare(con, sql);
    
             String title=null;
             String content=null;
             String ly_name=null;
             try {
                     title=new String(ly.getTitle().getBytes("utf-8"), "utf-8");
                      //System.out.println("（转换前）测试1------------"+ly.getContent().getBytes("utf-8"));
                     content=new String(ly.getContent().getBytes("utf-8"), "utf-8");
                     //System.out.println("（转换为uft-8）测试2------------"+content);
                      ly_name=new String(ly.getLy_name().getBytes("utf-8"), "utf-8");
    
             } catch (Exception e) {
                       e.printStackTrace();}
            pstmt.setString(1, title);
            pstmt.setString(2, content);
            pstmt.setString(3, ly_name);
            pstmt.setString(4, ly.getLy_time());
            //String sqltest="insert into market_ly(title,content,ly_name,ly_time) values(\'"
                   //+title+"\',\'"+content+"\',\'"+ly_name+"\',\'"+ly.getLy_time()+"\');";
            System.out.println(sql);
             int a = pstmt.executeUpdate(); 
           //int a=stmt.executeUpdate(sqltest);
           if(a==1)
           {
                 flag=true; 
                 System.out.println("发布留言数据成功！");
           }
           DB.close(pstmt);
           DB.close(con);
           return flag;
  } 
}

 

 

jsp页面中的留言显示代码：

<%     
    LYservice es=new LYservice();
    List<LY> lys=es.list_LY();
    for(LY y:lys)
    {
     
   %>
   <tr>
      <td bgcolor="#FFCCFF" ><span class="STYLE8"><%=y.getId() %></span></td>
      <td bgcolor="#FFCCFF"><span class="STYLE8"><%=y.getTitle() %></span></td>
      <td bgcolor="#FFCCFF"><span class="STYLE8"><%=y.getLy_time() %></span></td>
      <td bgcolor="#FFCCFF"><span class="STYLE8"><%=y.getContent() %></span></td>
      </tr>
     <br/>
     <%
 }
     %>