• 查询数据库数据并传入servlet


    功能:servlet读取前台要查询的值(des),调用查询函数,得到查到的值的列表,再将列表值传到前台显示。

    servlet:

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            QueryFromMySql queryFromMySql=new QueryFromMySql();  //查询数据库类
            request.setCharacterEncoding("utf-8");  //设置读取编码
            String des=request.getParameter("des");  //通过des查询
            List<CiTiao> ciTiaos=queryFromMySql.SearchByDes(des);
            System.out.println(ciTiaos.get(0).toString());
            int count=queryFromMySql.query();
            System.out.println(count);
            request.setAttribute("citiaos", ciTiaos);   //将查询得到的结果传到前台jsp页面
            request.getRequestDispatcher("/list_sort.jsp").forward(request, response);
        }

    QueryFormMySql:

        private static String DriverName="com.mysql.jdbc.Driver";
        private static String UName="root";
        private static String Upwd="root";
        private static String Url="jdbc:mysql://192.168.25.1:3306/xinjian?useUnicode=true&characterEncoding=UTF-8";
    public List<CiTiao> SearchByDes(String des)  //根据分类查询所有的词条信息
          {
              List<CiTiao> CiTiaos=new ArrayList<CiTiao>();
              CiTiao CiTiao=null;
              Connection conn=null;
              PreparedStatement pstmt=null;
              ResultSet result=null;
              try {
                  Class.forName(DriverName);
                  conn=DriverManager.getConnection(Url, UName, Upwd);
                  String sql="select * from citiao where des like ?";
                  pstmt= conn.prepareStatement(sql);
                  pstmt.setString(1,"%"+des+"%");
                  result=pstmt.executeQuery();
                      while(result.next())
                      {
                           String name=result.getString("name");  //词条名称2
                           des=result.getString("des");  //词条简单内容3
                           String url=result.getString("url");  //词条链接4
                           
                         CiTiao=new CiTiao(name,des,url);
                         CiTiaos.add(CiTiao);
                      }
                  return CiTiaos;
              }
              catch(ClassNotFoundException e)
              {
                  e.printStackTrace();
                  return null;
              } 
              catch (SQLException e) 
              {
                e.printStackTrace();
                return null;
            }
              catch(Exception e)
              {
                  e.printStackTrace();
                  return null;
              }
              finally {
                  try {
                      if(result!=null) result.close();
                      if(pstmt!=null) pstmt.close();
                      if(conn!=null) conn.close();
                  }
                  catch(SQLException e)
                  {
                      e.printStackTrace();
                  }
              }
          }
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  • 原文地址:https://www.cnblogs.com/lq13035130506/p/12326066.html
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