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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