如何从数据库中检索数据并使用jdbc连接将其显示在jsp文本字段中

Question

I am retrieving data from database and displaying it in table in a JSP but I do not have any idea about how to display it on text fields.

eg

1. when I search a index number.
2. the the result (name , address, age) must come to the textfeilds which are in my JSP

My code:

public class S2 extends HttpServlet {


protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    Connection conn = null;
    String url = "jdbc:mysql://localhost:3306/";
    String dbName = "shoppingCart";
    String driver = "com.mysql.jdbc.Driver";
    String userName = "root";
    String password = "";

    Statement st;
    try {
        Class.forName(driver).newInstance();
        conn = DriverManager.getConnection(url + dbName, userName, password);
        System.out.println("Connected!");
        String pid = request.getParameter("pid");

        ArrayList al = null;
        ArrayList pid_list = new ArrayList();
        String query = "select * from user where uid='" + pid + "' ";

        System.out.println("query " + query);
        st = conn.createStatement();
        ResultSet rs = st.executeQuery(query);

        while (rs.next()) {

            al = new ArrayList();

            out.println(rs.getString(1));
            out.println(rs.getString(2));
            out.println(rs.getString(3));
            out.println(rs.getString(4));
            out.println(rs.getString(5));


            al.add(rs.getString(1));
            al.add(rs.getString(2));
            al.add(rs.getString(3));
            al.add(rs.getString(4));
            al.add(rs.getString(5));


            System.out.println("al :: " + al);
            pid_list.add(al);
        }


        request.setAttribute("piList", pid_list);
        RequestDispatcher view = request.getRequestDispatcher("/searchview.jsp");
        view.forward(request, response);
        conn.close();
        System.out.println("Disconnected!");
    } catch (Exception e) {
        e.printStackTrace();
    }

Answer 1

Make sure you have included the jdbc driver in your project and "build" it. Then:

1. Make the database connection and retrieve the query result.

2. Return the query result and save in an object of ResultSet.

3. Traverse through the object and display the query results.

The example code below demonstrates this in detail.

String label = request.getParameter("label"); 
//retrieving a variable from a previous page

Connection dbc = null; //Make connection to the database
Class.forName("com.mysql.jdbc.Driver");
dbc = DriverManager.getConnection("jdbc:mysql://localhost:3306/works", "root", "root");

if (dbc != null) 
{
    System.out.println("Connection successful");
}
ResultSet rs = listresult.dbresult.func(dbc, label); 
//The above function is mentioned in the end. 
//It is defined in another package- listresult

while (rs.next()) 
{
%>
<form name="demo form" method="post">
    <table>
        <tr>
            <td>
                Label Name:
            </td>
            <td>
                <input type="text" name="label" 
                value="<%=rs.getString("lname")%>">
            </td>
        </tr>
    </table>
</form>
<% } %>


public static ResultSet func(Connection dbc, String x)
{
    ResultSet rs = null;
    String sql;
    PreparedStatement pst;
    try
    {
        sql = "select lname from demo where label like '" + x + "'";
        pst = dbc.prepareStatement(sql);
        rs = pst.executeQuery();
    } 
    catch (Exception e) 
    {
        e.printStackTrace();
        String sqlMessage = e.getMessage();
    }
    return rs;
}

I have tried to make this example as detailed as possible. If any queries do ask.

Answer 2

<input type="text" value=<%=rs.getString("table_coloumn_name")%>></input>

Answer 3

Add the retrieved value to a request or session object and retrieve it on the JSP page using scrip lets and expressions. or you can try using JSTL/EL too like below

In the handler or servlet add the retrieved value from database to request object

request.setAttribute(theValueFromDB, "value");

then forward or redirect the page to the corresponding JSP. In the JSP page

<input type="text" value="${ requestScope.value}">

Answer 4

Which database you are using? For example, MySQL and MS Access each has a different method to connect to the database.

If you can make a connection, then do the following

• make an object of class that is querying to database
• call the function that will query database
• return the query result and save in an object of mySqlQuery
• now retrieve the rows and display each column in fields you want.

If you have any problems, I can provide you code to fix it.

Answer 5

while(!rs1.next() && !rs2.next()) {

            %>
            <td><input type="checkbox" name="pteam" value=<%=rs1.getString("ename")%>>emp_name:  </td>
            <%x++;}}st.close();con.close();%>