Ajax-database.zip_ajax连接数据库

package servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.util.*; import java.sql.*; public class AjaxZipCodesServlet extends HttpServlet { public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException { String responseString = null; String zipCode = req.getParameter("zip"); if (zipCode != null) { HashMap location = getCityState(zipCode); responseString = JSONUtil.buildJSON(location, "location"); } if (responseString != null) { //res.setContentType("text/xml"); res.setContentType("application/json"); res.setHeader("Cache-Control", "no-cache"); res.getWriter( ).write(responseString); }else { res.setContentType("text/xml"); res.setHeader("Cache-Control", "no-cache"); res.getWriter( ).write("?"); } } private HashMap getCityState(String zipCode) { Connection con = DatabaseConnector.getConnection( ); HashMap cityStateMap = new HashMap( ); cityStateMap.put("zip", zipCode); String queryString = ""; String city=""; String state=""; try { queryString = "SELECT CITY,STATE FROM ZIPCODES where ZIPCODE=" + zipCode + ";"; Statement select = con.createStatement( ); //cityStateMap.put("city", "city"); ResultSet result = select.executeQuery(queryString); while (result.next( )) { city = result.getString("CITY"); cityStateMap.put("city", city); state = result.getString("state"); cityStateMap.put("state", state); } } catch (Exception e) { System.out.println("exception caught getting city/state:" + queryString + " " + e.getMessage( )); } finally { if (con != null) { try { con.close( ); } catch (SQLException e) { } } } return cityStateMap; } }