ajax模拟百度自动下拉提示框

import java.io.IOException; import java.io.PrintWriter; import java.net.URLDecoder; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class QueryServlet extends HttpServlet { private static final long serialVersionUID = 1L; public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); String msg = request.getParameter("msg"); String decoded_msg = URLDecoder.decode(msg,"UTF-8"); System.out.println(decoded_msg); getContent(decoded_msg, out); } public static Connection getConnection() { Connection conn = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection( "jdbc:mysql://localhost:3306/autocomplete", "root", "your password"); return conn; } catch (ClassNotFoundException cnfe) { cnfe.printStackTrace(); return null; } catch (SQLException e) { e.printStackTrace(); return null; } } public static void getContent(String msg, PrintWriter out) { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; if ( !msg.equals("")) { System.out.println(msg); String sql = "select * from hotwords where msg like '" + msg + "%'"; System.out.println(sql); try { conn = getConnection(); pstmt = conn.prepareStatement(sql); rs = pstmt.executeQuery(); while (rs.next()) { out.print(rs.getString("msg") + "<br/>"); } } catch (SQLException e) { e.printStackTrace(); }finally { try{ if(rs != null) { rs.close(); } if(pstmt != null) { pstmt.close(); } if(conn != null) { conn.close(); } }catch(SQLException e) { e.printStackTrace(); } } } } //删除内容 public static boolean deleteContent(String msg) { Connection conn = null; PreparedStatement pstmt = null; System.out.println(msg); String sql = "delete * from hotwords where msg =?"; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); pstmt.setString(1,msg); int n = pstmt.executeUpdate(); if ( n > 0) { return true; }else { return false; } } catch (SQLException e) { e.printStackTrace(); return false; }finally { try{ if(pstmt != null) { pstmt.close(); } if(conn != null) { conn.close(); } }catch(SQLException e) { e.printStackTrace(); } } } }