Java代码

1. package com.lm.org;

• import java.io.IOException;
• import java.io.PrintWriter;
• import java.sql.Connection;
• import java.sql.DriverManager;
• import java.sql.PreparedStatement;
• import java.sql.ResultSet;
• import java.sql.SQLException;
• import javax.servlet.ServletContext;
• import javax.servlet.ServletException;
• import javax.servlet.http.HttpServlet;
• import javax.servlet.http.HttpServletRequest;
• import javax.servlet.http.HttpServletResponse;
• /**

• * Servlet implementation class Test

• */
• public class Test extends HttpServlet {
• private static final long serialVersionUID = 1L;
• /**

• */
• public Test() {
• super();
• }
• /**

• */
• protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
• this.doPost(request, response);

• }
• /**

• */
• protected void doPost(HttpServletRequest request,
• HttpServletResponse response) throws ServletException, IOException {
• request.setCharacterEncoding("utf-8");
• response.setCharacterEncoding("utf-8");
• PrintWriter out = response.getWriter();

• //HttpSession session = request.getSession();// 得到session
• //ServletContext application = super.getServletContext();
• //Integer accessCount = (Integer) application.getAttribute("accessCount");//数据库查询出来

• Integer wiewsCount=null;
• Connection connection = null;
• String sql="select * from t_news where id=1 ";//wiewsCount
• PreparedStatement ps=null;
• ResultSet rs=null;
• try {
• connection=getConnection();
• ps = connection.prepareStatement(sql);
• rs = ps.executeQuery();
• if(rs.next()){
• wiewsCount = rs.getInt("wiewsCount");
• if(wiewsCount==null){
• wiewsCount = 1;
• }else{
• wiewsCount = wiewsCount + 1;
• Connection cn =getConnection();
• String sql1="update t_news set wiewsCount="+wiewsCount+" where id=1";
• PreparedStatement prepareStatement = cn.prepareStatement(sql1);
• int executeUpdate = prepareStatement.executeUpdate();
• if(executeUpdate>0){
• System.out.println("1");
• }else{
• System.out.println(2);
• }
• cn.close();
• cn=null;
• prepareStatement.close();
• prepareStatement=null;
• }
• }
• } catch (SQLException e) {
• e.printStackTrace();
• }finally{
• try {
• connection.close();
• connection=null;
• ps.close();
• ps=null;
• rs.close();
• rs=null;
• } catch (SQLException e) {
• e.printStackTrace();
• }
• }

• Integer ac;
• try {
• ac = accessCount(request, response);
• out.println("模拟值="+ac+"\t数据库值="+wiewsCount);
• } catch (Exception e) {
• e.printStackTrace();
• }
• out.flush();
• out.close();
• }
• public static Integer accessCount(HttpServletRequest request,HttpServletResponse response)throws Exception{
• HttpServletRequest hs=(HttpServletRequest)request;
• ServletContext application = hs.getServletContext();
• Integer accessCount = (Integer) application.getAttribute("accessCount");//数据库查询出来

• //if=null
• if (accessCount == null) {
• accessCount = 1;
• application.setAttribute("accessCount", accessCount);
• } else {
• //else +1并修改数据库的值
• accessCount = accessCount + 1;
• application.setAttribute("accessCount", accessCount);
• //update
• }
• return accessCount;

• }
• /**

• * @return

• */
• public static Connection getConnection() {
• Connection conn = null;
• try {
• Class.forName(Driver);
• conn = DriverManager.getConnection(Url, UserName, PassWord);
• } catch (Exception e) {
• e.printStackTrace();
• }
• return conn;
• }
• private static String Driver = "com.mysql.jdbc.Driver";// ConfigUtils.getProperty("jdbc.driver");
• private static String Url = "jdbc:mysql://localhost:3306/test?characterEncoding=utf8";// ConfigUtils.getProperty("jdbc.url");
• private static String UserName = "root";// ConfigUtils.getProperty("jdbc.userName");
• private static String PassWord = "root";// ConfigUtils.getProperty("jdbc.passWord");
• }