Javaweb常用工具类及配置文件备份
做一个代码备份，以后常用到的。
hibernate工具类备份
package com.dly.service;
/*
* hibernate获取session 的工具类
*/
import java.io.Serializable;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.Session;
public final class HibernateUtil {
private static SessionFactory sessionFactory;
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
private HibernateUtil(){
}
static{
Configuration cfg=new Configuration();
cfg.configure();//配置文件名
sessionFactory=cfg.buildSessionFactory();
}
public static Session getSession(){
return sessionFactory.openSession();
}
/**
* 添加信息
* @param entity
*/
public static void add(Object entity){
Session s=null;
Transaction tx=null;
try{
s=HibernateUtil.getSession();
tx=s.beginTransaction();
s.save(entity);
tx.commit();
}finally{
if(s!=null){
s.close();
}
}
}
/**
* 更新信息
* @param entity
*/
public static void update(Object entity){
Session s=null;
Transaction tx=null;
try{
s=HibernateUtil.getSession();
tx=s.beginTransaction();
s.update(entity);
tx.commit();
}finally{
if(s!=null){
s.close();
}
}
}
/**
* 删除信息
* @param entity
*/
public static void delete(Object entity){
Session s=null;
Transaction tx=null;
try{
s=HibernateUtil.getSession();
tx=s.beginTransaction();
s.delete(entity);
tx.commit();
}finally{
if(s!=null){
s.close();
}
}
}
/**
* 根据id查询
* @param clazz
* @param id
* @return
*/
public static Object get(Class clazz,Serializable id){
Session s=null;
try{
s=HibernateUtil.getSession();
Object obj=s.get(clazz, id);
return obj;
}finally{
if(s!=null){
s.close();
}
}
}
}
操作数据库举例：
package com.dly.service;
import java.util.List;
import org.hibernate.Query;
import org.hibernate.Session;
import com.dly.entity.Users;
public class UserDao {
public static String queryByname(String name){
Session s=null;
String result=null;
//System.out.println("调用了");
try{
s=HibernateUtil.getSession();
String hql="from Users as user where user.username=:username";//里面User是类名，不是表名，为类名起别名user，查询的是对象
Query query=s.createQuery(hql);
query.setString("username", name);
Users u=(Users) query.uniqueResult();//确定只有一个数据，限制用户名唯一时使用
// System.out.println(u.getUsername());
if(u!=null){
result=u.getUsername();
System.out.println(result);
}
return result;
}finally{
if(s!=null){
s.close();
}
}
}
public static Users queryByusername(String username,String pwd){
Users user=null;
Session s=null;
try{
s=HibernateUtil.getSession();
String hql="from Users as users where users.username=:username";//里面User是类名，不是表名，为类名起别名user，查询的是对象
Query query=s.createQuery(hql);
query.setString("username", username);
List<Users>list =query.list();
for(Users users:list){
String u=users.getUsername();
String p=users.getPassword();
if(u.equals(username)&&p.equals(pwd)){
user=users;
}
}
return user;
}finally{
if(s!=null){
s.close();
}
}
}
}
servlet常用代码举例：
package com.dly.servlet;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.JSONArray;
import com.dly.entity.Shop;
import com.dly.service.BuyCarDao;
import com.dly.service.HibernateUtil;
@WebServlet("/BuyCarList")
public class BuyCarList extends HttpServlet {
private static final long serialVersionUID = 1L;
// Class clazz=BuyCar.class;
Class<Shop> clazz=Shop.class;
List<Shop> shop=new ArrayList<Shop>();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
int userid=Integer.parseInt(request.getParameter("userid"));
List<Integer> list=new ArrayList<Integer>();
list=BuyCarDao.querayByuserid(userid);
Iterator<Integer> it=list.iterator();
List<Shop>shop=new ArrayList<Shop>();
while(it.hasNext()){
int shopid=(Integer) it.next();
shop.add((Shop) HibernateUtil.get(clazz, shopid));
}
JSONArray shoplist=new JSONArray(shop);
response.getWriter().println(shoplist.toString());
}
}
package com.dly.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dly.entity.BuyCar;
import com.dly.service.BuyCarDao;
import com.dly.service.HibernateUtil;
@WebServlet("/AddBuyCar")
public class AddBuyCar extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
BuyCar buycar;
int shopid = Integer.parseInt(request.getParameter("shopid"));
int userid=Integer.parseInt(request.getParameter("userid"));
BuyCar result =BuyCarDao.queryByshopid(shopid);
if(result==null){
buycar=new BuyCar();
buycar.setShopid(shopid);
buycar.setUserid(userid);
HibernateUtil.add(buycar);
response.getWriter().print("添加成功");
response.getWriter().flush();
}else{
response.getWriter().print("该商品已在购物车中");
response.getWriter().flush();
}
}
}
hibernate配置文件编写
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- 映射文件 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/trade?useUnicode=true&characterEncoding=UTF-8</property> <property name="connection.username">root</property> <property name="connection.password"></property> <property name="dialect"> org.hibernate.dialect.MySQLDialect</property> <mapping resource="com/dly/entity/Users.hbm.xml"/> </session-factory> </hibernate-configuration>
Users.hbm.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.dly.entity"> <class name="Users" table="users" > <!-- id值 --> <id name="userid" type="int" length="11"> <generator class="native"/> </id> <property name="username" type="string" length="32" column="username"></property> <property name="password" type="string" length="32" column="password"></property> <property name="school" type="string" length="64" column="school"></property> <property name="userphone" type="string" length="32" column="userphone"></property> </class> </hibernate-mapping>
此代码正在完善中。。。。。。
