素小暖講hibernate
本文主要講解hibernate框架，ORM的概念和hibernate入門，相信你們看了以後就會使用hibernate了。javascript
欲速則不達，欲達則欲速！html
1、基本概念java
hibernate是一種ORM框架，全稱爲Object_Relative Database-Mapping，在java對象與關係數據庫之間創建某種映射，以實現直接存取java對象。jquery
2、爲何要使用hibernate？spring
既然hibernate是關於java對象和關係數據庫之間的聯繫的話，也就是咱們MVC中的數據持久層DAO層。sql
首先，先來回顧一下編寫DAO層的的經歷：數據庫
- 在DAO層操做XML，將數據封裝到XML文件上，讀寫XML文件數據實現CRUD。
- 在DAO層使用原生JDBC鏈接數據庫，實現CRUD。
- 嫌棄JDBC的connection、statement、resultset等對象太繁瑣，使用對原生JDBC的封裝組件-->DbUtils組件
咱們來看看使用DbUtils以後，程序的代碼是怎麼樣的：express
public class CategoryDAOImpl implements zhongfucheng.dao.CategoryDao{
@Override
publicvoidaddCategory(Category category) {
QueryRunner queryRunner = new QueryRunner(Utils2DB.getDataSource());
String sql = "INSERT INTO category (id, name, description) VALUES(?,?,?)";
try {
queryRunner.update(sql, new Object[]{category.getId(), category.getName(), category.getDescription()});
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Category findCategory(String id) {
QueryRunner queryRunner = new QueryRunner(Utils2DB.getDataSource());
String sql = "SELECT * FROM category WHERE id=?";
try {
Category category = (Category) queryRunner.query(sql, id, new BeanHandler(Category.class));
return category;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public List<Category> getAllCategory() {
QueryRunner queryRunner = new QueryRunner(Utils2DB.getDataSource());
String sql = "SELECT * FROM category";
try {
List<Category> categories = (List<Category>) queryRunner.query(sql, new BeanListHandler(Category.class));
return categories;
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
其實使用DbUtils時，DAO層中的代碼編寫是頗有規律的。apache
- 當插入數據的時候，就將Javabean對象拆分，拼裝成SQL語句
- 當查詢數據的時候，用SQL把數據庫表中的列組合，拼裝成Javabean對象
Javabean對象和數據庫表中的列存在映射關係！若是程序可以自動生成SQL就行了，hibernate應運而生。session
3、hibernate快速入門
學習一個框架無非就是三步：
- 引入jar包
- 配置XML文件
- 熟悉API
一、引入jar包
咱們使用的是Hibernate5.4的版本
hibernate5.jar核心 + required 必須引入的(6個) + jpa 目錄 + 數據庫驅動包
二、配置XML文件
（1）編寫一個Entity對象->Employee.java
編寫對象映射->Employee.hbm.xml。通常它和JavaBean對象放在同一目錄下
在上面的模板上修改～下面會具體講解這個配置文件!
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2020??1??9?? ????9:08:43 by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
<class name="com.ssh.entities.Employee" table="SSH_EMPLOYEE">
<id name="id" type="java.lang.Integer">
<column name="ID" />
<generator class="native" />
</id>
<property name="lastName" type="java.lang.String">
<column name="LASTNAME" />
</property>
<property name="email" type="java.lang.String">
<column name="EMAIL" />
</property>
<property name="birth" type="java.util.Date">
<column name="BIRTH" />
</property>
<property name="createTime" type="java.util.Date">
<column name="CREATE_TIME" />
</property>
<many-to-one name="department" class="com.ssh.entities.Department">
<column name="DEPARTMENT_ID" />
</many-to-one>
</class>
</hibernate-mapping>
（2）主配置文件hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.connection.driverClass">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.username">mine</property>
<property name="hibernate.connection.password">mine</property>
<property name="hibernate.connection.jdbcUrl">jdbc:oracle:thin:@127.0.0.1:1521:orcl</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<mapping resource="com/ssh/entities/Department.hbm.xml"/>
<mapping resource="com/ssh/entities/Employee.hbm.xml"/>
</session-factory>
</hibernate-configuration>
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
<!-- 導入資源文件 -->
<context:property-placeholder location="classpath:db.properties" ignore-unresolvable="true"/>
<!-- 配置c3p0數據源 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="user" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
<property name="driverClass" value="${jdbc.driverClass}"></property>
<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="initialPoolSize" value="${jdbc.initialPoolSize}"></property>
<property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
</bean>
<!-- 定義Hibernate的SessionFactory LocalSessionFactoryBean-->
<bean id="sessionFactory"
class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<!-- 依賴注入數據源，注入上面定義的dataSource -->
<property name="dataSource" ref="dataSource"/>
<!-- mappingResouces屬性用來列出所有映射文件 -->
<property name="mappingResources">
<list>
<!-- 如下用來列出Hibernate映射文件 -->
<value>com/ssh/entities/Department.hbm.xml</value>
<value>com/ssh/entities/Employee.hbm.xml</value>
<value>hibernate.cfg.xml</value>
</list>
</property>
<!-- 定義Hibernate的SessionFactory的屬性 -->
<property name="hibernateProperties">
<props>
<!-- 指定數據庫方言 -->
<prop key="hibernate.dialect">
org.hibernate.dialect.OracleDialect</prop>
<!-- 是否根據須要每次自動建立數據庫 -->
<prop key="hibernate.hbm2ddl.auto">update</prop>
<!-- 顯示Hibernate持久化操做所生成的SQL -->
<prop key="hibernate.show_sql">true</prop>
<!-- 將SQL腳本進行格式化後再輸出 -->
<prop key="hibernate.format_sql">true</prop>
</props>
</property>
</bean>
<!-- 配置spring的聲明式事務
1.配置hibernate的事務管理器 -->
<bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
<!-- <bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager"></bean>
2.配置事務屬性
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="get" read-only="true"/>
<tx:method name="*"/>
</tx:attributes>
</tx:advice> -->
<!-- 3.配置事務切入點，再把事務屬性和事務切入點關聯起來 -->
<!-- <aop:config>
<aop:pointcut expression="execution(* com.guor.ssh.service.*.*(..))" id="txPointcut"/>
<aop:advisor advice-ref="exAdvice" pointcut-ref="txPointcut"/>
</aop:config> -->
</beans>
applicationContext-beans.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="employeeDao" class="com.ssh.dao.EmployeeDao"> <property name="sessionFactory" ref="sessionFactory"></property> </bean> <bean id="departmentDao" class="com.ssh.dao.DepartmentDao"> <property name="sessionFactory" ref="sessionFactory"></property> </bean> <bean id="employeeService" class="com.ssh.service.EmployeeService"> <property name="employeeDao" ref="employeeDao"></property> </bean> <bean id="departmentService" class="com.ssh.service.DepartmentService"> <property name="departmentDao" ref="departmentDao"></property> </bean> <bean id="employeeAction" class="com.ssh.actions.EmployeeAction" scope="prototype"> <property name="employeeService" ref="employeeService"></property> <property name="departmentService" ref="departmentService"></property> </bean> </beans>
struts.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="true" />
<package name="default" namespace="/" extends="struts-default">
<!-- 定義新的攔截器棧， 配置prepare攔截器棧的alwaysInvokePrepare參數值爲false-->
<interceptors>
<interceptor-stack name="sshStack">
<interceptor-ref name="paramsPrepareParamsStack">
<param name="prepare.alwaysInvokePrepare">false</param>
</interceptor-ref>
</interceptor-stack>
</interceptors>
<!-- 使用新的攔截器棧-->
<default-interceptor-ref name="sshStack"></default-interceptor-ref>
<action name="emp-*" class="employeeAction" method="{1}">
<result name="list">/WEB-INF/views/emp-list.jsp</result>
<result type="stream" name="delete">
<param name="contentType">text/html</param>
<param name="inputName">inputStream</param>
</result>
<result name="input">/WEB-INF/views/emp-input.jsp</result>
<result name="success" type="redirect">/emp-list</result>
</action>
</package>
</struts>
三、類文件
EmployeeAction
package com.ssh.actions;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Date;
import java.util.Map;
import org.apache.struts2.interceptor.RequestAware;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.ModelDriven;
import com.opensymphony.xwork2.Preparable;
import com.ssh.entities.Employee;
import com.ssh.service.DepartmentService;
import com.ssh.service.EmployeeService;
public class EmployeeAction extends ActionSupport implements RequestAware,
ModelDriven<Employee>,Preparable{
private static final long serialVersionUID = 1L;
private EmployeeService employeeService;
public void setEmployeeService(EmployeeService employeeService) {
this.employeeService = employeeService;
}
private DepartmentService departmentService;
public void setDepartmentService(DepartmentService departmentService) {
this.departmentService = departmentService;
}
public String list() {
request.put("employees",employeeService.getAll());
return "list";
}
private Integer id;
public void setId(Integer id) {
this.id = id;
}
public InputStream inputStream;
public InputStream getInputStream() {
return inputStream;
}
public String delete() {
try {
employeeService.delete(id);
inputStream = new ByteArrayInputStream("1".getBytes("UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return SUCCESS;
}
public String input() {
request.put("departments", departmentService.getAll());
return INPUT;
}
public void prepareInput() {
if(id!=null) {
model = employeeService.get(id);
}
}
public String save() {
if(id == null) {
model.setCreateTime(new Date());
}
employeeService.saveOrUpdate(model);
System.out.println("model");
return SUCCESS;
}
public void prepareSave() {
if(id == null) {
model = new Employee();
}else {
model = employeeService.get(id);
}
}
private Map<String,Object> request;
@Override
public void setRequest(Map<String, Object> arg0) {
this.request = arg0;
}
@Override
public void prepare() throws Exception {}
private Employee model;
@Override
public Employee getModel() {
return model;
}
}
EmployeeService
package com.ssh.service;
import java.util.List;
import com.ssh.dao.EmployeeDao;
import com.ssh.entities.Employee;
public class EmployeeService {
private EmployeeDao employeeDao;
public void setEmployeeDao(EmployeeDao employeeDao) {
this.employeeDao = employeeDao;
}
public void saveOrUpdate(Employee employee) {
employeeDao.saveOrUpdate(employee);
}
public void delete(Integer id) {
employeeDao.delete(id);
}
public List<Employee> getAll(){
List<Employee> employees = employeeDao.getAll();
return employees;
}
public Employee get(Integer id) {
return employeeDao.get(id);
}
}
EmployeeDao
package com.ssh.dao;
import java.util.List;
import com.ssh.entities.Employee;
public class EmployeeDao extends BaseDao{
public void delete(Integer id) {
String hql = "DELETE From Employee e where e.id=?0";
getSession().createQuery(hql).setParameter(0,id).executeUpdate();
}
public List<Employee> getAll() {
//String hql = "From Employee e LEFT OUTER JOIN FETCH e.department";
String hql = "From Employee";
return getSession().createQuery(hql).list();
}
public void saveOrUpdate(Employee employee) {
getSession().saveOrUpdate(employee);
}
public Employee get(Integer id) {
return (Employee)getSession().get(Employee.class,id);
}
}
emp-list.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src = "js/jquery-2.1.4.min.js"></script>
<script type="text/javascript">
$(function(){
$(".delete").click(function(){
var lastName = $(this).next(":input").val();
var flag = confirm("肯定要刪除"+lastName+"的信息嗎？");
if(flag){
var $tr = $(this).parent().parent();
var url = this.href;
var args = {"time":new Date()}
$.post(url,args,function(data){
if(data=="1"){
alert("刪除成功!");
$tr.remove();
}else{
alert("刪除失敗!");
}
});
}
return false;
})
})
</script>
</head>
<body>
<h4>Employee List Page</h4>
<s:if test="#request.employees == null||#request.employees.size() == 0">
沒有任何員工信息
</s:if>
<s:else>
<table border="1" cellpadding="10" cellspacing="0">
<tr>
<td>ID</td>
<td>LASTNAME</td>
<td>EMAIL</td>
<td>BIRTH</td>
<td>CREATETIME</td>
<td>delete</td>
<td>edit</td>
</tr>
<s:iterator value="#request.employees">
<tr>
<td>${id }</td>
<td>${lastName }</td>
<td>${email }</td>
<td>${birth }</td>
<td>${createTime }</td>
<td>
<a href="emp-delete?id=${id } " class="delete">Delete</a>
<input type="hidden" value="${lastName }"/>
</td>
<td><a href="emp-input?id=${id }">Edit</a></td>
</tr>
</s:iterator>
</table>
</s:else>
</body>
</html>
emp-input.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h4>Employee Input Page</h4>
<s:form action="emp-save" method="post">
<s:if test="id != null">
<s:textfield name="lastName" label="LastName" disabled="true"></s:textfield>
<s:hidden name="id"></s:hidden>
</s:if>
<s:else>
<s:textfield name="lastName" label="LastName"></s:textfield>
</s:else>
<s:textfield name="email" label="Email"></s:textfield>
<s:textfield name="birth" label="Birth"></s:textfield>
<s:select list="#request.departments"
listKey="id" listValue="departmentName"
name="department.id" label="Department">
</s:select>
<s:submit></s:submit>
</s:form>
</body>
</html>
4、完成hibernate增刪改查
5、configuration
一、配置管理類：主要管理配置文件的一個類
它擁有一個子類annotationConfiguration，也就是說咱們可使用註解來代替XML配置文件來配置相對應的信息。
二、方法
（1）configure方法用於加載配置文件：
- 若是指定參數，那麼加載參數的路徑配置文件
- 若是不指定參數，默認加載src/目錄下的hibernate.cfg.xml
（2）buildSessionFactory()用於建立session工廠
（3）sessionFactory方法
SessionFactory-->Session的工廠，也能夠說表明了hibernate.cfg.xml這個文件...hibernate.cfg.xml的就有<session-factory>這麼一個節點
（4）openSession方法，建立一個session對象
（5）getCurrentSession方法，建立session對象或取出session對象
三、session
session是hibernate最重要的對象，session維護了一個鏈接（connection），只要使用hibernate操做數據庫，都須要使用session對象。
更新操做
使用save方法，調用這個方法把對象保存在數據庫中，session對象提供其餘方法進行對數據庫的更新
- session.save(obj); 【保存一個對象】
- session.update(obj); 【更新一個對象】
- session.saveOrUpdate(obj); 【保存或者更新的方法】
- 沒有設置主鍵，執行保存；
- 有設置主鍵，執行更新操做;
- 若是設置主鍵不存在報錯！
6、HQL查詢
一、HQL：hibernate query language即hibernate提供的面向對象的查詢語言
查詢的是對象以及對象的屬性，區分大小寫
二、SQL：strut query language結構化查詢語言。不區分大小寫
三、本地SQL查詢
有的時候，若是SQL是很是複雜的，咱們不能靠SQL查詢來實現功能的話，咱們就須要使用原生的SQL進行復雜查詢，可是它有一個缺陷，不能跨平臺，所以咱們在主配置文件中已經配置了數據庫的「方言」了。
//將全部的記錄封裝成User對象存進List集合中
SQLQuery sqlQuery = session.createSQLQuery("SELECT * FROM user").addEntity(User.class);
List list = sqlQuery.list();
System.out.println(list);
6、beginTransaction方法
開啓事務，返回的是一個事務對象，hibernate規定全部的數據庫都必須在事務環境下進行，否者報錯！
數據庫配置
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.connection.driverClass">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.username">mine</property>
<property name="hibernate.connection.password">mine</property>
<property name="hibernate.connection.jdbcUrl">jdbc:oracle:thin:@127.0.0.1:1521:orcl</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<mapping resource="com/ssh/entities/Department.hbm.xml"/>
<mapping resource="com/ssh/entities/Employee.hbm.xml"/>
</session-factory>
其它參數配置
<!-- 定義Hibernate的SessionFactory的屬性 -->
<property name="hibernateProperties">
<props>
<!-- 指定數據庫方言 -->
<prop key="hibernate.dialect">
org.hibernate.dialect.OracleDialect</prop>
<!-- 是否根據須要每次自動建立數據庫 -->
<prop key="hibernate.hbm2ddl.auto">update</prop>
<!-- 顯示Hibernate持久化操做所生成的SQL -->
<prop key="hibernate.show_sql">true</prop>
<!-- 將SQL腳本進行格式化後再輸出 -->
<prop key="hibernate.format_sql">true</prop>
</props>
</property>
加載映射文件
<property name="mappingResources">
<list>
<!-- 如下用來列出Hibernate映射文件 -->
<value>com/ssh/entities/Department.hbm.xml</value>
<value>com/ssh/entities/Employee.hbm.xml</value>
<value>hibernate.cfg.xml</value>
</list>
</property>
7、hibernate執行流程圖
SSH項目源碼：
連接: https://pan.baidu.com/s/1BK0V1wxA-GQrWco10WEzeg 提取碼: 2e3e
推薦博客
相關文章
- 1. 素小暖講Java
- 2. 素小暖講微服務
- 3. 素小暖講Spring Boot
- 4. 素小暖講Spring JdbcTemplate
- 5. 素小暖講重構
- 6. 素小暖講Java框架（SSH、SSM、Springboot）
- 7. 素小暖講JVM：HotSpot VM GC 的種類
- 8. 素小暖講JVM：JVM內存調優
- 9. 素小暖講設計模式
- 10. 素小暖講JVM：Eclipse運行速度調優
- 更多相關文章...
- • Hibernate悲觀鎖 - Hibernate教程
- • Hibernate是什麼 - Hibernate教程
- • 爲了進字節跳動，我精選了29道Java經典算法題，帶詳細講解
- • 算法總結-歸併排序
相關標籤/搜索
每日一句
-
每一个你不满意的现在，都有一个你没有努力的曾经。
歡迎關注本站公眾號,獲取更多信息
相關文章
- 1. 素小暖講Java
- 2. 素小暖講微服務
- 3. 素小暖講Spring Boot
- 4. 素小暖講Spring JdbcTemplate
- 5. 素小暖講重構
- 6. 素小暖講Java框架（SSH、SSM、Springboot）
- 7. 素小暖講JVM：HotSpot VM GC 的種類
- 8. 素小暖講JVM：JVM內存調優
- 9. 素小暖講設計模式
- 10. 素小暖講JVM：Eclipse運行速度調優