Hibernate實現CRUD（附項目源碼）

本文主要講解hibernate框架，ORM的概念和hibernate入門，相信大家看了之後就會使用hibernate了。

一、基本概念

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建立某種映射，以實現直接存取java對象。

二、爲什麼要使用hibernate？

既然hibernate是關於java對象和關係數據庫之間的聯繫的話，也就是我們MVC中的數據持久層DAO層。

首先，先來回顧一下編寫DAO層的的經歷：

在DAO層操作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連接數據庫，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
我們來看看使用DbUtils之後，程序的代碼是怎麼樣的：

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層中的代碼編寫是很有規律的。

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！如果程序能夠自動生成SQL就好了，hibernate應運而生。

三、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

1、引入jar包

我們使用的是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

2、配置XML文件

（1）編寫一個Entity對象->Employee.java

編寫對象映射->Employee.hbm.xml。一般它和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屬性用來列出全部映射文件 -->
        <property name="mappingResources">
            <list>
                <!-- 以下用來列出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>
                <!-- 是否根據需要每次自動創建數據庫 -->
                <prop key="hibernate.hbm2ddl.auto">update</prop>
                <!-- 顯示Hibernate持久化操作所生成的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>

3、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("確定要刪除"+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>

四、完成hibernate增刪改查

 

五、configuration

1、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，也就是說我們可以使用註解來代替XML配置文件來配置相對應的信息。

2、方法

（1）configure方法用於加載配置文件：

如果指定參數，那麼加載參數的路徑配置文件
如果不指定參數，默認加載src/目錄下的hibernate.cfg.xml
（2）buildSessionFactory()用於創建session工廠

（3）sessionFactory方法

SessionFactory-->Session的工廠，也可以說代表了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，創建一個session對象

（5）getCurrentSession方法，創建session對象或取出session對象

3、session

session是hibernate最重要的對象，session維護了一個連接（connection），只要使用hibernate操作數據庫，都需要使用session對象。

更新操作

使用save方法，調用這個方法把對象保存在數據庫中，session對象提供其他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，執行更新操作;
• 如果設置主鍵不存在報錯！

六、HQL查詢

1、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

2、SQL

strut query language結構化查詢語言。不區分大小寫

3、本地SQL查詢

有的時候，如果SQL是非常複雜的，我們不能靠SQL查詢來實現功能的話，我們就需要使用原生的SQL進行復雜查詢，但是它有一個缺陷，不能跨平臺，因此我們在主配置文件中已經配置了數據庫的“方言”了。

//將所有的記錄封裝成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);

 六、beginTransaction方法

開啓事務，返回的是一個事務對象，hibernate規定所有的數據庫都必須在事務環境下進行，否者報錯！

1、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>

2、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>
        <!-- 是否根據需要每次自動創建數據庫 -->
        <prop key="hibernate.hbm2ddl.auto">update</prop>
        <!-- 顯示Hibernate持久化操作所生成的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>

3、加載映射文件

<property name="mappingResources">
    <list>
        <!-- 以下用來列出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>

七、hibernate執行流程圖

 

尚硅谷Java視頻_SSH整合&綜合案例 視頻教程

SSH項目源碼：

鏈接: https://pan.baidu.com/s/1BK0V1wxA-GQrWco10WEzeg 提取碼: 2e3e