JPA学习 —— 第三课、spring整合JPA （完全版）

Dear 丶 2022-05-25 02:09 264阅读 0赞

**1.配置依赖**

<properties>
            <mysql.version>5.1.34</mysql.version>
            <spring.version>4.3.0.RELEASE</spring.version>
            <hibernate.version>4.1.0.Final</hibernate.version>
            <querydsl.version>4.1.4</querydsl.version>
            <jackson.version>2.5.4</jackson.version>
        </properties>
        <dependencies>
            
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>3.1.0</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-core</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context-support</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-orm</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-tx</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-test</artifactId>
                <version>${spring.version}</version>
            </dependency>
            
    
            
            
            <dependency>
                <groupId>com.mchange</groupId>
                <artifactId>c3p0</artifactId>
                <version>0.9.5.2</version>
            </dependency>
            
    
            
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-core</artifactId>
                <version>${hibernate.version}</version>
            </dependency>
    
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-entitymanager</artifactId>
                <version>${hibernate.version}</version>
            </dependency>
            
    
            
            
            
            <dependency>
                <groupId>aopalliance</groupId>
                <artifactId>aopalliance</artifactId>
                <version>1.0</version>
            </dependency>
            
            <dependency>
                <groupId>cglib</groupId>
                <artifactId>cglib</artifactId>
                <version>2.2.2</version>
            </dependency>
            
            <dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjweaver</artifactId>
                <version>1.6.8</version>
            </dependency>
            
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
            
            
            <dependency>
                <groupId>org.apache.commons</groupId>
                <artifactId>commons-lang3</artifactId>
                <version>3.3.2</version>
            </dependency>
            
        </dependencies>

这里比之前不完全版就是多了事务配置相关依赖

**2.配置 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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
    
        
        <context:component-scan base-package="com.ssj"></context:component-scan>
    
        
        <context:property-placeholder location="classpath:jdbc.properties" />
    
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            <property name="user" value="${jdbc.user}"></property>
            <property name="password" value="${jdbc.password}"></property>
            <property name="driverClass" value="${jdbc.driverClass}"></property>
            <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
            
        </bean>
    
        
        <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
            <property name="dataSource" ref="dataSource"></property>
            <property name="jpaVendorAdapter">
                <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>
            </property>
            <property name="packagesToScan" value="com.ssj.domain"></property>
            <property name="jpaProperties">
                <props>
                    
                    <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                    
                    <prop key="hibernate.hbm2ddl.auto">update</prop>
                    
                    <prop key="hibernate.show_sql">true</prop>
                    
                    <prop key="hibernate.format_sql">true</prop>
                    
                    <prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>
    
                     
                </props>
            </property>
        </bean>
        
        <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
            <property name="entityManagerFactory" ref="entityManagerFactory"></property>
        </bean>
    
        
        <tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true" />
    
        
        <tx:advice id="txAdvice" transaction-manager="transactionManager">
            <tx:attributes>
                <tx:method name="insert*" propagation="REQUIRED" />
                <tx:method name="save*" propagation="REQUIRED" />
                <tx:method name="update*" propagation="REQUIRED" />
                <tx:method name="delete*" propagation="REQUIRED" />
                <tx:method name="get*" propagation="SUPPORTS" read-only="true" />
                <tx:method name="find*" propagation="SUPPORTS" read-only="true" />
                <tx:method name="select*" propagation="SUPPORTS" read-only="true" />
                <tx:method name="load*" propagation="SUPPORTS" read-only="true" />
                
                <tx:method name="*" />
            </tx:attributes>
        </tx:advice>
        
        <aop:config proxy-target-class="true">
            <aop:pointcut expression=" execution(* com.ssj.service..*(..))" id="serviceMethod" />
            <aop:advisor advice-ref="txAdvice" pointcut-ref="serviceMethod" />
        </aop:config>
    
    </beans>

这里配置了事务控制，主要是监控service中的方法，通过方法前缀进行匹配。这样开发者就不用再管事务相关的内容了，全交给spring容器进行管理了。

**3.实体类**

package com.ssj.domain;
    
    import java.util.Date;
    
    import javax.persistence.*;
    
    @Entity
    @Table(name="employee")
    public class Employee { 
    
        @Column(name="ID")
        @GeneratedValue(strategy=GenerationType.IDENTITY)
        @Id
        private Integer Id;
    
        @Column(name="EMP_NAME")
        private String empName;
    
        @Column(name="EMP_BIRTH")
        @Temporal(TemporalType.DATE)
        private Date empBirth;
    
    
        public Integer getId() {
            return Id;
        }
        public void setId(Integer id) {
            Id = id;
        }
        public String getEmpName() {
            return empName;
        }
        public void setEmpName(String empName) {
            this.empName = empName;
        }
    
        public Date getEmpBirth() {
            return empBirth;
        }
        public void setEmpBirth(Date empBirth) {
            this.empBirth = empBirth;
        }
        @Override
        public String toString() {
            return "Employee [Id=" + Id + ", empName=" + empName + ", empBirth="
                    + empBirth + "]";
        }
    }

**4.dao层**

package com.ssj.dao;
    
    import javax.persistence.EntityManager;
    import javax.persistence.PersistenceContext;
    
    import org.springframework.stereotype.Repository;
    
    import com.ssj.domain.Employee;
    
    @Repository
    public class EmployeeDao { 
    
        @PersistenceContext
        private EntityManager em;
    
        public void save(Employee emp){
            em.persist(emp);
        }
    }

**5.service层**

package com.ssj.service;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import com.ssj.dao.EmployeeDao;
    import com.ssj.domain.Employee;
    
    @Service
    public class EmployeeService {
    
        @Autowired
        private EmployeeDao employeeDao;
    
        public void save(Employee emp){
            employeeDao.save(emp);
        }
    }

**6.测试类**

package com.ssj.test;
    
    import java.util.Date;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    import com.ssj.domain.Employee;
    import com.ssj.service.EmployeeService;
    
    @RunWith(SpringJUnit4ClassRunner.class)  
    @ContextConfiguration(locations= "classpath:applicationContext.xml") 
    public class Test01 {
    
        @Autowired
        private EmployeeService employeeService;
    
        @Test
        public void test1(){
            Employee emp = new Employee();
            emp.setEmpName("李四");
            emp.setEmpBirth(new Date());
            employeeService.save(emp);
        }
    
    }

7.测试结果  
![这里写图片描述][70]  
数据库  
![这里写图片描述][70 1]

总结：这里比之前不完全版就多了个事务的配置,将事务控制交给spring容器管理,开发者就不用关注事务相关内容。  
开发时直接注入使用EntityManage，而不用再通过工厂方法获取。  
@PersistenceContext  
private EntityManager em;

注:之前用的hibernate5，但是有个配置是只在5以下才有效,所以改成了hibernate4

<prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>

命名规范的设置在hibernate5中改了,这里就不详细说了，有兴趣的朋友可以自己去研究下。  
注:之前配置hibernate方言使用的是org.hibernate.dialect.MySQLMyISAMDialect就是告诉MySQL数据库使用MyISAM引擎。但是使用这个引擎创建的数据表总是生成不了外键，查了一些资料才知道:  
**MyISAM类型不支持事务处理和外键等高级处理，而InnoDB类型支持。MyISAM类型的表强调的是性能，其执行数度比InnoDB类型更快，但是不提供事务支持，而InnoDB提供事务支持以及外键等高级数据库功能。**  
所以后来就改为了使用InnoDB

<prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>

但是使用这个又出现个问题,新建表失败。  
原来是我的MySql数据库美誉开启InnoDB的缘故。  
开启方法:  
修改MySQL安装目录下的my.ini，在skip-innodb前增加\#，重启MySQL即可。  
重启:  
Windows  
　　1.点击“开始”->“运行”(快捷键Win+R),cmd。  
　　2.停止：输入 net stop mysql  
3.启动：输入 net start mysql

[70]: /images/20220525/1905286b8ac64160bf72b18fd4f0ddbf.png
[70 1]: /images/20220525/f848d08e3d9d441d8f3f3fb025e1b7bc.png