Spring Data JPA 2. HelloWorld

偏执的太偏执、 2022-05-21 08:18 157阅读 0赞

# Spring Data JPA HelloWorld #

## 使用 Spring Data JPA 进行持久层开发需要的四个步骤： ##

*  配置 Spring 整合 JPA
 *  在 Spring 配置文件中配置 Spring Data，让 Spring 为声明的接口创建代理对象。配置了 `<jpa:repositories>` 后，Spring 初始化容器时将会扫描 base-package 指定的包目录及其子目录，为继承 Repository 或其子接口的接口创建代理对象，并将代理对象注册为 Spring Bean，业务层便可以通过 Spring 自动封装的特性来直接使用该对象。
 *  声明持久层的接口，该接口继承 Repository，Repository 是一个标记型接口，它不包含任何方法，如必要，Spring Data 可实现 Repository 其他子接口，其中定义了一些常用的增删改查，以及分页相关的方法。
 *  在接口中声明需要的方法。Spring Data 将根据给定的策略（具体策略稍后讲解）来为其生成实现代码。

## 搭建环境 ##

*  pom.xml

<?xml version="1.0" encoding="UTF-8"?>
    
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
    
      <groupId>com.ifox.hgx</groupId>
      <artifactId>springData</artifactId>
      <version>1.0-SNAPSHOT</version>
      <packaging>war</packaging>
    
      <name>springData Maven Webapp</name>
      
      <url>http://www.example.com</url>
    
      <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
      </properties>
    
      <dependencies>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-core</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-beans</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-web</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-webmvc</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-jdbc</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-orm</artifactId>
          <version>5.0.3.RELEASE</version>
        </dependency>
    
    
        
        <dependency>
          <groupId>org.hibernate</groupId>
          <artifactId>hibernate-core</artifactId>
          <version>5.2.13.Final</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.hibernate</groupId>
          <artifactId>hibernate-entitymanager</artifactId>
          <version>5.2.13.Final</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.springframework.data</groupId>
          <artifactId>spring-data-jpa</artifactId>
          <version>2.0.3.RELEASE</version>
        </dependency>
    
    
        
        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.38</version>
        </dependency>
    
        
        <dependency>
          <groupId>com.mchange</groupId>
          <artifactId>c3p0</artifactId>
          <version>0.9.5.2</version>
        </dependency>
    
        
        <dependency>
          <groupId>org.slf4j</groupId>
          <artifactId>slf4j-log4j12</artifactId>
          <version>1.7.25</version>
          <scope>test</scope>
        </dependency>
    
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.11</version>
          <scope>test</scope>
        </dependency>
      </dependencies>

*  配置文件: 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: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/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
    
    
        
        <context:component-scan base-package="com.ifox.hgx.springdata"></context:component-scan>
    
        
        <context:property-placeholder location="classpath:db.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.url}"></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.ifox.hgx.springdata"></property>
            <property name="jpaProperties">
                <props>
                    
                    
                    
                    <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                    
                    <prop key="hibernate.dialect">org.hibernate.dialect.MySQL57Dialect</prop>
                    <prop key="hibernate.show_sql">true</prop>
                    <prop key="hibernate.format_sql">true</prop>
                    <prop key="hibernate.hbm2ddl.auto">update</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"/>
    
        
        
        
        <jpa:repositories base-package="com.ifox.hgx.springdata" entity-manager-factory-ref="entityManagerFactory"></jpa:repositories>
    </beans>

*  数据库连接配置:db.properties

jdbc.url = jdbc:mysql://localhost:3306/JPA?useSSL=true
    jdbc.user = root
    jdbc.password = 123456
    jdbc.driverClass = com.mysql.jdbc.Driver

*  log4j配置文件:log4j.properties

log4j.rootLogger=WARN, stdout, R
    log4j.appender.stdout=org.apache.log4j.ConsoleAppender
    log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
    log4j.appender.stdout.layout.ConversionPattern=%d [%t] %-5p %c - %m%n
    log4j.appender.R=org.apache.log4j.RollingFileAppender
    log4j.appender.R.File=example.log
    log4j.appender.R.MaxFileSize=100KB
    log4j.appender.R.MaxBackupIndex=1
    log4j.appender.R.layout=org.apache.log4j.PatternLayout
    log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n
    log4j.logger.com.foo=WARN

## HelloWorld ##

*  entity实体类:Person

package com.ifox.hgx.springdata.entities;
    
    import org.springframework.format.annotation.DateTimeFormat;
    
    import javax.persistence.*;
    import java.util.Date;
    
    @Table(name = "JPA_PERSONS")
    @Entity
    public class Person { 
        private Integer id ;
        private String lastName ;
        private String email ;
        private Date birth ;
    
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @Id
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        @Column(name = "LAST_NAME")
        public String getLastName() {
            return lastName;
        }
    
        public void setLastName(String lastName) {
            this.lastName = lastName;
        }
    
        public String getEmail() {
            return email;
        }
    
        public void setEmail(String email) {
            this.email = email;
        }
    
        @DateTimeFormat
        public Date getBirth() {
            return birth;
        }
    
        public void setBirth(Date birth) {
            this.birth = birth;
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "id=" + id +
                    ", lastName='" + lastName + '\'' +
                    ", email='" + email + '\'' +
                    ", birth=" + birth +
                    '}';
        }
    }

*  dao层:PersonRepository

package com.ifox.hgx.springdata.dao;
    
    import com.ifox.hgx.springdata.entities.Person;
    import org.springframework.data.repository.Repository;
    
    
    public interface PersonRepository extends Repository<Person,Integer> { 
    
        Person getByLastName(String lastName) ;
    }

*  service层:PersonService

package com.ifox.hgx.springdata.service;
    
    import com.ifox.hgx.springdata.dao.PersonRepository;
    import com.ifox.hgx.springdata.entities.Person;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    @Service
    public class PersonService { 
    
        @Autowired
        private PersonRepository personRepository;
    
        public Person getByLastName(String lastName) {
            return personRepository.getByLastName(lastName);
        }
    
    }

*  测试类:

package com.ifox.hgx.jap.spring;
    
    import com.ifox.hgx.springdata.entities.Person;
    import com.ifox.hgx.springdata.service.PersonService;
    import org.junit.Test;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import javax.sql.DataSource;
    import java.sql.Connection;
    
    public class SpringDataTest { 
    
        private ApplicationContext applicationContext = null;
        private PersonService personService = null;
    
        {
            applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
            personService = applicationContext.getBean(PersonService.class);
        }
    
        @Test
        public void testDataSource() throws Exception {
            DataSource dataSource = applicationContext.getBean(DataSource.class);
            Connection connection = dataSource.getConnection();
            System.out.println(connection);
    
        }
    
        @Test
        public void testPersonFindByLastName() {
            Person person = personService.getByLastName("sjsja") ;
    
            System.out.println(person);
    
        }
    }