》#千鋒逆戰(zhàn)#

如果數(shù)據(jù)庫(kù)中有表粗卜，我們可以逆向工程，如果數(shù)據(jù)庫(kù)中沒(méi)有表纳击，但是我們有實(shí)體類(lèi)续扔，我們可以使用正向工程

pom.xml

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.28</version>
        </dependency>
        <!--
            添加spring-data-jpa的依賴(lài)
        -->
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.11.0.RELEASE</version>
        </dependency>
        <!--
            spring-data-jpa依賴(lài)于hibernate-entitymanager
        -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.2.10.Final</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>4.3.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.6</version>
        </dependency>
    </dependencies>

db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/jpa?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedStatements=TRUE
user=root
pass=123456

spring-jpa.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:property-placeholder location="classpath:db.properties"/>

    <context:component-scan base-package="com.qfedu.service"/>
    <context:component-scan base-package="com.qfedu.dao"/>

    <bean id="ds" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="url" value="${url}"/>
        <property name="driverClassName" value="${driver}"/>
        <property name="username" value="${user}"/>
        <property name="password" value="${pass}"/>
    </bean>

    <!--
        配置 HibernateJpaVendorAdapter，用來(lái)分別設(shè)置數(shù)據(jù)庫(kù)的方言和是否顯示sql語(yǔ)句
    -->
    <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" id="adapter">
        <!--<property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect"/>-->
        <property name="databasePlatform" value="org.hibernate.dialect.MySQL57InnoDBDialect"/>
        <property name="showSql" value="true"/>
    </bean>

    <!--
        配置EntityManagerFactoryBean
    -->
    <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="emf">
        <property name="dataSource" ref="ds"/>
        <property name="packagesToScan" value="com.qfedu.entity"/>
        <property name="jpaVendorAdapter" ref="adapter"/>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.format_sql">true</prop>
                <!--
                   使用hibernate.hbm2ddl.auto屬性來(lái)根據(jù)需要?jiǎng)討B(tài)創(chuàng)建數(shù)據(jù)庫(kù)的表結(jié)構(gòu)
                   create：表示啟動(dòng)的時(shí)候先drop焕数，再create
                   create-drop: 也表示創(chuàng)建纱昧，只不過(guò)再系統(tǒng)關(guān)閉前執(zhí)行一下drop
                   update: 這個(gè)操作啟動(dòng)的時(shí)候會(huì)去檢查schema是否一致，如果不一致會(huì)做scheme更新
                   validate: 啟動(dòng)時(shí)驗(yàn)證現(xiàn)有schema與你配置的hibernate是否一致堡赔，如果不一致就拋出異常识脆，并不做更新
               -->
                <prop key="hibernate.hbm2ddl.auto">validate</prop>
            </props>
        </property>
    </bean>

    <!--
        配置jpa的事務(wù)管理器
    -->
    <bean class="org.springframework.orm.jpa.JpaTransactionManager" id="jtx">
        <property name="entityManagerFactory" ref="emf"/>
    </bean>
    <!--配置事務(wù)驅(qū)動(dòng)-->
    <tx:annotation-driven proxy-target-class="false" transaction-manager="jtx"/>
    <jpa:repositories base-package="com.qfedu.dao" entity-manager-factory-ref="emf" transaction-manager-ref="jtx"/>

</beans>

entity

package com.qfedu.entity;

import lombok.Data;

import javax.persistence.*;

@Data
@Entity
@Table(name = "tbl_emp")
public class Emp {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "eid")
    private int eid;
    /**
     * Column注解的各個(gè)屬性值說(shuō)明：
     * name用來(lái)指定該屬性所對(duì)應(yīng)的列名，默認(rèn)與屬性名一致
     * unique為true代表該屬性生成的字段唯一，默認(rèn)不唯一
     * nullable為false不允許為空灼捂，默認(rèn)運(yùn)行為空
     * length可以給字段指定長(zhǎng)度离例，默認(rèn)為255
     */
    @Column(name = "first_name",nullable = false,unique = true,length = 20)
    private String firstName;
    @Column(name = "last_name")
    private String lastName;
    private double Salary;
}

dao

package com.qfedu.dao;

import com.qfedu.entity.Emp;
import org.hibernate.boot.model.source.spi.JpaCallbackSource;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import java.io.Serializable;
@Repository
public interface IEmpDao extends JpaRepository<Emp, Serializable> {
}

service

package com.qfedu.service;

import com.qfedu.entity.Emp;

public interface IEmpService {
    void saveEmp(Emp emp);
}

service.impl

package com.qfedu.service.impl;

import com.qfedu.dao.IEmpDao;
import com.qfedu.entity.Emp;
import com.qfedu.service.IEmpService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class EmpServiceImpl implements IEmpService {
    @Resource
    private IEmpDao empDao;

    @Override
    public void saveEmp(Emp emp) {
        empDao.saveAndFlush(emp);
    }
}

test

package com.qfedu.test;

import com.qfedu.entity.Emp;
import com.qfedu.service.IEmpService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:spring-jpa.xml")
public class TestEmp {
    @Resource
    private IEmpService empService;
    @Test
    public void saveEmp() {
        Emp emp = new Emp();
        emp.setFirstName("豬");
        emp.setLastName("八戒");
        emp.setSalary(200000);
        empService.saveEmp(emp);
    }
}