3.Hibernate入门笔记

Hibernate入门指南笔记

1. 首先下载Hibernate包

Hibernate5.0.7

2. 在MySQL中建立数据库和表

CREATE DATABASE myblog;
USE myblog;
CREATE TABLE IF NOT EXISTS cust_customer(
  cust_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT '用户id',
  cust_name VARCHAR(32) NOT NULL COMMENT '客户名称(公司名称)',
  cust_source VARCHAR(32) DEFAULT NULL COMMENT '客户信息来源',
  cust_industry VARCHAR(32) DEFAULT NULL COMMENT '客户所属行业',
  cust_level VARCHAR(32) DEFAULT NULL COMMENT '客户级别',
  cust_phone VARCHAR(64) DEFAULT NULL COMMENT '固定电话',
  cust_mobile VARCHAR(14) DEFAULT NULL COMMENT '移动电话'
);
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3. 导入数据库驱动包与Hibernate包以及日志记录包

3.1 导入Hibernate包以下

3.2 导入MySQL数据库链接驱动包

mysql-connector-java-5.1.43-bin.jar

3.3 导入日志记录包

在工程目录下面新建一个lib目录将所须要的包拷贝到lib文件夹下

选中全部文件将包添加到项目中

若是添加成功，在项目文件目录下面会有一个Libraries包含所添加的外部库

4.在工程的src下建立一个实体，对应于数据库中的cust_customer表

package com.whong;
public class cust_customer {
	private long cust_id;
	private String cust_name;
	private String cust_source;
	private String cust_industry;
	private String cust_level;
	private String cust_phone;
	private String cust_mobile;
	
	public long getCust_id() {
		return cust_id;
	}
	public void setCust_id(long cust_id) {
		this.cust_id = cust_id;
	}
	public String getCust_name() {
		return cust_name;
	}
	public void setCust_name(String cust_name) {
		this.cust_name = cust_name;
	}
	public String getCust_source() {
		return cust_source;
	}
	public void setCust_source(String cust_source) {
		this.cust_source = cust_source;
	}
	public String getCust_industry() {
		return cust_industry;
	}
	public void setCust_industry(String cust_industry) {
		this.cust_industry = cust_industry;
	}
	public String getCust_level() {
		return cust_level;
	}
	public void setCust_level(String cust_level) {
		this.cust_level = cust_level;
	}
	public String getCust_phone() {
		return cust_phone;
	}
	public void setCust_phone(String cust_phone) {
		this.cust_phone = cust_phone;
	}
	public String getCust_mobile() {
		return cust_mobile;
	}
	public void setCust_mobile(String cust_mobile) {
		this.cust_mobile = cust_mobile;
	}
}
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5.建立映射文件

映射文件是将刚才的实体cust_customer映射到数据库中的 由于安装了hibernate的插件，因此在这里能够直接选择建立hbm文件，不须要手动去配置

在这里有多是这样一个包的，可是对应的不该该是这个包，须要对应于那个类cust_customer，所以须要点击Add class添加cust_customer类到这里来

对应的hbm文件以下

<?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 Feb 28, 2018 2:40:14 PM by Hibernate Tools 3.5.0.Final -->
<hibernate-mapping>
    <class name="com.whong.cust_customer" table="CUST_CUSTOMER">
        <id name="cust_id" type="long">
            <column name="CUST_ID" />
            <generator class="assigned" />
        </id>
        <property name="cust_name" type="java.lang.String">
            <column name="CUST_NAME" />
        </property>
        <property name="cust_source" type="java.lang.String">
            <column name="CUST_SOURCE" />
        </property>
        <property name="cust_industry" type="java.lang.String">
            <column name="CUST_INDUSTRY" />
        </property>
        <property name="cust_level" type="java.lang.String">
            <column name="CUST_LEVEL" />
        </property>
        <property name="cust_phone" type="java.lang.String">
            <column name="CUST_PHONE" />
        </property>
        <property name="cust_mobile" type="java.lang.String">
            <column name="CUST_MOBILE" />
        </property>
    </class>
</hibernate-mapping>
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6.建立Hibernate的核心配置文件

在第五步骤中的映射文件反应的是持久化类和数据库表的映射信息，而Hibernate的配置文件则主要是用来配置数据库链接以及Hibernate运行时所须要的各个属性的值，在src文件夹下建立cfg类型的文件

在cfg配置界面这里很关键须要注意

点击Get values from Connection

新建一个链接配置文件

选择mysql在name这里能够标注一下以示区分链接不一样的数据库 在这里选择数据库的驱动

点击这个车轮

Name/Type选择5.1

Jar List须要移除这个驱动，点击Add JAR/Zip 选择刚才添加进去的sql数据库链接驱动

返回到Connection Profile这里，修改database为myblog所对应的数据库，同时须要注意的是，在url那里须要添加 ?usessl=true 完整的url为 jdbc:mysql://localhost:3306/myblog?usessl=true

7.编写一个测试代码

测试代码以下所示

package com.testPackage;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import com.whong.cust_customer;

public class testHibernate {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Configuration configuration = new Configuration().configure();
		SessionFactory sessionFactory = configuration.buildSessionFactory();
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		cust_customer cust_customer = new cust_customer();
		cust_customer.setCust_name("伟鸿");
		cust_customer.setCust_phone("18*******969");
		session.save(cust_customer);
		transaction.commit();
		session.close();
	}
}
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8.试运行

若是这个时候试运行会报有以下的错误

log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" org.hibernate.MappingException: Unknown entity: com.whong.cust_customer
	at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:781)
	at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1520)
	at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:100)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
	at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
	at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
	at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:679)
	at org.hibernate.internal.SessionImpl.save(SessionImpl.java:671)
	at org.hibernate.internal.SessionImpl.save(SessionImpl.java:666)
	at com.testPackage.testHibernate.main(testHibernate.java:21)
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8.1解决方案

这里最主要的问题就是log日志文件的问题 解决方式是须要添加一个有关日志的配置文件，具体能够看一下这个连接的文章log4j WARN 和 SLF4J WARN 解决办法 在src目录下添加log4j.properties配置文件

hadoop.root.logger=DEBUG, console
log4j.rootLogger=INFO, console
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.target=System.out
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss} %p %c{2}: %m%n
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8.2实体映射错误解决方式

再次运行会报以下的错误

Exception in thread "main" org.hibernate.MappingException: Unknown entity: com.whong.cust_customer
	at org.hibernate.internal.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:781)
	at org.hibernate.internal.SessionImpl.getEntityPersister(SessionImpl.java:1520)
	at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:100)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
	at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
	at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
	at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
	at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:679)
	at org.hibernate.internal.SessionImpl.save(SessionImpl.java:671)
	at org.hibernate.internal.SessionImpl.save(SessionImpl.java:666)
	at com.testPackage.testHibernate.main(testHibernate.java:21)
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这个问题时由于核心配置文件cfg和实体映射文件hbm之间没有对应起来，因此找不到那个cust_customer实体 解决方式以下 拷贝hbm文件的路径

在cfg配置文件下添加以下语句 <mapping resource="/LearnHibernate/src/com/whong/cust_customer.hbm.xml"/> 可是这个地方须要去掉src前面的路径 所以正确的路径是 <mapping resource="com/whong/cust_customer.hbm.xml"/>

再次运行的到正确的结果 并打印以下的一些日志记录

18/02/28 16:21:05 INFO hibernate.Version: HHH000412: Hibernate Core {5.0.7.Final}
18/02/28 16:21:05 INFO cfg.Environment: HHH000206: hibernate.properties not found
18/02/28 16:21:05 INFO cfg.Environment: HHH000021: Bytecode provider name : javassist
18/02/28 16:21:05 INFO common.Version: HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
18/02/28 16:21:05 WARN orm.deprecation: HHH90000012: Recognized obsolete hibernate namespace http://hibernate.sourceforge.net/hibernate-mapping. Use namespace http://www.hibernate.org/dtd/hibernate-mapping instead.  Support for obsolete DTD/XSD namespaces may be removed at any time.
18/02/28 16:21:06 WARN orm.connections: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
18/02/28 16:21:06 INFO orm.connections: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/myblog?useSSL=true]
18/02/28 16:21:06 INFO orm.connections: HHH10001001: Connection properties: {user=root, password=****}
18/02/28 16:21:06 INFO orm.connections: HHH10001003: Autocommit mode: false
18/02/28 16:21:06 INFO internal.DriverManagerConnectionProviderImpl: HHH000115: Hibernate connection pool size: 20 (min=1)
18/02/28 16:21:07 INFO dialect.Dialect: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
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再数据库中查询cust_customer表也是能够查询到这一条记录的 至此hibernate的入门配置笔记完毕

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