3.Hibernate入門筆記

時間 2019-12-04

標籤 3.hibernate hibernate 入門筆記欄目 Hibernate 简体版

原文原文鏈接

Hibernate入門指南筆記html

1. 首先下載Hibernate包

Hibernate5.0.7java

2. 在MySQL中建立數據庫和表

CREATE DATABASE myblog;
USE myblog;
CREATE TABLE IF NOT EXISTS cust_customer(
  cust_id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT '用戶id',
  cust_name VARCHAR(32) NOT NULL COMMENT '客戶名稱(公司名稱)',
  cust_source VARCHAR(32) DEFAULT NULL COMMENT '客戶信息來源',
  cust_industry VARCHAR(32) DEFAULT NULL COMMENT '客戶所屬行業',
  cust_level VARCHAR(32) DEFAULT NULL COMMENT '客戶級別',
  cust_phone VARCHAR(64) DEFAULT NULL COMMENT '固定電話',
  cust_mobile VARCHAR(14) DEFAULT NULL COMMENT '移動電話'
);
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3. 導入數據庫驅動包與Hibernate包以及日誌記錄包

3.1 導入Hibernate包以下

3.2 導入MySQL數據庫鏈接驅動包

mysql-connector-java-5.1.43-bin.jarmysql

3.3 導入日誌記錄包

在工程目錄下面新建一個lib目錄將所須要的包拷貝到lib文件夾下 git

選中全部文件將包添加到項目中

若是添加成功，在項目文件目錄下面會有一個Libraries包含所添加的外部庫

4.在工程的src下建立一個實體，對應於數據庫中的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

映射文件是將剛纔的實體cust_customer映射到數據庫中的由於安裝了hibernate的插件，因此在這裏能夠直接選擇建立hbm文件，不須要手動去配置 github

在這裏有多是這樣一個包的，可是對應的不該該是這個包，須要對應於那個類cust_customer，所以須要點擊Add class添加cust_customer類到這裏來

對應的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

在第五步驟中的映射文件反應的是持久化類和數據庫表的映射信息，而Hibernate的配置文件則主要是用來配置數據庫鏈接以及Hibernate運行時所須要的各個屬性的值，在src文件夾下建立cfg類型的文件 sql

在cfg配置界面這裏很關鍵須要注意

點擊Get values from Connection

新建一個鏈接配置文件

選擇mysql在name這裏能夠標註一下以示區分鏈接不一樣的數據庫在這裏選擇數據庫的驅動

點擊這個車輪

Name/Type選擇5.1

Jar List須要移除這個驅動，點擊Add JAR/Zip 選擇剛纔添加進去的sql數據庫鏈接驅動

返回到Connection Profile這裏，修改database爲myblog所對應的數據庫，同時須要注意的是，在url那裏須要添加 ?usessl=true 完整的url爲 jdbc:mysql://localhost:3306/myblog?usessl=true

7.編寫一個測試代碼

測試代碼以下所示數據庫

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("偉鴻");
		cust_customer.setCust_phone("18*******969");
		session.save(cust_customer);
		transaction.commit();
		session.close();
	}
}
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8.試運行

若是這個時候試運行會報有以下的錯誤apache

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解決方案

這裏最主要的問題就是log日誌文件的問題解決方式是須要添加一個有關日誌的配置文件，具體能夠看一下這個連接的文章log4j WARN 和 SLF4J WARN 解決辦法在src目錄下添加log4j.properties配置文件bash

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實體映射錯誤解決方式

再次運行會報以下的錯誤session

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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這個問題時由於核心配置文件cfg和實體映射文件hbm之間沒有對應起來，因此找不到那個cust_customer實體解決方式以下拷貝hbm文件的路徑

在cfg配置文件下添加以下語句 <mapping resource="/LearnHibernate/src/com/whong/cust_customer.hbm.xml"/> 可是這個地方須要去掉src前面的路徑所以正確的路徑是 <mapping resource="com/whong/cust_customer.hbm.xml"/>

再次運行的到正確的結果並打印以下的一些日誌記錄

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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再數據庫中查詢cust_customer表也是能夠查詢到這一條記錄的至此hibernate的入門配置筆記完畢

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