在Hibernate中開啟日志

在項目中，如果要排查故障，找出Bug，離不開日志信息。那麼在Hibernate項目中如何開啟日志輸出呢？本文講述如何在Hibernate中開啟日志，以及Hibernate的日志級別。

一、項目開發環境
具體以一個示例項目為例，我們的項目使用了：
1. Maven 3.2.3
http://maven.apache.org/
2. Hibernate 5.0.0.CR1 RELEASE
http://hibernate.org/orm/
3. Eclipse IDE，版本為Luna 4.4.1
http://www.eclipse.org/

二、依賴關系
示例項目使用了以下的開源庫，包括：
1. hibernate-core
ORM持久化的核心庫
2. mysql-connector-java
MySQL的JDBC驅動包
3. slf4j-api
供Hibernate使用的簡單日志Facade
4. slf4j-log4j12
Hibernate使用的日志輸出庫
5. javassist
Hibernate使用的Java字節碼操作庫

Hibernate依賴於抽象日志框架SLF4J，使用SLF4J後，可以選擇多種日志輸出框架。如果項目未綁定任何日志輸出框架，那麼它是沒有任何輸出的。故本示例項目綁定了Log4j作為日志輸出框架。

三、配置Log4j
在項目的類路徑下，創建log4j.properties文件，內容如下：

1. # Root logger option
   
2. log4j.rootLogger=INFO, console
3. log4j.logger.com.ch.demo=INFO, console
4.  
5. # Direct log messages to console
6. log4j.appender.console=org.apache.log4j.ConsoleAppender
7. log4j.appender.console.Target=System.out
8. log4j.appender.console.layout=org.apache.log4j.PatternLayout
9. log4j.appender.console.layout.ConversionPattern=%d{HH:mm}| %p | %F %L | %m%n
10.  
11. # direct messages to file hibernate.log
12. log4j.logger.org.hibernate=DEBUG, hibernate
13. log4j.appender.hibernate=org.apache.log4j.RollingFileAppender
14. log4j.appender.hibernate.File=hibernate.log
15. log4j.appender.hibernate.layout=org.apache.log4j.PatternLayout
16. log4j.appender.hibernate.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %5p %c{1}:%L - %m%n

上面的log4j.properties配置文件中，我們指定所有的Hibernate的具體信息輸出類別為hibernate.log。它用於org.hibernate包。如果只想輸出部分Hibernate類別的信息，那麼需要對指定類別進行配置。

Hibernate主要的類別如下：
1）org.hibernate.SQL
日志輸出所有Hibernate執行的SQL DML語句
2）org.hibernate.type
日志輸出所有的JDBC參數
3）org.hibernate.transaction
日志輸出所有活動相關的事務
4）org.hibernate.jdbc
日志輸出所有的JDBC資源采集
5）org.hibernate.tool.hbm2ddl
日志輸出所有Hibernate執行的SQL DDL語句
6）org.hibernate
日志輸出所有的Hibernate信息

如果指定日志輸出類別為org.hibernate.SQL，那麼將會輸出SQL語句。但是，還有一種更簡單的查看SQL語句的方法，只需簡單地設置show_sql參數為true。

四、Hibernate日志示例

1、創建實體Bean：Order

1. package com.ch.demo.hibernate;
   
2.  
3. import java.util.Date;
4.  
5. public class Order {
6.     private Long orderId;
7.     private String orderNbr;
8.     private Date orderDate;
9.     private String orderDesc;
10.     private Long orderQty;
11.  
12.     public Order() {
13.     }
14.  
15.     public Order(String orderNbr) {
16.         this.orderNbr = orderNbr;
17.     }
18.  
19.     public Long getOrderId() {
20.         return orderId;
21.     }
22.  
23.     private void setOrderId(Long orderId) {
24.         this.orderId = orderId;
25.     }
26.  
27.     public Date getOrderDate() {
28.         return orderDate;
29.     }
30.  
31.     public void setOrderDate(Date orderDate) {
32.         this.orderDate = orderDate;
33.     }
34.  
35.     public String getOrderDesc() {
36.         return orderDesc;
37.     }
38.  
39.     public void setOrderDesc(String orderDesc) {
40.         this.orderDesc = orderDesc;
41.     }
42.  
43.     public Long getOrderQty() {
44.         return orderQty;
45.     }
46.  
47.     public void setOrderQty(Long orderQty) {
48.         this.orderQty = orderQty;
49.     }
50.  
51.     public String toString() {
52.         return "Order: nbr[" + orderNbr + "] date [" + orderDate + "] desc["
53.                 + orderDesc + "] qty[" + orderQty + "]";
54.     }
55. }

2、創建ORM映射文件：orders.hbm.xml

1. <!DOCTYPE hibernate-mapping
   
2. PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
3. "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
4. <hibernate-mapping package="com.ch.demo.hibernate">
5.     <class name="com.ch.demo.hibernate.Order" table="orders">
6.         <id name="orderId" column="order_id">
7.             <generator class="native" />
8.         </id>
9.         <property name="orderNbr" column="order_nbr" type="string" length="30" access="field"/>
10.         <property name="orderDesc" column="order_desc" type="string"
11.             length="60" />
12.         <property name="orderDate" type="timestamp" column="order_date"/>
13.         <property name="orderQty" column="qty" type="long" />
14.     </class>
15. </hibernate-mapping>

3、操作數據庫的示例代碼：HibernateLoggingExample.java

1. package com.ch.demo.hibernate;
   
2.  
3. import java.io.IOException;
4. import java.util.Date;
5. import java.util.List;
6.  
7. import org.hibernate.MappingException;
8. import org.hibernate.Query;
9. import org.hibernate.Session;
10. import org.hibernate.SessionFactory;
11. import org.hibernate.Transaction;
12. import org.hibernate.cfg.Configuration;
13.  
14. public class HibernateLoggingExample {
15.  
16.     public static void main(String[] args) throws MappingException, IOException {
17.         Configuration configuration = new Configuration().configure();
18.         SessionFactory sessionFactory = configuration.buildSessionFactory();
19.         Session session = sessionFactory.getCurrentSession();
20.         Transaction tx = session.getTransaction();
21.         tx.begin();
22.         Query query = session.createQuery("from Order where orderNbr='ORD01'");
23.         List list = query.list();
24.         System.out.println("Orders found: " + list.size());
25.         for(Order order: list) {
26.             session.delete(order);
27.             System.out.println("Deleted " + order);
28.         }
29.         tx.commit();
30.          
31.         session = sessionFactory.getCurrentSession();
32.         tx = session.getTransaction();
33.         tx.begin();
34.         Order order = new Order("ORD01");
35.         order.setOrderDesc("Laptop");
36.         order.setOrderQty(2L);
37.         order.setOrderDate(new Date());
38.         session.save(order);
39.         tx.commit();
40.          
41.         session = sessionFactory.getCurrentSession();
42.         tx = session.getTransaction();
43.         tx.begin();
44.         query = session.createQuery("from Order where orderNbr='ORD01'");
45.         System.out.println("List all orders: " + query.list());
46.         tx.commit();
47.          
48.         sessionFactory.close();
49.     }
50. }

4、日志輸出

1. 19:14| DEBUG | IntegratorServiceImpl.java 46 | Adding Integrator [org.hibernate.cfg.beanvalidation.BeanValidationIntegrator].
   
2. 19:14| DEBUG | IntegratorServiceImpl.java 46 | Adding Integrator [org.hibernate.secure.spi.JaccIntegrator].
3. 19:14| DEBUG | IntegratorServiceImpl.java 46 | Adding Integrator [org.hibernate.cache.internal.CollectionCacheInvalidator].
4. ...
5. 19:14| DEBUG | LocalXmlResourceResolver.java 74 | Recognized legacy hibernate-mapping identifier; attempting to resolve on classpath under org/hibernate/
6. 19:14| DEBUG | MappingBinder.java 53 | Performing JAXB binding of hbm.xml document : Origin(name=orders.hbm.xml,type=RESOURCE)
7. 19:14| DEBUG | BasicTypeRegistry.java 130 | Adding type registration boolean -> org.hibernate.type.BooleanType@55f616cf
8. 19:14| DEBUG | BasicTypeRegistry.java 130 | Adding type registration boolean -> org.hibernate.type.BooleanType@55f616cf
9. 19:14| DEBUG | BasicTypeRegistry.java 130 | Adding type registration java.lang.Boolean -> org.hibernate.type.BooleanType@55f616cf
10. ...
11. 19:14| DEBUG | ErrorCounter.java 95 | throwQueryException() : no errors
12. 19:14| DEBUG | QueryTranslatorImpl.java 246 | HQL: from com.ch.demo.hibernate.Order where orderNbr='ORD01'
13. 19:14| DEBUG | QueryTranslatorImpl.java 247 | SQL: select order0_.order_id as order_id1_0_, order0_.order_nbr as order_nb2_0_, order0_.order_desc as order_de3_0_, order0_.order_date as order_da4_0_, order0_.qty as qty5_0_ from orders order0_ where order0_.order_nbr='ORD01'
14. 19:14| DEBUG | ErrorCounter.java 95 | throwQueryException() : no errors
15. ...
16. 19:14| DEBUG | SqlStatementLogger.java 92 | delete from orders where order_id=?
17. Hibernate: delete from orders where order_id=?
18. ...
19. 19:14| DEBUG | SqlStatementLogger.java 92 | insert into orders (order_nbr, order_desc, order_date, qty) values (?, ?, ?, ?)
20. Hibernate: insert into orders (order_nbr, order_desc, order_date, qty) values (?, ?, ?, ?)

Hibernate+JUnit測試實體類生成數據庫表  http://www.linuxidc.com/Linux/2015-07/120161.htm

Hibernate整體理解 http://www.linuxidc.com/Linux/2014-07/104405.htm

Hibernate的映射機制  http://www.linuxidc.com/Linux/2014-12/110265.htm

Hibernate 的詳細介紹：請點這裡
Hibernate 的下載地址：請點這裡