java框架之Hibernate(1)-简介及初使用
简介
hibernate 是一个开源 ORM ( Object / Relationship Mipping ) 框架，它是对象关联关系映射的持久层框架，它对 JDBC 做了轻量级的封装，而我们 java 程序员可以使用面向对象的思想来操纵数据库。
使用
导包
2、解压，项目中导入解压后 '/lib/required' 下所有 jar 包，然后导入上面百度云链接中日志支持jar包。
代码
1、编写一个 JavaBean 作为映射模型，如：
package com.zze.bean;
public class 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;
}
}
com.zze.bean.Customer
2、在该模型同目录下创建该模型的映射文件：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!--
class : 配置类和表的映射
name : 类的全路径
table : 对应表名
如果类名和表名一致，表名可省略不写
-->
<class name="com.zze.bean.Customer" table="customer">
<!--
id : 配置属性和主键列的映射
name : 属性名
column ： 列名
-->
<id name="cust_id" column="cust_id">
<!--
generator : 配置主键的生成策略
class : 配置主键生成策略类型，可选如下几个值：
increment：由 Hibernate 自动以递增的方式生成标识符，每次增量 1
identity：由底层数据库生成标识符，前提条件是底层数据库支持自动增长字段类型（DB2,MYSQL）
uuid:用 128 位的 UUID 算法生成字符串类型标识符
assigned:由java程序负责生成标识符，让应用程序在save()之前为对象分配一个标识符。
-->
<generator class="native"/>
</id>
<!--
property : 配置属性和列的映射
name : 属性名
column : 列名
legth : 对应列的长度
如果属性名和列名一致，列名可以省略不写
-->
<property name="cust_name" column="cust_name" length="32"/>
<property name="cust_source" column="cust_source" length="32"/>
<property name="cust_industry" column="cust_industry" length="100"/>
<property name="cust_level" column="cust_level" length="100"/>
<property name="cust_phone" column="cust_phone" length="30"/>
<property name="cust_mobile" column="cust_mobile" length="30"/>
</class>
</hibernate-mapping>
com/zze/bean/Customer.hbm.xml
3、在 src 根目录下新建 Hibernate 全局配置文件：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!--=======================必须配置start========================-->
<!--数据库驱动-->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!--数据库连接url-->
<property name="hibernate.connection.url">jdbc:mysql://192.168.202.132:3306/test</property>
<!--数据库用户名-->
<property name="hibernate.connection.username">root</property>
<!--数据库密码-->
<property name="hibernate.connection.password">root</property>
<!--数据库方言-->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<!--=======================必须配置end========================-->
<!--=======================可选配置start========================-->
<!--显示 sql-->
<property name="hibernate.show_sql">true</property>
<!--格式化 sql-->
<property name="hibernate.format_sql">true</property>
<!--
是否自动创建数据库表，它主要有一下几个值：
none : 不使用 hibernate 自动建表
create : 如果数据库中已经有表，删除原有表重新创建；如果没有表，那就新建表。
create-drop : 如果数据库中已经有表，删除原有表重新创建,执行完操作后又删除该表；如果没有表，那就新建表，执行完操作后删除该表。
update (常用) : 如果数据库中已经有表，更新表结构，使用原有表；如果没有表，创建新表。
validate (常用) : 如果没有表，不会创建表，会校验 JavaBean 和表结构的映射关系，使用数据库中原有的结构。
-->
<property name="hibernate.hbm2ddl.auto">update</property>
<!--引入映射文件-->
<mapping resource="com/zze/bean/Customer.hbm.xml"></mapping>
<!--=======================可选配置end========================-->
</session-factory>
</hibernate-configuration>
hibernate.cfg.xml
4、编写测试类测试新增：
package com.zze.test;
import com.zze.bean.Customer;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.Test;
import java.util.List;
public class HibernateTest {
@Test
public void test1() {
// 加载核心配置文件
Configuration configuration = new Configuration().configure();
// 创建一个 sessionFactory 对象
SessionFactory sessionFactory = configuration.buildSessionFactory();
// 获取 session
Session session = sessionFactory.openSession();
// 开启事务
Transaction transaction = session.beginTransaction();
Customer customer = new Customer();
customer.setCust_name("张三");
// 新增 customer
session.save(customer);
// 提交事务
transaction.commit();
// 释放 session
session.close();
// 释放 sessionFactory
sessionFactory.close();
/*
执行之后会发现 Hibernate 在对应数据库中新建了 customer 表，并新建了一条 cust_name 为 ‘张三’ 的数据。
mysql> select * from customer;
+---------+-----------+-------------+---------------+------------+------------+-------------+
| cust_id | cust_name | cust_source | cust_industry | cust_level | cust_phone | cust_mobile |
+---------+-----------+-------------+---------------+------------+------------+-------------+
| 1 | 张三 | NULL | NULL | NULL | NULL | NULL |
+---------+-----------+-------------+---------------+------------+------------+-------------+
row in set (0.00 sec)
*/
}
}
com.zze.test.HibernateTest
映射文件的 XML 约束可在 'hibernate-core.jar' 下的 'hibernate-mapping-3.0.dtd' 中找到。
全局配置文件的 XML 约束可在 'hibernate-core.jar' 下的 'hibernate-configuration-3.0.dtd' 中找到。
全局配置文件的名称固定为 'hibernate.cfg.xml'，查看源码：
public static final String DEFAULT_CFG_RESOURCE_NAME = "hibernate.cfg.xml";
public Configuration configure() throws HibernateException {
return configure( StandardServiceRegistryBuilder.DEFAULT_CFG_RESOURCE_NAME );
}
org.hibernate.cfg.Configuration.configure
全局配置文件中的可配置参数可以在解压后 Hibernate 的 zip 包目录 'project/etc/hibernate.properties' 文件中找到，如下：
# # Hibernate, Relational Persistence for Idiomatic Java # # License: GNU Lesser General Public License (LGPL), version 2.1 or later. # See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>. # ###################### ### Query Language ### ###################### ## define query language constants / function names hibernate.query.substitutions yes 'Y', no 'N' ## select the classic query parser #hibernate.query.factory_class org.hibernate.hql.internal.classic.ClassicQueryTranslatorFactory ################# ### Platforms ### ################# ## JNDI Datasource #hibernate.connection.datasource jdbc/test #hibernate.connection.username db2 #hibernate.connection.password db2 ## HypersonicSQL hibernate.dialect org.hibernate.dialect.HSQLDialect hibernate.connection.driver_class org.hsqldb.jdbcDriver hibernate.connection.username sa hibernate.connection.password hibernate.connection.url jdbc:hsqldb:./build/db/hsqldb/hibernate #hibernate.connection.url jdbc:hsqldb:hsql://localhost #hibernate.connection.url jdbc:hsqldb:test ## H2 (www.h2database.com) #hibernate.dialect org.hibernate.dialect.H2Dialect #hibernate.connection.driver_class org.h2.Driver #hibernate.connection.username sa #hibernate.connection.password #hibernate.connection.url jdbc:h2:mem:./build/db/h2/hibernate #hibernate.connection.url jdbc:h2:testdb/h2test #hibernate.connection.url jdbc:h2:mem:imdb1 #hibernate.connection.url jdbc:h2:tcp://dbserv:8084/sample; #hibernate.connection.url jdbc:h2:ssl://secureserv:8085/sample; #hibernate.connection.url jdbc:h2:ssl://secureserv/testdb;cipher=AES ## MySQL #hibernate.dialect org.hibernate.dialect.MySQLDialect #hibernate.dialect org.hibernate.dialect.MySQLInnoDBDialect #hibernate.dialect org.hibernate.dialect.MySQLMyISAMDialect #hibernate.connection.driver_class com.mysql.jdbc.Driver #hibernate.connection.url jdbc:mysql:///test #hibernate.connection.username gavin #hibernate.connection.password ## Oracle #hibernate.dialect org.hibernate.dialect.Oracle8iDialect #hibernate.dialect org.hibernate.dialect.Oracle9iDialect #hibernate.dialect org.hibernate.dialect.Oracle10gDialect #hibernate.connection.driver_class oracle.jdbc.driver.OracleDriver #hibernate.connection.username ora #hibernate.connection.password ora #hibernate.connection.url jdbc:oracle:thin:@localhost:1521:orcl #hibernate.connection.url jdbc:oracle:thin:@localhost:1522:XE ## PostgreSQL #hibernate.dialect org.hibernate.dialect.PostgreSQLDialect #hibernate.connection.driver_class org.postgresql.Driver #hibernate.connection.url jdbc:postgresql:template1 #hibernate.connection.username pg #hibernate.connection.password ## DB2 #hibernate.dialect org.hibernate.dialect.DB2Dialect #hibernate.connection.driver_class com.ibm.db2.jcc.DB2Driver #hibernate.connection.driver_class COM.ibm.db2.jdbc.app.DB2Driver #hibernate.connection.url jdbc:db2://localhost:50000/somename #hibernate.connection.url jdbc:db2:somename #hibernate.connection.username db2 #hibernate.connection.password db2 ## TimesTen #hibernate.dialect org.hibernate.dialect.TimesTenDialect #hibernate.connection.driver_class com.timesten.jdbc.TimesTenDriver #hibernate.connection.url jdbc:timesten:direct:test #hibernate.connection.username #hibernate.connection.password ## DB2/400 #hibernate.dialect org.hibernate.dialect.DB2400Dialect #hibernate.connection.username user #hibernate.connection.password password ## Native driver #hibernate.connection.driver_class COM.ibm.db2.jdbc.app.DB2Driver #hibernate.connection.url jdbc:db2://systemname ## Toolbox driver #hibernate.connection.driver_class com.ibm.as400.access.AS400JDBCDriver #hibernate.connection.url jdbc:as400://systemname ## Derby (not supported!) #hibernate.dialect org.hibernate.dialect.DerbyDialect #hibernate.connection.driver_class org.apache.derby.jdbc.EmbeddedDriver #hibernate.connection.username #hibernate.connection.password #hibernate.connection.url jdbc:derby:build/db/derby/hibernate;create=true ## Sybase #hibernate.dialect org.hibernate.dialect.SybaseDialect #hibernate.connection.driver_class com.sybase.jdbc2.jdbc.SybDriver #hibernate.connection.username sa #hibernate.connection.password sasasa #hibernate.connection.url jdbc:sybase:Tds:co3061835-a:5000/tempdb ## Mckoi SQL #hibernate.dialect org.hibernate.dialect.MckoiDialect #hibernate.connection.driver_class com.mckoi.JDBCDriver #hibernate.connection.url jdbc:mckoi:/// #hibernate.connection.url jdbc:mckoi:local://C:/mckoi1.0.3/db.conf #hibernate.connection.username admin #hibernate.connection.password nimda ## SAP DB #hibernate.dialect org.hibernate.dialect.SAPDBDialect #hibernate.connection.driver_class com.sap.dbtech.jdbc.DriverSapDB #hibernate.connection.url jdbc:sapdb://localhost/TST #hibernate.connection.username TEST #hibernate.connection.password TEST #hibernate.query.substitutions yes 'Y', no 'N' ## MS SQL Server #hibernate.dialect org.hibernate.dialect.SQLServerDialect #hibernate.connection.username sa #hibernate.connection.password sa ## JSQL Driver #hibernate.connection.driver_class com.jnetdirect.jsql.JSQLDriver #hibernate.connection.url jdbc:JSQLConnect://1E1/test ## JTURBO Driver #hibernate.connection.driver_class com.newatlanta.jturbo.driver.Driver #hibernate.connection.url jdbc:JTurbo://1E1:1433/test ## WebLogic Driver #hibernate.connection.driver_class weblogic.jdbc.mssqlserver4.Driver #hibernate.connection.url jdbc:weblogic:mssqlserver4:1E1:1433 ## Microsoft Driver (not recommended!) #hibernate.connection.driver_class com.microsoft.jdbc.sqlserver.SQLServerDriver #hibernate.connection.url jdbc:microsoft:sqlserver://1E1;DatabaseName=test;SelectMethod=cursor ## The New Microsoft Driver #hibernate.connection.driver_class com.microsoft.sqlserver.jdbc.SQLServerDriver #hibernate.connection.url jdbc:sqlserver://localhost ## jTDS (since version 0.9) #hibernate.connection.driver_class net.sourceforge.jtds.jdbc.Driver #hibernate.connection.url jdbc:jtds:sqlserver://1E1/test ## Interbase #hibernate.dialect org.hibernate.dialect.InterbaseDialect #hibernate.connection.username sysdba #hibernate.connection.password masterkey ## DO NOT specify hibernate.connection.sqlDialect ## InterClient #hibernate.connection.driver_class interbase.interclient.Driver #hibernate.connection.url jdbc:interbase://localhost:3060/C:/firebird/test.gdb ## Pure Java #hibernate.connection.driver_class org.firebirdsql.jdbc.FBDriver #hibernate.connection.url jdbc:firebirdsql:localhost/3050:/firebird/test.gdb ## Pointbase #hibernate.dialect org.hibernate.dialect.PointbaseDialect #hibernate.connection.driver_class com.pointbase.jdbc.jdbcUniversalDriver #hibernate.connection.url jdbc:pointbase:embedded:sample #hibernate.connection.username PBPUBLIC #hibernate.connection.password PBPUBLIC ## Ingres ## older versions (before Ingress 2006) #hibernate.dialect org.hibernate.dialect.IngresDialect #hibernate.connection.driver_class ca.edbc.jdbc.EdbcDriver #hibernate.connection.url jdbc:edbc://localhost:II7/database #hibernate.connection.username user #hibernate.connection.password password ## Ingres 2006 or later #hibernate.dialect org.hibernate.dialect.IngresDialect #hibernate.connection.driver_class com.ingres.jdbc.IngresDriver #hibernate.connection.url jdbc:ingres://localhost:II7/database;CURSOR=READONLY;auto=multi #hibernate.connection.username user #hibernate.connection.password password ## Mimer SQL #hibernate.dialect org.hibernate.dialect.MimerSQLDialect #hibernate.connection.driver_class com.mimer.jdbc.Driver #hibernate.connection.url jdbc:mimer:multi1 #hibernate.connection.username hibernate #hibernate.connection.password hibernate ## InterSystems Cache #hibernate.dialect org.hibernate.dialect.Cache71Dialect #hibernate.connection.driver_class com.intersys.jdbc.CacheDriver #hibernate.connection.username _SYSTEM #hibernate.connection.password SYS #hibernate.connection.url jdbc:Cache://127.0.0.1:1972/HIBERNATE ################################# ### Hibernate Connection Pool ### ################################# hibernate.connection.pool_size 1 ########################### ### C3P0 Connection Pool### ########################### #hibernate.c3p0.max_size 2 #hibernate.c3p0.min_size 2 #hibernate.c3p0.timeout 5000 #hibernate.c3p0.max_statements 100 #hibernate.c3p0.idle_test_period 3000 #hibernate.c3p0.acquire_increment 2 #hibernate.c3p0.validate false ############################## ### Proxool Connection Pool### ############################## ## Properties for external configuration of Proxool hibernate.proxool.pool_alias pool1 ## Only need one of the following #hibernate.proxool.existing_pool true #hibernate.proxool.xml proxool.xml #hibernate.proxool.properties proxool.properties ################################# ### Plugin ConnectionProvider ### ################################# ## use a custom ConnectionProvider (if not set, Hibernate will choose a built-in ConnectionProvider using hueristics) #hibernate.connection.provider_class org.hibernate.connection.DriverManagerConnectionProvider #hibernate.connection.provider_class org.hibernate.connection.DatasourceConnectionProvider #hibernate.connection.provider_class org.hibernate.connection.C3P0ConnectionProvider #hibernate.connection.provider_class org.hibernate.connection.ProxoolConnectionProvider ####################### ### Transaction API ### ####################### ## Enable automatic flush during the JTA beforeCompletion() callback ## (This setting is relevant with or without the Transaction API) #hibernate.transaction.flush_before_completion ## Enable automatic session close at the end of transaction ## (This setting is relevant with or without the Transaction API) #hibernate.transaction.auto_close_session ## the Transaction API abstracts application code from the underlying JTA or JDBC transactions #hibernate.transaction.factory_class org.hibernate.transaction.JTATransactionFactory #hibernate.transaction.factory_class org.hibernate.transaction.JDBCTransactionFactory ## to use JTATransactionFactory, Hibernate must be able to locate the UserTransaction in JNDI ## default is java:comp/UserTransaction ## you do NOT need this setting if you specify hibernate.transaction.manager_lookup_class #jta.UserTransaction jta/usertransaction #jta.UserTransaction javax.transaction.UserTransaction #jta.UserTransaction UserTransaction ## to use the second-level cache with JTA, Hibernate must be able to obtain the JTA TransactionManager #hibernate.transaction.manager_lookup_class org.hibernate.transaction.JBossTransactionManagerLookup #hibernate.transaction.manager_lookup_class org.hibernate.transaction.WeblogicTransactionManagerLookup #hibernate.transaction.manager_lookup_class org.hibernate.transaction.WebSphereTransactionManagerLookup #hibernate.transaction.manager_lookup_class org.hibernate.transaction.OrionTransactionManagerLookup #hibernate.transaction.manager_lookup_class org.hibernate.transaction.ResinTransactionManagerLookup ############################## ### Miscellaneous Settings ### ############################## ## print all generated SQL to the console #hibernate.show_sql true ## format SQL in log and console hibernate.format_sql true ## add comments to the generated SQL #hibernate.use_sql_comments true ## generate statistics #hibernate.generate_statistics true ## auto schema export #hibernate.hbm2ddl.auto create-drop #hibernate.hbm2ddl.auto create #hibernate.hbm2ddl.auto update #hibernate.hbm2ddl.auto validate ## specify a default schema and catalog for unqualified tablenames #hibernate.default_schema test #hibernate.default_catalog test ## enable ordering of SQL UPDATEs by primary key #hibernate.order_updates true ## set the maximum depth of the outer join fetch tree hibernate.max_fetch_depth 1 ## set the default batch size for batch fetching #hibernate.default_batch_fetch_size 8 ## rollback generated identifier values of deleted entities to default values #hibernate.use_identifer_rollback true ## enable bytecode reflection optimizer (disabled by default) #hibernate.bytecode.use_reflection_optimizer true ##################### ### JDBC Settings ### ##################### ## specify a JDBC isolation level #hibernate.connection.isolation 4 ## enable JDBC autocommit (not recommended!) #hibernate.connection.autocommit true ## set the JDBC fetch size #hibernate.jdbc.fetch_size 25 ## set the maximum JDBC 2 batch size (a nonzero value enables batching) #hibernate.jdbc.batch_size 5 #hibernate.jdbc.batch_size 0 ## enable batch updates even for versioned data hibernate.jdbc.batch_versioned_data true ## enable use of JDBC 2 scrollable ResultSets (specifying a Dialect will cause Hibernate to use a sensible default) #hibernate.jdbc.use_scrollable_resultset true ## use streams when writing binary types to / from JDBC hibernate.jdbc.use_streams_for_binary true ## use JDBC 3 PreparedStatement.getGeneratedKeys() to get the identifier of an inserted row #hibernate.jdbc.use_get_generated_keys false ## choose a custom JDBC batcher # hibernate.jdbc.factory_class ## enable JDBC result set column alias caching ## (minor performance enhancement for broken JDBC drivers) # hibernate.jdbc.wrap_result_sets ## choose a custom SQL exception converter #hibernate.jdbc.sql_exception_converter ########################## ### Second-level Cache ### ########################## ## optimize cache for minimal "puts" instead of minimal "gets" (good for clustered cache) #hibernate.cache.use_minimal_puts true ## set a prefix for cache region names hibernate.cache.region_prefix hibernate.test ## disable the second-level cache #hibernate.cache.use_second_level_cache false ## enable the query cache #hibernate.cache.use_query_cache true ## store the second-level cache entries in a more human-friendly format #hibernate.cache.use_structured_entries true ## choose a cache implementation #hibernate.cache.region.factory_class org.hibernate.cache.infinispan.InfinispanRegionFactory #hibernate.cache.region.factory_class org.hibernate.cache.infinispan.JndiInfinispanRegionFactory #hibernate.cache.region.factory_class org.hibernate.cache.internal.EhCacheRegionFactory #hibernate.cache.region.factory_class org.hibernate.cache.internal.SingletonEhCacheRegionFactory hibernate.cache.region.factory_class org.hibernate.cache.internal.NoCachingRegionFactory ## choose a custom query cache implementation #hibernate.cache.query_cache_factory ############ ### JNDI ### ############ ## specify a JNDI name for the SessionFactory #hibernate.session_factory_name hibernate/session_factory ## Hibernate uses JNDI to bind a name to a SessionFactory and to look up the JTA UserTransaction; ## if hibernate.jndi.* are not specified, Hibernate will use the default InitialContext() which ## is the best approach in an application server #file system #hibernate.jndi.class com.sun.jndi.fscontext.RefFSContextFactory #hibernate.jndi.url file:/ #WebSphere #hibernate.jndi.class com.ibm.websphere.naming.WsnInitialContextFactory #hibernate.jndi.url iiop://localhost:900/
hibernate.properties
核心配置文件还可以以 properties 文件形式存在，只是使用 properties 形式核心配置文件时需要手动加载映射文件，如下：
hibernate.connection.driver_class=com.mysql.jdbc.Driver hibernate.connection.url=jdbc:mysql://192.168.202.132:3306/test hibernate.connection.username=root hibernate.connection.password=root hibernate.dialect=org.hibernate.dialect.MySQLDialect hibernate.hbm2ddl.auto=update
hibernate.properties
Configuration configuration = new Configuration();
configuration.addResource("com/zze/bean/Customer.hbm.xml");
SessionFactory sessionFactory = configuration.buildSessionFactory();
test
其它常用 API :
package com.zze.test;
import com.zze.bean.Customer;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.Test;
import java.util.List;
public class HibernateTest {
@Test
public void test2() {
/**
* 查询所有
*/
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
List from_customer = session.createQuery("from Customer").list();
for (Object o : from_customer) {
System.out.println(o);
}
session.close();
sessionFactory.close();
/*
Customer{cust_id=1, cust_name='张三'}
*/
}
@Test
public void test3() {
/**
* 根据主键查询
*/
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
Customer customer = session.get(Customer.class, 1L);
System.out.println(customer);
session.close();
sessionFactory.close();
/*
Customer{cust_id=1, cust_name='张三'}
*/
}
@Test
public void test4() {
/**
* 修改
*/
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
Customer customer = session.get(Customer.class, 1L);
customer.setCust_name("王德发");
session.update(customer);
transaction.commit();
session.close();
sessionFactory.close();
}
@Test
public void test5() {
/**
* 删除
*/
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
Customer customer = new Customer();
customer.setCust_id(1L);
session.delete(customer);
transaction.commit();
session.close();
sessionFactory.close();
}
@Test
public void test6() {
/**
* 新增或修改
* 目标实例存在主键时修改 不存在则新增
*/
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
Customer customer = new Customer();
customer.setCust_name("赵六");
session.saveOrUpdate(customer);
transaction.commit();
session.close();
sessionFactory.close();
}
}
com.zze.test.HibernateTest
load 的延迟加载（懒加载）机制：
@Test
public void testLoad() {
Session session1 = HibernateUtil.openSession();
Customer customer1 = session1.get(Customer.class, 1l); // 立即发出 sql 语句
System.out.println(customer1); // null
session1.close();
Session session2 = HibernateUtil.openSession();
Customer customer2 = session2.load(Customer.class, 1l); // 不发出 sql 语句
System.out.println(customer2); // throw org.hibernate.ObjectNotFoundException
session2.close();
/*
get 和 load 的不同：
使用 get 时会立即从数据库中查询数据。
使用 load 时会返回一个代理对象，当使用这个代理对象时才会即时从数据库查询数据。
*/
}
test
抽取工具类
package com.zze.util;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
public static final Configuration cfg;
public static final SessionFactory sf;
static {
cfg = new Configuration().configure();
sf = cfg.buildSessionFactory();
}
public static Session openSession(){
return sf.openSession();
}
}
HibernateUtil.java
配置C3p0连接池
1、导入 hibernate zip 包解压后目录 'lib/optional/c3p0' 下所有包。
2、在全局配置文件中配置如下属性：
<!--=======================配置C3P0连接池start=======================--> <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property> <!--在连接池中可用的数据库连接的最少数目 --> <property name="c3p0.min_size">5</property> <!--在连接池中所有数据库连接的最大数目 --> <property name="c3p0.max_size">20</property> <!--设定数据库连接的过期时间,以秒为单位,如果连接池中的某个数据库连接处于空闲状态的时间超过了timeout时间,就会从连接池中清除 --> <property name="c3p0.timeout">120</property> <!--每3000秒检查所有连接池中的空闲连接 以秒为单位--> <property name="c3p0.idle_test_period">3000</property> <!--=======================配置C3P0连接池end=======================-->
配置log4j
### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.err
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
### direct messages to file mylog.log ###
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=c\:mylog.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
### set log levels - for more verbose logging change 'info' to 'debug' ###
# error warn info debug trace
log4j.rootLogger= info, stdout
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