1、Hibernate.cfg.xml 主配置
Hibernate.cfg.xml是主配置文件，其中配置大体分为3部分：数据库连接信息、其他参数、映射信息！
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <!-- 通常，一个session-factory节点代表一个数据库 --> <session-factory> <!-- 1. 数据库连接配置 --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql:///test</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <!-- 数据库方言配置， hibernate在运行的时候，会根据不同的方言生成符合当前数据库语法的sql --> <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property> <!-- 2. 其他相关配置 --> <!-- 2.1 显示hibernate在运行时候执行的sql语句 --> <property name="hibernate.show_sql">false</property> <!-- 2.2 格式化sql --> <property name="hibernate.format_sql">true</property> <!-- 2.3 自动建表 --> <property name="hibernate.hbm2ddl.auto">update</property> <!-- 3. 加载所有映射 --> <mapping resource="com/rk/hibernate/a_hello/Employee.hbm.xml"/> </session-factory> </hibernate-configuration>
1.1、数据库连接参数配置
## 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
1.2、自动建表
#hibernate.hbm2ddl.auto create-drop 每次在创建sessionFactory时候执行创建表；当调用sesisonFactory的close方法的时候，删除表！ #hibernate.hbm2ddl.auto create 每次都重新建表； 如果表已经存在就先删除再创建 #hibernate.hbm2ddl.auto update 如果表不存在就创建； 表存在就不创建； #hibernate.hbm2ddl.auto validate (生成环境时候) 执行验证： 当映射文件的内容与数据库表结构不一样的时候就报错！
1.3、常用配置参考文件
常用配置参考文件：hibernate-distribution-3.6.0.Final\project\etc\hibernate.properties
###################### ### 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.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 chache 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.provider_class org.hibernate.cache.EhCacheProvider #hibernate.cache.provider_class org.hibernate.cache.EmptyCacheProvider hibernate.cache.provider_class org.hibernate.cache.HashtableCacheProvider #hibernate.cache.provider_class org.hibernate.cache.TreeCacheProvider #hibernate.cache.provider_class org.hibernate.cache.OSCacheProvider #hibernate.cache.provider_class org.hibernate.cache.SwarmCacheProvider ## 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/
2、映射配置
1、普通字段类型
2、主键映射
a)单列主键映射
b)多列作为主键映射
Employee.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- 映射文件: 映射一个实体类对象； 描述一个对象最终实现可以直接保存对象数据到数据库中。 -->
<!--
package: 要映射的对象所在的包(可选,如果不指定,此文件所有的类都要指定全路径)
auto-import 默认为true， 在写hql的时候自动导入包名
如果指定为false, 在写hql的时候必须要写上类的全名；
如：session.createQuery("from com.rk.hibernate.d_hbm_config.Employee").list();
-->
<hibernate-mapping package="com.rk.hibernate.d_hbm_config" auto-import="true">
<!--
class 映射某一个对象的(一般情况，一个对象写一个映射文件，即一个class节点)
name 指定要映射的对象的类型
table 指定对象对应的表；
如果没有指定表名，默认与对象名称一样
-->
<class name="Employee" table="employee">
<!-- 主键，映射 -->
<id name="empId" column="id">
<!--
主键的生成策略
identity 自增长(mysql,db2)
sequence 自增长(序列)， oracle中自增长是以序列方法实现
native 自增长【会根据底层数据库自增长的方式选择identity或sequence】
如果是mysql数据库, 采用的自增长方式是identity
如果是oracle数据库， 使用sequence序列的方式实现自增长
increment 自增长(会有并发访问的问题，一般在服务器集群环境使用会存在问题。)
assigned 指定主键生成策略为手动指定主键的值
uuid 指定uuid随机生成的唯一的值
foreign (外键的方式， one-to-one讲)
-->
<generator class="uuid"/>
</id>
<!--
普通字段映射
property
name 指定对象的属性名称
column 指定对象属性对应的表的字段名称，如果不写默认与对象属性一致。
length 指定字符的长度, 默认为255（只适用于字符串类型）
type 指定映射表的字段的类型，如果不指定会匹配属性的类型
java类型： 必须写全名 java.lang.String
hibernate类型： 直接写类型，都是小写 string
-->
<property name="empName" column="empName" type="string" length="20"></property>
<property name="workDate" column="workDate" type="java.util.Date"></property>
<!-- 如果列名称为数据库关键字，需要用反引号或改列名。 -->
<property name="desc" column="`desc`" type="java.lang.String"></property>
</class>
</hibernate-mapping>
Employee.java
package com.rk.hibernate.d_hbm_config;
import java.util.Date;
public class Employee
{
private String empId;
private String empName;
private Date workDate;
private String desc;
public String getEmpId()
{
return empId;
}
public void setEmpId(String empId)
{
this.empId = empId;
}
public String getEmpName()
{
return empName;
}
public void setEmpName(String empName)
{
this.empName = empName;
}
public Date getWorkDate()
{
return workDate;
}
public void setWorkDate(Date workDate)
{
this.workDate = workDate;
}
public String getDesc()
{
return desc;
}
public void setDesc(String desc)
{
this.desc = desc;
}
@Override
public String toString()
{
return "Employee [empId=" + empId + ", empName=" + empName + ", workDate=" + workDate + ", desc=" + desc + "]";
}
}
App.java
package com.rk.hibernate.d_hbm_config;
import java.util.Date;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.Test;
public class App
{
private static SessionFactory sessionFactory;
static
{
sessionFactory = new Configuration()
.configure()
.addClass(Employee.class) //会自动加载映射文件：Employee.hbm.xml。这样，在hibernate.cfg.xml中就不用添加映射了
.buildSessionFactory();
}
@Test
public void testSave()
{
Session session = null;
Transaction tx = null;
try
{
Employee emp = new Employee();
emp.setEmpName("Tom");
emp.setWorkDate(new Date());
emp.setDesc("这里是描述");
session = sessionFactory.openSession();
tx = session.beginTransaction();
session.save(emp);
System.out.println("执行结束！");
}
catch(Exception e)
{
throw new RuntimeException(e);
}
finally
{
tx.commit();
session.close();
}
}
}
3、数据库问题
（1）一个表能否有多个主键？ 不能。
（2）为什么要设置主键？ 数据库存储的数据都是有效的，必须保持唯一。
（3）为什么把id作为主键？因为表中通常找不到合适的列作为唯一列即主键，所以为了方法用id列，因为id是数据库系统维护可以保证唯一，所以就把这列作为主键!
（4）联合/复合主键。如果找不到合适的列作为主键，出来用id列以外，我们一般用联合主键，即多列的值作为一个主键，从而确保记录的唯一性。
时间： 2024-08-09 06:33:28