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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!
根据hibernate.cfg.xml文件自动建表
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
public class App
{
public static void main(String[] args)
{
// 创建配置管理类对象
Configuration config = new Configuration();
// 加载主配置文件
config.configure();
// 创建工具类对象
SchemaExport export = new SchemaExport(config);
// 建表
// 第一个参数: 是否在控制台打印建表语句
// 第二个参数: 是否执行脚本
export.create(true, true);
}
}
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.h3database.com)
#hibernate.dialect org.hibernate.dialect.H2Dialect
#hibernate.connection.driver_class org.h3.Driver
#hibernate.connection.username sa
#hibernate.connection.password
#hibernate.connection.url jdbc:h3:mem:./build/db/h3/hibernate
#hibernate.connection.url jdbc:h3:testdb/h3test
#hibernate.connection.url jdbc:h3:mem:imdb1
#hibernate.connection.url jdbc:h3:tcp://dbserv:8084/sample;
#hibernate.connection.url jdbc:h3:ssl://secureserv:8085/sample;
#hibernate.connection.url jdbc:h3: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。
联合主键的案例
CompositeKeys.java
package com.rk.hibernate.e_compositekey;
import java.io.Serializable;
//复合主键类
public class CompositeKeys implements Serializable
{
private String username;
private String address;
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
public String getAddress()
{
return address;
}
public void setAddress(String address)
{
this.address = address;
}
}
User.java
package com.rk.hibernate.e_compositekey;
public class User
{
// 名字跟地址,不会重复
private CompositeKeys pkeys;
private int age;
public CompositeKeys getPkeys()
{
return pkeys;
}
public void setPkeys(CompositeKeys pkeys)
{
this.pkeys = pkeys;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
@Override
public String toString()
{
return "User [username=" + pkeys.getUsername() + ", address=" + pkeys.getAddress() + ", age=" + age + "]";
}
}
User.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">
<hibernate-mapping package="com.rk.hibernate.e_compositekey" auto-import="true">
<class name="User" table="t_users">
<composite-id name="pkeys">
<key-property name="username" type="string"></key-property>
<key-property name="address" type="string"></key-property>
</composite-id>
<property name="age" column="age" type="int" ></property>
</class>
</hibernate-mapping>
App.java
package com.rk.hibernate.e_compositekey;
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(User.class).buildSessionFactory();
}
@Test
public void testSave()
{
Session session = null;
Transaction tx = null;
try
{
// 对象
CompositeKeys pkeys = new CompositeKeys();
pkeys.setAddress("火星");
pkeys.setUsername("小明");
User u = new User();
u.setPkeys(pkeys);
u.setAge(20);
// 保存
session = sessionFactory.openSession();
tx = session.beginTransaction();
session.save(u);
System.out.println("执行结束!");
}
catch(Exception e)
{
throw new RuntimeException(e);
}
finally
{
tx.commit();
session.close();
}
}
@Test
public void testQuery()
{
Session session = null;
Transaction tx = null;
try
{
//构建复合主键
CompositeKeys pkeys = new CompositeKeys();
pkeys.setAddress("火星");
pkeys.setUsername("小明");
// 查询
session = sessionFactory.openSession();
tx = session.beginTransaction();
User u = (User) session.get(User.class, pkeys);
System.out.println(u);
System.out.println("执行结束!");
}
catch(Exception e)
{
throw new RuntimeException(e);
}
finally
{
tx.commit();
session.close();
}
}
}
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