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

1、下载 Hibernate5：官网下载，百度云下载。

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

秒客网

java框架之Hibernate(1)-简介及初使用

简介

使用

导包

代码

抽取工具类

配置C3p0连接池

配置log4j

相关文章