SS6.2_Hibernate_Hibernate_IdStrategyAnnotation 主键生成策略uuid Annotation注解的配置方式

字符串字段sid主键的生成策略使用的是uuid,全球唯一编码主键可以在分布式系统中使用；

我们接下来要创建的项目结构：



创建学生实体：
package net.nw.vo;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import org.hibernate.annotations.GenericGenerator;
@Entity  //@Entity表示Student这个类在数据库当中将被映射为一张表，表名称就叫做Student
public class Student {
private String sid;
private String sname;
//@Id表示属性对应的私有属性sid是数据库表中的主键

//@GeneratedValue表示主键的生成方式;generator="stu_id"表示使用自定义生成器的名称

//@GenericGenerator表示自定义一个hibernate主键生成器;name="stu_id"表示自定义生成器的名称;strategy="uuid"指定生成策略生成主键

@Id  

@GeneratedValue(generator="stu_id")  

@GenericGenerator(name="stu_id",strategy="uuid")
public String getSid() {
return sid;
}
public void setSid(String sid) {
this.sid = sid;
}
public String getSname() {
return sname;
}
public void setSname(String sname) {
this.sname = sname;
}
}

创建数据库连接配置文件和注册对象 - 关系实体类映射文件：
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>
    <session-factory>
  <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
 <property name="connection.url">jdbc:mysql://localhost:3306/testdb</property>
 <property name="connection.username">root</property>
 <property name="connection.password">123456</property>
 <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
 <property name="show_sql">true</property>
 <property name="hbm2ddl.auto">update</property>
 <property name="current_session_context_class">thread</property>
 <mapping class="net.nw.vo.Student"
/>
    </session-factory>
</hibernate-configuration>
创建日志配置文件log4j.properties：
### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
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 hibernate.log ###
#log4j.appender.file=org.apache.log4j.FileAppender
#log4j.appender.file.File=hibernate.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' ###

log4j.rootLogger=warn, stdout

#log4j.logger.org.hibernate=info
#log4j.logger.org.hibernate=debug

### log HQL query parser activity
#log4j.logger.org.hibernate.hql.ast.AST=debug

### log just the SQL
log4j.logger.org.hibernate.SQL=debug

### log JDBC bind parameters ###
log4j.logger.org.hibernate.type=info
#log4j.logger.org.hibernate.type=debug

### log schema export/update ###
log4j.logger.org.hibernate.tool.hbm2ddl=debug

### log HQL parse trees
#log4j.logger.org.hibernate.hql=debug

### log cache activity ###
#log4j.logger.org.hibernate.cache=debug

### log transaction activity
log4j.logger.org.hibernate.transaction=debug

### log JDBC resource acquisition
#log4j.logger.org.hibernate.jdbc=debug

### enable the following line if you want to track down connection ###
### leakages when using DriverManagerConnectionProvider ###
#log4j.logger.org.hibernate.connection.DriverManagerConnectionProvider=trace
创建单元测试文件：
package net.nw.vo;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.AnnotationConfiguration;
import junit.framework.TestCase;
public class TestStudent extends TestCase {
private static SessionFactory sessionFactory ;
@Override
protected void setUp() throws Exception {
System.out.println("setUp()...");
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
@Override
protected void tearDown() throws Exception {
System.out.println("tearDown()...");
sessionFactory.close();
}
public void testSave(){
Session session = sessionFactory.getCurrentSession();
Transaction tx = session.beginTransaction();
try{
Student s = new Student();
s.setSname("zhangsan");  // 主键没赋值显然希望主键自动生成
session.save(s);
tx.commit();
}catch(Exception ex){
tx.rollback();
ex.printStackTrace();
}
}

}
导入单元测试jar包：
项目上右键单击 ------》Build Path ------》Configure Build Path ... ------》Add Library ... ------》JUnit ------》JUnit library version: JUnit 4  ------》OK

导入mysql-connector-java-5.1.40-bin.jar的jar包:
项目上右键单击 ------》Build Path ------》Configure Build Path ... ------》Add External JARS ... ------》/root/mysql-connector-java-5.1.40-bin/mysql-connector-java-5.1.40-bin.jar ------》OK

运行单元测试方法testSave()，注意控制台输出的创建student表结构的SQL脚本：
运行单元测试之前必需手动地把testdb数据库中的学生表删掉：drop table student;
用鼠标一直展开到TestStudent单元测试类内部的所有方法这一层 ------》右键单击testSave() void ------》Run As ------》Junit Test
添加第1条记录zhangsan时，控制台会输出如下信息：
Student s = new Student();
s.setSname("zhangsan");  // 主键没赋值显然希望主键自动生成
session.save(s);
tx.commit();

setUp()...

11:23:33,042  INFO TransactionFactoryFactory:59 - Using default transaction strategy (direct JDBC transactions)

11:23:33,044  INFO TransactionManagerLookupFactory:80 - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended)

11:23:33,227  INFO SchemaUpdate:155 - Running hbm2ddl schema update

11:23:33,227  INFO SchemaUpdate:167 - fetching database metadata

11:23:33,229  INFO SchemaUpdate:179 - updating schema

11:23:33,233  INFO DatabaseMetadata:119 - table not found: Student

11:23:33,234  INFO DatabaseMetadata:119 - table not found: Student

11:23:33,234 DEBUG SchemaUpdate:203 -
create table Student (sid varchar(255) not null, sname varchar(255), primary key (sid))

11:23:33,240  INFO SchemaUpdate:217 - schema update complete

11:23:33,293 DEBUG JDBCTransaction:82 - begin

11:23:33,293 DEBUG JDBCTransaction:87 - current autocommit status: false

11:23:33,299 DEBUG JDBCTransaction:134 - commit

11:23:33,303 DEBUG SQL:111 - insert into Student (sname, sid) values (?, ?)

Hibernate: insert into Student (sname, sid) values (?, ?)

11:23:33,326 DEBUG JDBCTransaction:147 - committed JDBC Connection

tearDown()...

添加第2条记录lisi时，控制台会输出如下信息：
Student s = new Student();
s.setSname("lisi");  // 主键没赋值显然希望主键自动生成
session.save(s);
tx.commit();

setUp()...

11:28:56,652  INFO TransactionFactoryFactory:59 - Using default transaction strategy (direct JDBC transactions)

11:28:56,654  INFO TransactionManagerLookupFactory:80 - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended)

11:28:56,808  INFO SchemaUpdate:155 - Running hbm2ddl schema update

11:28:56,808  INFO SchemaUpdate:167 - fetching database metadata

11:28:56,809  INFO SchemaUpdate:179 - updating schema

11:28:56,824  INFO TableMetadata:65 - table found: testdb.student

11:28:56,824  INFO TableMetadata:66 - columns: [sid, sname]

11:28:56,825  INFO TableMetadata:68 - foreign keys: []

11:28:56,825  INFO TableMetadata:69 - indexes: [primary]

11:28:56,825  INFO SchemaUpdate:217 - schema update complete

11:28:56,879 DEBUG JDBCTransaction:82 - begin

11:28:56,879 DEBUG JDBCTransaction:87 - current autocommit status: false

11:28:56,886 DEBUG JDBCTransaction:134 - commit

11:28:56,903 DEBUG SQL:111 - insert into Student (sname, sid) values (?, ?)

Hibernate: insert into Student (sname, sid) values (?, ?)

11:28:56,916 DEBUG JDBCTransaction:147 - committed JDBC Connection

tearDown()...



MySQL-connector-Java-5.1.40.zip包：http://download.csdn.NET/detail/zhengzizhi/9747510

SS6.2_Hibernate_Hibernate_IdStrategyAnnotation.zip源码下载地址：http://download.csdn.net/detail/zhengzizhi/9750737



添加单元测试方法 testSchemaExpert()，该方法自动创建数据库表

package net.nw.vo;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.AnnotationConfiguration;

import org.hibernate.tool.hbm2ddl.SchemaExport;

import junit.framework.TestCase;

public class TestStudent extends TestCase {
private static SessionFactory sessionFactory ;
@Override
protected void setUp() throws Exception {
System.out.println("setUp()...");
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
@Override
protected void tearDown() throws Exception {
System.out.println("tearDown()...");
sessionFactory.close();
}
public void testSave(){
Session session = sessionFactory.getCurrentSession();
Transaction tx = session.beginTransaction();
try{
Student s = new Student();
s.setSname("lisi");
session.save(s);
tx.commit();

}catch(Exception ex){
tx.rollback();
ex.printStackTrace();
}
}
public void testSchemaExpert(){
 SchemaExport se = new SchemaExport(new AnnotationConfiguration().configure());
 se.create(true,true);
}

}

只运行单元测试方法testSchemaExpert()控制台输出如下信息，注意输出的红色字体标识的SQL语句

setUp()...

13:20:02,325  INFO TransactionFactoryFactory:59 - Using default transaction strategy (direct JDBC transactions)

13:20:02,327  INFO TransactionManagerLookupFactory:80 - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended)

13:20:02,555  INFO SchemaUpdate:155 - Running hbm2ddl schema update

13:20:02,555  INFO SchemaUpdate:167 - fetching database metadata

13:20:02,556  INFO SchemaUpdate:179 - updating schema

13:20:02,559  INFO DatabaseMetadata:119 - table not found: Student

13:20:02,560  INFO DatabaseMetadata:119 - table not found: Student

13:20:02,560 DEBUG SchemaUpdate:203 - create table Student (sid varchar(255) not null, sname varchar(255), primary key (sid))

13:20:02,568  INFO SchemaUpdate:217 - schema update complete

13:20:02,580  INFO SchemaExport:226 - Running hbm2ddl schema export

13:20:02,581 DEBUG SchemaExport:242 - import file not found: /import.sql

13:20:02,581  INFO SchemaExport:251 - exporting generated schema to database

drop table if exists Student

13:20:02,586 DEBUG SchemaExport:377 - drop table if exists Student

create table Student (sid varchar(255) not null, sname varchar(255), primary key (sid))

13:20:02,596 DEBUG SchemaExport:377 - create table Student (sid varchar(255) not null, sname varchar(255), primary key (sid))

13:20:02,603  INFO SchemaExport:268 - schema export complete

tearDown()...