Grails中的GORM是一个基于Hibernate开发出来的崭新ORM框架，其优点就是无需任何配置。但早期的GORM有个不太方便的地方，就是如果想Grails自动创建的表名和字段名是由自己制定的，那么我们就不得不使用hibernate的映射文件，这样就又用回hibernate了。幸好Grails1.0提供了让我们DIY表和字段的DSL，使我们可以彻底摆脱XML配置文件的阴影。
遵循“Groovy轻松入门系列”的一贯做法，下面还是以一个实例来说明GORM DSL到底是怎么回事，它会带给我们多大的便利。
1，执行‘grails create-app GormDslDemo’，创建一个名为GormDslDemo的Grails项目
D:\_DEV\grails_apps>grails create-app GormDslDemo
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\CreateApp.groovy
Environment set to development
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\src
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\src\java
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\src\groovy
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\controllers
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\services
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\domain
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\taglib
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\utils
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\views
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\views\layouts
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\i18n
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\conf
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\test
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\test\unit
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\test\integration
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\scripts
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\web-app
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\web-app\js
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\web-app\css
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\web-app\images
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\web-app\META-INF
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\lib
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\conf\spring
[mkdir] Created dir: D:\_DEV\grails_apps\GormDslDemo\grails-app\conf\hibernate
[propertyfile] Creating new property file: D:\_DEV\grails_apps\GormDslDemo\application.properties
[copy] Copying 2 files to D:\_DEV\grails_apps\GormDslDemo
[copy] Copying 2 files to D:\_DEV\grails_apps\GormDslDemo\web-app\WEB-INF
[copy] Copying 5 files to D:\_DEV\grails_apps\GormDslDemo\web-app\WEB-INF\tld
[copy] Copying 87 files to D:\_DEV\grails_apps\GormDslDemo\web-app
[copy] Copying 17 files to D:\_DEV\grails_apps\GormDslDemo\grails-app
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo
[propertyfile] Updating property file: D:\_DEV\grails_apps\GormDslDemo\application.properties
Created Grails Application at D:\_DEV\grails_apps/GormDslDemo
D:\_DEV\grails_apps>
2，将数据库JDBC驱动jar文件放到lib目录下，比如我使用的数据库是MySQL，那么JDBC驱动jar文件就是mysql-connector-java-5.1.5-bin.jar
3，配置数据源，将grails-app\conf\DataSource.groovy修改为（注意：假设您也是用MySQL，记得将用户名和密码改为自己的）
dataSource {
pooled = false
//driverClassName = "org.hsqldb.jdbcDriver"
driverClassName = "com.mysql.jdbc.Driver"
//username = "sa"
username = "root"
//password = ""
password = "123"
}
hibernate {
cache.use_second_level_cache=true
cache.use_query_cache=true
cache.provider_class='org.hibernate.cache.EhCacheProvider'
}
// environment specific settings
environments {
development {
dataSource {
dbCreate = "create-drop" // one of 'create', 'create-drop','update'
//url = "jdbc:hsqldb:mem:devDB"
url = "jdbc:mysql://localhost:3306/gorm_dsl_demo?createDatabaseIfNotExist=true"
}
}
test {
dataSource {
dbCreate = "update"
url = "jdbc:hsqldb:mem:testDb"
}
}
production {
dataSource {
dbCreate = "update"
url = "jdbc:hsqldb:file:prodDb;shutdown=true"
}
}
}
4，创建domain class，在本例中，我们创建两个domain class，沿用经典的Author和Book
创建Author
D:\_DEV\grails_apps\GormDslDemo>grails create-domain-class Author
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps\GormDslDemo
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\CreateDomainClass.groovy
Environment set to development
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo\grails-app\domain
Created for Author
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo\test\integration
Created Tests for Author
D:\_DEV\grails_apps\GormDslDemo>
创建Book
D:\_DEV\grails_apps\GormDslDemo>grails create-domain-class Book
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps\GormDslDemo
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\CreateDomainClass.groovy
Environment set to development
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo\grails-app\domain
Created for Book
[copy] Copying 1 file to D:\_DEV\grails_apps\GormDslDemo\test\integration
Created Tests for Book
D:\_DEV\grails_apps\GormDslDemo>
5，修改grails-app\domain目录下的Author.groovy和Book.groovy：Author.groovy
class Author {
String name
static hasMany = [books: Book]
static mapping = {
table 'AUTHOR'
columns {
name column:'AUTHOR_NAME'
}
id generator:'increment', column:'AUTHOR_ID_PK'
version false
}
}
Book.groovy
class Book {
String name
Float price
Author author
static mapping = {
table 'BOOK'
columns {
name column:'BOOK_NAME'
price column:'BOOK_PRICE'
author column:'AUTHOR_ID_FK'
}
id generator:'increment', column:'BOOK_ID_PK'
version false
}
}
对上面的mapping这个closure稍微解释一下，以Book中的mapping为例，
static mapping = {
table 'BOOK' // 为Book类生成的表名为BOOK，您可以将它改为其他名字，比如BOOK_TABLE等
columns {
name column:'BOOK_NAME' // 表中与name属性相对应的字段名为BOOK_NAME
price column:'BOOK_PRICE' // 类似地，表中与price属性相对应的字段名为BOOK_PRICE
author column:'AUTHOR_ID_FK' // 表中与author属性相对应的字段名为AUTHOR_ID_FK，该字段是一个外键
}
id generator:'increment', column:'BOOK_ID_PK' // 指定id生成的策略为increment以及其对应的字段名为BOOK_ID_PK
version false // 不让Grails自动生成version字段，该字段用来支持乐观锁，一般不建议将其去除，这里仅仅是为了演示
}6, 执行'grails generate-all Author'和'grails generate-all Book'命令生成与Author和Book相关的CRUD的所有代码和页面。
D:\_DEV\grails_apps\GormDslDemo>grails generate-all Author
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps\GormDslDemo
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\GenerateAll.groovy
Environment set to development
[mkdir] Created dir: C:\Documents and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo\classes
[groovyc] Compiling 8 source files to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\Gorm
DslDemo\classes
[mkdir] Created dir: C:\Documents and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo\resourc
es\grails-app\i18n
[native2ascii] Converting 10 files from D:\_DEV\grails_apps\GormDslDemo\grails-app\i18n to C:\Docume
nts and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo\resources\grails-app\i18n
[copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo\cl
asses
[copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo\re
sources
[copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\GormDslDemo
[0] spring.GrailsWebApplicationContext Refreshing org.codehaus.groovy.grails.commons.spring.GrailsWe
bApplicationContext@f4a376: display name [org.codehaus.groovy.grails.commons.spring.GrailsWebApplica
tionContext@f4a376]; startup date [Fri Apr 04 00:00:55 CST 2008]; root of context hierarchy
[0] spring.GrailsWebApplicationContext Bean factory for application context [org.codehaus.groovy.gra
ils.commons.spring.GrailsWebApplicationContext@f4a376]: org.springframework.beans.factory.support.De
faultListableBeanFactory@101ac1c
Generating views for domain class Author 
Generating controller for domain class Author
Finished generation for domain class Author D:\_DEV\grails_apps\GormDslDemo>grails generate-all Book
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps\GormDslDemo
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\GenerateAll.groovy
Environment set to development
[groovyc] Compiling 2 source files to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\Gorm
DslDemo\classes
[0] spring.GrailsWebApplicationContext Refreshing org.codehaus.groovy.grails.commons.spring.GrailsWe
bApplicationContext@15863e4: display name [org.codehaus.groovy.grails.commons.spring.GrailsWebApplic
ationContext@15863e4]; startup date [Fri Apr 04 00:03:29 CST 2008]; root of context hierarchy
[15] spring.GrailsWebApplicationContext Bean factory for application context [org.codehaus.groovy.gr
ails.commons.spring.GrailsWebApplicationContext@15863e4]: org.springframework.beans.factory.support.
DefaultListableBeanFactory@f4ca49
Generating views for domain class Book
Generating controller for domain class Book
Finished generation for domain class Book
D:\_DEV\grails_apps\GormDslDemo> 7，启动完MySQL数据库之后，执行'grails run-app'命令，启动web服务器。
D:\_DEV\grails_apps\GormDslDemo>grails run-app
Welcome to Grails 1.0.2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0.2
Base Directory: D:\_DEV\grails_apps\GormDslDemo
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0.2\scripts\RunApp.groovy
Environment set to development
[groovyc] Compiling 2 source files to C:\Documents and Settings\Daniel\.grails\1.0.2\projects\Gorm
DslDemo\classes
Running Grails application..
2008-04-04 00:06:07.861::INFO: Logging to STDERR via org.mortbay.log.StdErrLog
2008-04-04 00:06:07.095::INFO: jetty-6.1.4
2008-04-04 00:06:08.454::INFO: No Transaction manager found - if your webapp requires one, please c
onfigure one.
2008-04-04 00:06:08.329:/GormDslDemo:INFO: Set web app root system property: 'GormDslDemo' = [D:\_D
EV\grails_apps\GormDslDemo\web-app\]
2008-04-04 00:06:08.345:/GormDslDemo:INFO: Initializing Log4J from [file:C:\Documents and Settings\
Daniel/.grails/1.0.2/projects/GormDslDemo/resources/log4j.properties]
2008-04-04 00:06:08.376:/GormDslDemo:INFO: Initializing Spring root WebApplicationContext
[0] spring.GrailsWebApplicationContext Refreshing org.codehaus.groovy.grails.commons.spring.GrailsWe
bApplicationContext@c393a1: display name [org.codehaus.groovy.grails.commons.spring.GrailsWebApplica
tionContext@c393a1]; startup date [Fri Apr 04 00:06:12 CST 2008]; parent: org.springframework.web.co
ntext.support.XmlWebApplicationContext@bd3b2d
[0] spring.GrailsWebApplicationContext Bean factory for application context [org.codehaus.groovy.gra
ils.commons.spring.GrailsWebApplicationContext@c393a1]: org.springframework.beans.factory.support.De
faultListableBeanFactory@144569b
2008-04-04 00:06:19.620:/GormDslDemo:INFO: Initializing Spring FrameworkServlet 'grails'
2008-04-04 00:06:20.151::INFO: Started SelectChannelConnector@0.0.0.0:8080
Server running. Browse to http://localhost:8080/GormDslDemo
8，打开浏览器，访问：http://localhost:8080/GormDslDemo ，看一下自己的劳动成果。
9，查看MySQL中，Grails自动帮您生成的表：
AUTHOR表
CREATE TABLE `author` (
`AUTHOR_ID_PK` bigint(20) NOT NULL,
`AUTHOR_NAME` varchar(255) NOT NULL,
PRIMARY KEY (`AUTHOR_ID_PK`)
)
BOOK表
CREATE TABLE `book` (
`BOOK_ID_PK` bigint(20) NOT NULL,
`AUTHOR_ID_FK` bigint(20) NOT NULL,
`BOOK_NAME` varchar(255) NOT NULL,
`BOOK_PRICE` float NOT NULL,
PRIMARY KEY (`BOOK_ID_PK`),
KEY `FK1F32E99AB78860` (`AUTHOR_ID_FK`),
CONSTRAINT `FK1F32E99AB78860` FOREIGN KEY (`AUTHOR_ID_FK`) REFERENCES `author` (`AUTHOR_ID_PK`)
)
看过这篇文章后，或多或少给了您一些如何方便地处理遗留数据库的启发了吧 :)
附：
朝花夕拾——Groovy & Grails
posted on 2008-04-04 00:53
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Groovy & Grails