First they ignore you
then they ridicule you
then they fight you
then you win
    -- Mahatma Gandhi
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在学习任何东西之前,最重要的是培养兴趣,Groovy世界最耀眼的技术之一--Grails相信大家早已耳闻,我将通过Grails实战系列文章向您展现Grails的迷人风采,使您感受到Grails的魅力,以至疯狂地爱上Grails,并坠入Groovy的爱河。学Groovy,Grails与学Java一样,在实战之前需要搭建开发环境,您可以在 Groovy轻松入门--搭建Groovy开发环境 学习到如何搭建Groovy环境,之后我会讲一下如何搭建Grails环境,然后手把手地写个Demo程序告终,我还会抽空写篇“Groovy轻松入门--Grails实战之进阶篇”

一,搭建Grails环境
0,下载Grails( http://dist.codehaus.org/grails/grails-bin-1.0.zip,请留意朝花夕拾——Groovy & Grails中的“最新版本”提示)并解压到自己指定位置(我的位置是D:\D\MY_DEV\grails)
1,设置环境变量GRAILS_HOME(注意大写),过程与“设置环境变量GROOVY_HOME”相似
2,将%GRAILS_HOME%\bin添加到环境变量path中,过程与“将GROOVY_HOME目录下的bin追加到环境变量path中”相似
(如果只想进行Grails开发,可以不设GROOVY_HOME)

二,创建Grails Demo程序
3,打开“命令行”,选择当前目录(我的为D:\Temp\grails_apps),在黑底白字的窗口中输入“grails create-app demo”,不包括双引号“”,在您的屏幕中可以看到类似下面的输出结果:

D:\_DEV\grails_apps>grails create-app demo

Welcome to Grails 1.0 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0

Base Directory: D:\_DEV\grails_apps
Environment set to development
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0\scripts\CreateApp.groovy
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\src
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\src\java
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\src\groovy
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\controllers
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\services
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\domain
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\taglib
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\utils
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\views
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\views\layouts
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\i18n
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\conf
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\test
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\test\unit
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\test\integration
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\scripts
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\js
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\css
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\images
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\WEB-INF\classes
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\META-INF
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\lib
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\conf\spring
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\grails-app\conf\hibernate
[propertyfile] Creating new property file: D:\_DEV\grails_apps\demo\application.properties
     [copy] Copying 2 files to D:\_DEV\grails_apps\demo
     [copy] Copying 2 files to D:\_DEV\grails_apps\demo\web-app\WEB-INF
     [copy] Copying 5 files to D:\_DEV\grails_apps\demo\web-app\WEB-INF\tld
     [copy] Copying 87 files to D:\_DEV\grails_apps\demo\web-app
     [copy] Copying 17 files to D:\_DEV\grails_apps\demo\grails-app
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo
[propertyfile] Updating property file: D:\_DEV\grails_apps\demo\application.properties
Created Grails Application at D:\_DEV\grails_apps/demo
D:\_DEV\grails_apps>

通过“grails create-app”这个命令,Grails自动帮我们创建了开发所需的工程环境。其实您现在就已经拥有了一个可运行的Web应用程序,
然后进入demo目录(“cd demo”),输入“grails run-app”,回车,启动这个‘五脏俱全’的程序雏形,打开浏览器,输入 http://localhost:8080/demo ,回车,看到了吧 :) 让我们继续吧,请停止这个程序(Ctrl + C)

4,在“命令行”中输入“cd demo”,回车,以进入demo目录,然后再输入“grails create-domain-class User”创建domain class即类似于pojo的pogo,它对应MVC中的Model,不过由Grails自动创建的pogo是空的,需要自己添加属性,约束(constraints)等。输出结果如下所示:

D:\_DEV\grails_apps\demo>grails create-domain-class User

Welcome to Grails 1.0 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0

Base Directory: D:\_DEV\grails_apps\demo
Environment set to development
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0\scripts\CreateDomainClass.groovy
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo\grails-app\domain
Created  for User
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo\test\integration
Created Tests for User
D:\_DEV\grails_apps\demo>

5,进入D:\Temp\grails_apps\demo\grails-app\domain(这个目录中存放着所有的domain class),打开User.groovy,修改为如下内容:
class  User { 
    String name
    String password
    
    String toString() {
        
" $name : $password "     
    }
    
    
static  constraints  =  {
        name(blank: 
false )    
        password(blank: 
false , size:  6 .. 16 )
    }
}    
contraints这个类变量是定义一些约束的,比如name不能为空白,password不能为空白而且长度在6到16之间(包括6和16)

6,在“命令行”中输入“grails generate-all User”,为User产生所有CRUD操作需要的代码(如控制器UserController.groovy)和页面(如list.gsp),输出结果如下所示:
D:\_DEV\grails_apps\demo>grails generate-all User

Welcome to Grails 1.0 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0

Base Directory: D:\_DEV\grails_apps\demo
Environment set to development
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0\scripts\GenerateAll.groovy
    [mkdir] Created dir: D:\_DEV\grails_apps\demo\web-app\WEB-INF\lib
    [mkdir] Created dir: C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\classes
  [groovyc] Compiling 7 source files to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\classes
    [mkdir] Created dir: C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\resources\grails-app\i18n
[native2ascii] Converting 10 files from D:\_DEV\grails_apps\demo\grails-app\i18n to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\re
sources\grails-app\i18n
     [copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\classes
     [copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\resources
     [copy] Copying 1 file to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo
[0] spring.GrailsWebApplicationContext Refreshing org.codehaus.groovy.grails.commons.spring.GrailsWebApplicationContext@2b2057: display name [org
.codehaus.groovy.grails.commons.spring.GrailsWebApplicationContext@2b2057]; startup date [Tue Feb 05 23:26:45 CST 2008]; root of context hierarch
y
[16] spring.GrailsWebApplicationContext Bean factory for application context [org.codehaus.groovy.grails.commons.spring.GrailsWebApplicationConte
xt@2b2057]: org.springframework.beans.factory.support.DefaultListableBeanFactory@eebf17
Generating views for domain class User ...
Generating controller for domain class User ...
Finished generation for domain class User
D:\_DEV\grails_apps\demo>


7,修改demo\grails-app\controllers\UserController.groovy的内容为:
            
class UserController {

    def loginService 
// 新增的代码
    
    def index 
= { redirect(action:list,params:params) }

    
// the delete, save and update actions only accept POST requests
    def allowedMethods = [delete:'POST', save:'POST', update:'POST']

    def list 
= {
        
if(!params.max) params.max = 10
        [ userList: User.list( params ) ]
    }

    def show 
= {
        def user 
= User.get( params.id )

        
if(!user) {
            flash.message 
= "User not found with id ${params.id}"
            redirect(action:list)
        }
        
else { return [ user : user ] }
    }

    def delete 
= {
        def user 
= User.get( params.id )
        
if(user) {
            user.delete()
            flash.message 
= "User ${params.id} deleted"
            redirect(action:list)
        }
        
else {
            flash.message 
= "User not found with id ${params.id}"
            redirect(action:list)
        }
    }

    def edit 
= {
        def user 
= User.get( params.id )

        
if(!user) {
            flash.message 
= "User not found with id ${params.id}"
            redirect(action:list)
        }
        
else {
            
return [ user : user ]
        }
    }

    def update 
= {
        def user 
= User.get( params.id )
        
if(user) {
            user.properties 
= params
            
if(!user.hasErrors() && user.save()) {
                flash.message 
= "User ${params.id} updated"
                redirect(action:show,id:user.id)
            }
            
else {
                render(view:
'edit',model:[user:user])
            }
        }
        
else {
            flash.message 
= "User not found with id ${params.id}"
            redirect(action:edit,id:params.id)
        }
    }

    def create 
= {
        def user 
= new User()
        user.properties 
= params
        
return ['user':user]
    }

    def save 
= {
        def user 
= new User(params)
        
if(!user.hasErrors() && user.save()) {
            flash.message 
= "User ${user.id} created"
            redirect(action:show,id:user.id)
        }
        
else {
            render(view:
'create',model:[user:user])
        }
    }

    
// 新增的代码
    def login = {
        
if (request.method == 'POST') {
            User u 
= new User()
            u.properties 
= params
    
            
if (!u.validate()) {
                render(view:
'login', model:[user:u])
            }
    
            
if (params.name && params.password) {
    
                def user 
= loginService.check(u)
                
                
if (user) {
                    flash.message 
= "Welcome ${user.name}" 
                    render(view: 
"ok", model: [user: user])
                } 
else {
                    flash.error 
= "Invalid ${u.name} with ${u.password}"
                    render(view: 
"login", model: [user: u])
                }    
            } 
else {
                render(view: 
"login", model: [user: u])
            }
        }
    }
}

大家或许也看到了LoginService这个类,我将在后面演示创建它,这个LoginService类封装了所有登陆相关的业务逻辑,Grails会自动将其注入到UserController中

8,在“命令行”中,输入“grails create-service Login”,创建LoginService.groovy,输出:
D:\_DEV\grails_apps\demo>grails create-service Login

Welcome to Grails 1.0 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0

Base Directory: D:\_DEV\grails_apps\demo
Environment set to development
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0\scripts\CreateService.groovy
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo\grails-app\services
Created Service for Login
     [copy] Copying 1 file to D:\_DEV\grails_apps\demo\test\integration
Created ServiceTests for Login
D:\_DEV\grails_apps\demo>

9,修改demo\grails-app\services\LoginService.groovy的内容为:
class LoginService {

    
boolean transactional = true

    def check(User u) {
        def user 
= User.findWhere(name: u.name, password: u.password)
        
return user
    }

}

10,在demo\grails-app\views\user目录下创建login.gsp和ok.gsp,它们对应MVC中的View,内容分别为:
login.gsp (复制demo\grails-app\views\user\create.gsp的内容到login.gsp中,并修改):



<html>
    
<head>
        
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        
<meta name="layout" content="main" />
        
<!-- 将Create User修改为Login -->
        
<title>Login</title>         
    
</head>
    
<body>
        
<div class="nav">
            
<span class="menuButton"><class="home" href="${createLinkTo(dir:'')}">Home</a></span>
            
<span class="menuButton"><g:link class="list" action="list">User List</g:link></span>
        
</div>
        
<div class="body">
            
<!-- 将Create User修改为Login -->
            
<h1>Login</h1>
            
<!-- 将flash.message修改为flash.error -->
            
<g:if test="${flash.error}">
            
<!-- 将class="message"修改为class="errors", 将flash.message修改为flash.error -->
            
<div class="errors">${flash.error}</div>
            
</g:if>
            
<g:hasErrors bean="${user}">
            
<div class="errors">
                
<g:renderErrors bean="${user}" as="list" />
            
</div>
            
</g:hasErrors>
            
            
<!-- 将action="save"修改为action="login" -->
            
<g:form action="login" method="post" >
                
<div class="dialog">
                    
<table>
                        
<tbody>
                        
                            
<tr class="prop">
                                
<td valign="top" class="name">
                                    
<label for="name">Name:</label>
                                
</td>
                                
<td valign="top" class="value ${hasErrors(bean:user,field:'name','errors')}">
                                    
<input type="text" id="name" name="name" value="${fieldValue(bean:user,field:'name')}"/>
                                
</td>
                            
</tr> 
                        
                            
<tr class="prop">
                                
<td valign="top" class="name">
                                    
<label for="password">Password:</label>
                                
</td>
                                
<td valign="top" class="value ${hasErrors(bean:user,field:'password','errors')}">
                                    
<input type="text" maxlength="16" id="password" name="password" value="${fieldValue(bean:user,field:'password')}"/>
                                
</td>
                            
</tr> 
                        
                        
</tbody>
                    
</table>
                
</div>
                
<div class="buttons">
                    
<!-- 将value="Create"修改为value="Login" -->
                    
<span class="button"><input class="save" type="submit" value="Login" /></span>
                
</div>
            
</g:form>
        
</div>
    
</body>
</html>

ok.gsp:

<g:if test="${flash.message}">
    
<div class="message">${flash.message}</div>
</g:if>

Name: ${user?.name}   
<br>
Password: ${user?.password}

11,修改demo\grails-app\conf\BootStrap.groovy,初始化数据库:将一个User实例保存到数据库(grails自带hsqldb和jetty)中,内容如下:
class BootStrap {

     def init 
= { servletContext ->
        
new User(name: "demo", password: "123456").save()
     }

     def destroy 
= {
     }

12,在“命令行”中,输入“grails run-app”,运行我们的Web应用,输出如下:
D:\_DEV\grails_apps\demo>grails run-app

Welcome to Grails 1.0 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:\D\MY_DEV\grails-1.0

Base Directory: D:\_DEV\grails_apps\demo
Environment set to development
Note: No plugin scripts found
Running script D:\D\MY_DEV\grails-1.0\scripts\RunApp.groovy
  [groovyc] Compiling 4 source files to C:\Documents and Settings\Daniel\.grails\1.0\projects\demo\classes
Running Grails application..
2008-02-05 23:46:08.912::INFO:  Logging to STDERR via org.mortbay.log.StdErrLog
2008-02-05 23:46:08.066::INFO:  jetty-6.1.4
2008-02-05 23:46:08.347::INFO:  No Transaction manager found - if your webapp requires one, please configure one.
2008-02-05 23:46:09.081:/demo:INFO:  Set web app root system property: 'demo' = [D:\_DEV\grails_apps\demo\web-app\]
2008-02-05 23:46:09.081:/demo:INFO:  Initializing Log4J from [file:C:\Documents and Settings\Daniel/.grails/1.0/projects/demo/resources/log4j.pro
perties]
2008-02-05 23:46:09.113:/demo:INFO:  Initializing Spring root WebApplicationContext
[0] spring.GrailsWebApplicationContext Refreshing org.codehaus.groovy.grails.commons.spring.GrailsWebApplicationContext@5facbd: display name [org
.codehaus.groovy.grails.commons.spring.GrailsWebApplicationContext@5facbd]; startup date [Tue Feb 05 23:46:14 CST 2008]; parent: org.springframew
ork.web.context.support.XmlWebApplicationContext@1fef80a
[0] spring.GrailsWebApplicationContext Bean factory for application context [org.codehaus.groovy.grails.commons.spring.GrailsWebApplicationContex
t@5facbd]: org.springframework.beans.factory.support.DefaultListableBeanFactory@aa4c7c
2008-02-05 23:46:21.590:/demo:INFO:  Initializing Spring FrameworkServlet 'grails'
2008-02-05 23:46:21.871::INFO:  Started SelectChannelConnector@0.0.0.0:8080
Server running. Browse to http://localhost:8080/demo

 
13,打开浏览器,输入:http://localhost:8080/demo/user/login ,在Name处输入demo,Password处输入123456,点击‘Login’,跳转到成功页面:
Welcome demo
Name: demo
Password: 123456

如果您对Grails的工程目录不太熟悉,我这里为大家提供了一张表,详细地描述了各目录的用途:

《Grails权威指南》3-1.Grails工程目录

目录名称

相关描述

grails-app

此目录包含了Grails应用程序的核心工件(core artifact)

+ conf

此目录包含了诸如DevelopmentDataSource.groovy的配置文件

+ controllers

此目录包含了处理请求(request)的控制器(controller)Grails控制器将在第7章中进行讲解

+ domain

此目录包含了领域模型(domain model),领域模型将在第4章进行讲解

+ i18n

此目录包含了用于国际化的消息束(message bundle)(译者注:指的是properties文件,如messages.properties

+ services

此目录包含了封装业务逻辑的service文件,service将在第10章中进行讲解

+ taglib

此目录包含了辅助页面生成的动态标签库,动态标签将在第8章中进行讲解

+ views

此目录包含了Groovy服务器页面(GSP)以及JSP页面

+ layouts

此目录包含了GSPJSP的布局(layout),这些布局由SiteMesh提供支持,这将在第8章中进行讲解

grails-test

此目录包含了应用程序的单元测试

hibernate

此目录包含了可选的Hibernate配置文件,这将在第11章中进行讲解

lib

此目录包含了jar文件

spring

此目录包含了可选的Spring配置文件,这将在第11章中进行讲解

src

此目录包含了其他GroovyJava资源

+ java

此目录包含了待编译的Java源文件

+ groovy

此目录包含了待编译的Groovy源文件

web-app

此目录包含了Web应用程序的资源(CSSJavaScript等)


注:Grails1.0已将hibernate和spring两个目录移到grails-app\conf目录下了,
而grails-test目录也更名为test,test目录下有integration目录和unit目录,分别存放集成测试代码和单元测试代码


想象一下用您平时做项目时所用的框架组合(比如SSH)来创建同样的Web应用程序,您立刻会感受,Grails让我们专注于业务逻辑,而不用浪费时间在那些scaffolding code(如配置文件)上。从今天开始,您不用再羡慕那些Ruby程序员所用的RoR了,您大可以使用Grails来高效开发Web应用。

您也可以访问Grails官方网站(http://www.grails.org)进一步学习。

附:朝花夕拾——Groovy & Grails
posted on 2007-03-21 00:49 山风小子 阅读(19170) 评论(31)  编辑  收藏 所属分类: Groovy & Grails