Groovy轻松入门——Grails实战之Ajax篇

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Groovy轻松入门——Grails实战之Ajax篇

2019年09月24日 ⁄ 综合 ⁄ 共 12904字 ⁄ 字号小中大 ⁄ 评论关闭

Ajax虽是“旧酒装新瓶”，但其威力着实不小。近两年来可谓红透半边天，它之所以能为大众接受，其中一个很大的原因就是提高了用户浏览体验，能更逼真的模拟出GUI界面。好了，Ajax的益处就说到这里，下面让我们看下Grails是如何帮助我们方便地应用Ajax的:

如果您对下面说设计的内容有点不解，那么您可以先看一下 Groovy轻松入门——Grails实战基础篇，然后开始我们的Ajax之旅。

1, 在命令行中输入：“grails create-app AjaxDemo”（注意：不带引号“”）创建一个Grails project，我将它命名为AjaxDemo：

D:/Temp/grails_apps>grails create-app AjaxDemo

Welcome to Grails 0.5 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:/D/MY_DEV/grails-0.5

Base Directory: D:/Temp/grails_apps
Environment set to production
Note: No plugin scripts found
Running script D:/D/MY_DEV/grails-0.5/scripts/CreateApp.groovy
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/src
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/src/java
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/src/groovy
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/src/test
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/controllers
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/jobs
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/services
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/domain
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/taglib
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/utils
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/views
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/views/layouts
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/i18n
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-app/conf
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/grails-tests
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/scripts
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/js
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/css
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/images
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/classes
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/META-INF
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/lib
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/spring
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/hibernate
[propertyfile] Creating new property file: D:/Temp/grails_apps/AjaxDemo/application.properties
     [copy] Copying 2 files to D:/Temp/grails_apps/AjaxDemo
     [copy] Copying 2 files to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF
     [copy] Copying 5 files to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/tld
     [copy] Copying 119 files to D:/Temp/grails_apps/AjaxDemo/web-app
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-app/conf
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-app/conf
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-app/conf
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-app/conf
     [copy] Copying 13 files to D:/Temp/grails_apps/AjaxDemo/grails-app
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/plugins/core/grails-app/taglib
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/plugins/core/grails-app/utils
     [copy] Copying 7 files to D:/Temp/grails_apps/AjaxDemo/plugins/core/grails-app/taglib
     [copy] Copying 4 files to D:/Temp/grails_apps/AjaxDemo/plugins/core/grails-app/utils
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/spring
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo
[propertyfile] Updating property file: D:/Temp/grails_apps/AjaxDemo/application.properties
Created Grails Application at D:/Temp/grails_apps/AjaxDemo
D:/Temp/grails_apps>

2，“cd AjaxDemo”，进入AjaxDemo目录，输入“grails create-domain-class User”，创建一个域类User：

D:/Temp/grails_apps/AjaxDemo>grails create-domain-class User

Welcome to Grails 0.5 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:/D/MY_DEV/grails-0.5

Base Directory: D:/Temp/grails_apps/AjaxDemo
Environment set to production
Running script D:/D/MY_DEV/grails-0.5/scripts/CreateDomainClass.groovy
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-app/domain
Created  for User
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/grails-tests
Created Tests for User
D:/Temp/grails_apps/AjaxDemo>

3，“grails generate-all User”，生成scaffolding code（如：list.gsp等）：

D:/Temp/grails_apps/AjaxDemo>grails generate-all User

Welcome to Grails 0.5 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: D:/D/MY_DEV/grails-0.5

Base Directory: D:/Temp/grails_apps/AjaxDemo
Environment set to production
Running script D:/D/MY_DEV/grails-0.5/scripts/GenerateAll.groovy
Compiling sources
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/lib
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/spring
     [copy] Copying 34 files to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/lib
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/grails-app/i18n
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/grails-app/views
     [copy] Copying 2 files to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/grails-app/views
    [mkdir] Created dir: D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/templates/scaffolding
     [copy] Copying 5 files to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/templates/scaffolding
[native2ascii] Converting 7 files from D:/Temp/grails_apps/AjaxDemo/grails-app/i18n to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/grails-app/i1
8n
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/spring
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/classes
     [copy] Copying 1 file to D:/Temp/grails_apps/AjaxDemo/web-app/WEB-INF/classes
Generating views for domain class [User]
Generating list view for domain class [User]
list view generated at D:/Temp/grails_apps/AjaxDemo/./grails-app/views/user/list.gsp
Generating show view for domain class [User]
Show view generated at D:/Temp/grails_apps/AjaxDemo/./grails-app/views/user/show.gsp
Generating edit view for domain class [User]
Edit view generated at D:/Temp/grails_apps/AjaxDemo/./grails-app/views/user/edit.gsp
Generating create view for domain class [User]
Create view generated at D:/Temp/grails_apps/AjaxDemo/./grails-app/views/user/create.gsp
Generating controller for domain class [User]
Controller generated at ./grails-app/controllers/UserController.groovy
D:/Temp/grails_apps/AjaxDemo>

4，修改AjaxDemo/grails-app/controllers/UserController.groovy的内容为：

class UserController {
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 = {
        [ user : User.get( params.id ) ]
    }

    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.save()) {
                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()
        user.properties = params
         if (user.save()) {
            redirect(action:show,id:user.id)
        }
         else {
            render(view: ' create ' ,model:[user:user])
        }
    }

     // 自己添加的Closure ajax定义
    def ajax = {}

     // 自己添加的Closure sayHello定义
    def sayHello = {
        render " [${new Date()}] Hello, ${params.name} "
    }

}

添加sayHello闭包的目的很明显，因为客户端需要调用。那为什么还要添加ajax这个闭包呢？其实添加 ajax 这个闭包的目的是使http://localhost:8080/AjaxDemo/user/ ajax 这个请求合法化，否则会发生404错误，找不到页面：

HTTP ERROR: 404

Not Found

RequestURI=/AjaxDemo/user/ajax

Powered by Jetty://

所以被客户端请求的每个 gsp页面，都需要在相应的Controller中添加以gsp文件名为变量名的Closure，如上面的ajax.gsp和ajax = {}所示，其中Closure中可以添加相关代码，我们这里仅仅是做Ajax的演示，所以就不需要代码

5，在AjaxDemo/grails-app/views/user目录下，新建ajax.gsp，用来演示remoteLink的用法，内容为：

< g:javascript library ="prototype" />

< div id ="hello" > Content will be displayed here </ div >

< g:remoteLink action ="sayHello" params ="[name:'BlueSUN']" update ="hello" >Say Hello </ g:remoteLink >

params表示要传递的参数，而update表示返回结果显示的地方，注意update="hello"中的hello对应于div的id，表示结果将显示于div所在处。

点击链接后的界面：

[Fri May 11 17:46:47 CST 2007] Hello, BlueSUN

Say Hello

6，修改AjaxDemo/grails-app/views/user/ ajax.gsp，演示formRemote的用法，内容为：

<g:javascript library="prototype" />

<div id="hello">Content will be displayed here</div>
<div id="error"></div>

<g:remoteLink action="sayHello" params="[name:'BlueSUN']" update="hello">Say Hello</g:remoteLink>

<hr />

<g:formRemote name="test" url="[controller:'user',action:'sayHello']" update="[success:'hello',failure:'error']">
<input type="text" name="name" value="BlueSUN" />
<input type="submit" value="Say Hello" />
</g:formRemote >

原本用params传递的参数，现在可以以form的形式传递了，将想传递的内容输入name的textfield中即可。

默认值我设为BlueSUN，现在我将值改为terry，点击Say Hello按钮，结果如下：

[Fri May 11 18:16:17 CST 2007] Hello, terry

Say Hello

7，修改AjaxDemo/grails-app/views/user/ ajax.gsp和AjaxDemo/grails-app/controllers/UserController.groovy，演示remoteField的用法：
ajax.gsp:

<g:javascript library="prototype" />

<div id="hello">Content will be displayed here</div>
<div id="error"></div>

<g:remoteLink action="sayHello" params="[name:'BlueSUN']" update="hello">Say Hello</g:remoteLink>

<hr />

<g:remoteField action="sayHello2" update="hello" name="name" value="" />

UserController.groovy:

class UserController {
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 = {
        [ user : User.get( params.id ) ]
    }

    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.save()) {
                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()
        user.properties = params
        if(user.save()) {
            redirect(action:show,id:user.id)
        }
        else {
            render(view:'create',model:[user:user])
        }
    }

    // 自己添加的Closure ajax定义
    def ajax = {}

    // 自己添加的Closure sayHello定义
    def sayHello = {
        render "[${new Date()}] Hello, ${params.name}"
    }

    // 自己添加的Closure sayHello2定义
    def sayHello2 = {
        render "[${new Date()}] Hello, ${params.value}"
    }

}

由于用remoteField传递过来的参数名为value，又为了保留以前的演示，所以再定义一个sayHello2闭包，注意是params.value而非params.name

【上篇】网页图标
【下篇】grails中配置文件的读取[适用1.0RC1+]

作者: speculate

该日志由 speculate 于5年前发表在综合分类下，最后更新于 2019年09月24日.
转载请注明: Groovy轻松入门——Grails实战之Ajax篇 | 学步园 +复制链接

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