Grails 快速入门(二)

这一篇快速过一遍这套框架有什么特性…

Controllers Usage

• actionName
• controllerName

吃瓜群众不明白

• allowedMethods (约束请求方法)
• bindData

关于 bindDate 的使用

• chain
• defaultAction
• errors
• flash
• forward
• grailsApplication
• hasErrors
• namespace
• params
• redirect
• render

关于 render 的使用

从官网来看 http://docs.grails.org/latest/ref/Controllers/render.html
返回的类型主要有:可指定编码格式的文本、模板的渲染 template [model、collection、bean]、直接渲染视图、markup、XML、JSON、HTTP状态码、文件

// Automatic marshalling of XML and JSON
import grails.converters.*
…
render Book.list(params) as JSON
render Book.get(params.id) as XML
// render a file
render(file: new File(absolutePath), fileName: "book.pdf")

• request
• respond
• response
• responseFormats
• scope
• servletContext
• session
• withForm
• withFormat

从domain中获取数据并遍历

上一个教程完整地建立了一个domain(其实我改了很多东西了..)

Service Usage

我们使用 Service 进行操作我们的domain , 需要注意的是

• In Grails a service is a class with a name that ends in the convention “Service” and lives in the grails-app/services directory.)

上面的意思大概就是你的 Service 必须命名于 Service 后缀(使用插件就自动帮你补全) 且 放在 /services 中.

Domain Usage

关于高级的使用(高质量的干货) : http://sysgears.com/articles/advanced-gorm-features-inheritance-embedded-data-maps-and-lists-storing/

• addTo

  处理表之间的关系 one-to-many or many-to-many relationship

  
  def fictBook = new Book(title: "IT")
  def nonFictBook = new Book(title: "On Writing: A Memoir of the Craft")
  def a = new Author(name: "Stephen King")
           .addToFiction(fictBook)
           .addToNonFiction(nonFictBook)
           .save()
  
  
  class Author {
  String name
  static hasMany = [fiction: Book, nonFiction: Book]
  }
  class Book {
      String title
       static belongsTo = [author: Author]
  }
  

• attach

  配合 isAttached() ,关联已经被 discard() 的实例到当前的会话中

  def b = Book.get(1)
  b.title = "Blah"
  b.save(flush:true)
  b.discard()
  …
  if (!b.isAttached()) {
     b.attach()
  }

• belongsTo

  一对多

• clearErrors

  清楚错误的信息,用于 validate() 之后

  
      def b = new Book(title: "The Shining")
      b.validate()
      if (b.hasErrors()) {
          // clear the list of errors
          b.clearErrors()
          // fix the validation issues
          b.author = "Stephen King"
          // re-validate
          b.validate()
      }
  
  

• constraints

  声明验证约束

  
    static constraints = {
      title blank: false, size: 5..150
      author nullable: true
  }
  

• count

  总计对象的行数

• countBy

  这个是动态查询,能够无限的延长(怎么用就不知道了),科科,大概就是三十一个…

• createCriteria

  详细操作 http://docs.grails.org/latest/ref/Domain%20Classes/createCriteria.html

• delete

  冬眠实例..并立刻删除

  
  book.delete(flush: true)
  
  

• discard

  不被保存

• embedded

  将同一张表的内容进行划分,便于理解与操作

• errors

  配合validate使用

  
  def user = new User(params)
  if (user.validate()) {
      // do something with user
  }
  else {
      user.errors.allErrors.each {
          println it
      }
  }
  
  

• executeQuery

  执行 HQL

• executeUpdate

• exists

• fetchMode

• find

• findAll

• findAllBy

• findAllWhere

• findBy

• findOrCreateBy

• findOrCreateWhere

• findOrSaveBy

• findOrSaveWhere

• findWhere

• first

• get

• getAll

• getDirtyPropertyNames

• getPersistentValue

• hasErrors

• hasMany

• hasOne

• ident

• instanceOf

• isAttached

• isDirty

• last

• list

• listOrderBy

• load

• lock

• mapWith

• mappedBy

• mapping

• merge

• namedQueries

• properties

• read

• refresh

• removeFrom

• save

• transients

• validate

• where

• whereAny

• withCriteria

• withNewSession

• withSession

• withTransaction