Rails简单练习

最新推荐文章于 2025-05-12 10:06:56 发布

flyflyfly55555

最新推荐文章于 2025-05-12 10:06:56 发布

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分类专栏： rails 文章标签： Rails Ajax ActiveRecord JavaScript Flash ViewUI

本文链接：https://blog.youkuaiyun.com/flyflyfly55555/article/details/83640810

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对Rails的一个简单的练习

一个学生和教师的CRUD，以及简单的ajax应用。学生和教师为多对一得关系

model为：

class Student < ActiveRecord::Base
  belongs_to :teacher
end
class Teacher < ActiveRecord::Base
  has_many :students,:dependent=>:delete_all
end

migrate为：

class CreateTeachers < ActiveRecord::Migration
  def self.up
    create_table :teachers,:force=>true do |t|
      t.column :name,:string
    end
  end

  def self.down
    drop_table :teachers
  end
end

class CreateStudents < ActiveRecord::Migration
  def self.up
    create_table :students,:force=>true do |t|
      t.column :name,:string
      t.column :teacher_id,:integer
      add_index :students,:teacher_id
    end
  end

  def self.down
    drop_table :students
  end
end

执行rake db:migrate 后，可以看到没有在数据库中使用外键，只是在teachar_id上面增加了索引

控制器代码：功能为列出所有的学生和教师，增加和删除学生与教师

#coding:utf-8
class HomeController < ApplicationController
  #默认页面
  def index
    list
    render :action => "index"
  end

  # 如果提交的姓名不为空，则增加学生，然后跳转到index
  def new
    # 如果姓名不为空则执行保存操作
    if check_n
      entity = Student.new
      unless params[:teacher_id].nil?
        unless params[:teacher_id]=="0"
          entity.teacher = Teacher.find params[:teacher_id]
        end
      end
      if check_type == "teacher"
        entity = Teacher.new
      end
      entity.name = @name
      entity.save
      flash[:error] = "OK"
    end
    redirect_to :action => "index"
  end

  # 删除学生/老师
  def delete
    begin
      # 根据类型进行判断，执行对应代码
      logger.debug "debug================================="
      logger.debug "the type and id is type:#{params[:type]},id:#{params[:id]}"
      if params[:type] and params[:type]=="student"
        Student.destroy(params[:id])
      else
        t = Teacher.find params[:id]
        # 取得级联删除的学生的id
        id_array = t.student_ids.to_s
        t.destroy
        logger.debug "debug================================="
        logger.debug "the array is #{id_array.to_s}"
      end
    rescue =>e
      logger.debug(e)
      #如果删除失败则不返回任何信息
      # render :text => e.to_s
      return
    end
    # 如果是删除老师则返回一个包含有级联删除的学生id的数组字符串
    if id_array.nil?
      render :text => "OK"
    else
      render :text => id_array
    end
  end
  private
  # 列出所有的学生和老师
  def list
    @students = Student.find :all
    @teachers = Teacher.find :all
    @teacher_name = []
    for st in @students
      th = st.teacher
      unless th.nil?
        @teacher_name << st.teacher.name
      else
        @teacher_name << "none"
      end
      #        logger.debug "debug================================="
      #        logger.debug "the student's teacher is #{st.teacher}"
    end
  end
  # 检测提交的姓名是否为空
  def check_n
    @name = params[:name]
    logger.debug "debug================================="
    logger.debug "this name is #{@name}"
    if @name.nil? or @name.strip.empty?
      flash[:error] = "name should not be empty."
      return false
    else
      return true
    end
  end
  #判断要保存的是学生还老师
  def check_type
    type = params[:type]
    logger.debug "debug================================="
    logger.debug "the type is #{type}"
    if type.nil?
      raise "未知的类型。"
    elsif type == "student"
      return type
    elsif type == "teacher"
      return type
    else
      raise "未知的类型"
    end
  end
end

index.rhtml如下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <base href="/"/> 
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <title>test</title>
    <script type="text/javascript" src="javascripts/prototype.js"></script>
    <script type="text/javascript">
      function addEvent(){
        //为每个a标签注册单击事件
        $$("a").each(function(a){
          a.observe("click",deleteEntity)
        })
      }
      //给教师列表注册时间晕
      function teacherList(){
        select = document.getElementById("type")
        value = select.options[select.selectedIndex].text
        if (value=="学生")
          $('teacher_id').show()
        else{
          $("teacher_id").hide()
        }
      }
      // 取得数据的id和类型然后调用Ajax请求
      function deleteEntity(e){
        a = Event.element(e)
        //取得a标签的id内容,此为要删除的数据在数据库中的主键id
        id = a.identify()
        type = "student"
        if(a.hasClassName("teacher")){
          type="teacher"
        }
        //向后台发送删除请求晕
        ajax(a,id,type)
      }
      function ajax(a,id,type){
        //  alert(id)
        new Ajax.Request("home/delete",{parameters:{id:id,type:type},onSuccess:callback})
        function callback(data){
          //取得服务器返回的处理结果
          var result = data.responseText
          removeLi(a)
          //如果返回的不是OK,则刷新学生列表晕
          if (result!="OK")
            refreshList(result)
        }
      }
      function refreshList(array){
        ids = eval(array)
        if(ids.length==0) return
        $$("ul")[0].childElements().each(function(li){
          li.childElements().each(function(a){
            id = a.identify()
            for(i=0;i<ids.length;i++){
              if (id == ids[i])
                removeLi(a)
            }
          })
        })
      }
      function removeLi(a){
        a.ancestors()[0].remove()
      }
      // 添加事件
      Event.observe(window,"load",addEvent)
    </script>
  </head>
  <body>
    <p>所有学生：</p>
    <ul>
      <% @students.each_index do |index| %>
        <li>
          学生姓名:<%=@students[index].name%>
          所属的教师:<%=@teacher_name[index]%>
          <a  href="javascript:void(0);" class="student" id="<%=@students[index].id%>">删除</a>
        </li>
      <%end%>
    </ul>
    <p>所有教师：</p>
    <ul>
      <% @teachers.each do |teacher| %>
        <li>
          教师姓名:<%=teacher.name%>
          <a href="javascript:void(0);" class="teacher" id="<%=teacher.id%>">删除</a>
        </li>
      <%end%>
    </ul>
    <p />
    <hr />
    <p>增加学生/教师<br /></p>
    <% form_tag("home/new") do-%>
      姓名:<input name="name"/>
      <p />
      类别:
      <select onchange="teacherList()" name="type" id="type">
        <option value="student">学生</option>
        <option value="teacher">教师</option>
      </select>
      <div id="teacher_id">
        所属的教师:
        <select name="teacher_id">
          <option value="0">暂无</option>
          <% @teachers.each do |teacher| %>
            <option value="<%=teacher.id%>"><%=teacher.name%></option>
          <%end%>
        </select>
      </div>
      <p />
      <input type="submit" value="确定"/>
    <%end-%>
    <p>处理结果:<span style="color: red"><%=flash[:error]%></span></p>
  </body>
</html>

上面的

//给教师列表注册时间晕

//向后台发送删除请求晕

最后的'晕'如果不加上，就会出现这个错误 invalid byte sequence in GBK。很诡异啊，可能是bug吧。看了下rubyAPI文档，发现添加Encoding.default_internal="UTF-8"和Encoding.default_external="UTF-8"到application_controller.rb中就可以解决这个诡异的问题。

还有个问题：如果表单输入中文，即数据库中存入中文时还是会报 incompatible character encodings: GBK and ASCII-8BIT的错误

ruby为ruby1.9.1版本

rails为rails2.3.8版本