由于缺少Mime JSON而无法启动rake任务

如何解决由于缺少Mime JSON而无法启动rake任务

在本地安装存储库并绑定Rails 4.0应用程序后，将创建数据库

rake db:create

命令失败，返回以下错误：

uninitialized constant Mime::JSON

从application.rb调用这一行

Bundler.require(:default,Rails.env)

此行的开头是：

require File.expand_path('../boot',__FILE__)

require 'rails/all'

如何使耙子正确处理？

**更新** 根据请求，全栈跟踪如下。我确实设法通过删除jbuilder gem来避免错误。

NameError: uninitialized constant Mime::JSON
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/jbuilder-1.5.3/lib/jbuilder/jbuilder_template.rb:110:in `<class:JbuilderHandler>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/jbuilder-1.5.3/lib/jbuilder/jbuilder_template.rb:108:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/jbuilder-1.5.3/lib/jbuilder.rb:358:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:74:in `require'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:74:in `block (2 levels) in require'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:69:in `each'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:69:in `block in require'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:58:in `each'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/runtime.rb:58:in `require'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler.rb:174:in `require'
/Volumes/Mo/r/uelcom/config/application.rb:7:in `<top (required)>'
/Volumes/Mo/r/uelcom/Rakefile:8:in `require'
/Volumes/Mo/r/uelcom/Rakefile:8:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/rake_module.rb:29:in `load'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/rake_module.rb:29:in `load_rakefile'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:703:in `raw_load_rakefile'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:104:in `block in load_rakefile'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:186:in `standard_exception_handling'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:103:in `load_rakefile'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:82:in `block in run'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:186:in `standard_exception_handling'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/lib/rake/application.rb:80:in `run'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/bin/rake:23:in `load'
/Users/deploy/.rbenv/versions/2.6.1/bin/rake:23:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli/exec.rb:63:in `load'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli/exec.rb:63:in `kernel_load'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli/exec.rb:28:in `run'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli.rb:476:in `exec'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/vendor/thor/lib/thor.rb:399:in `dispatch'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli.rb:30:in `dispatch'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/vendor/thor/lib/thor/base.rb:476:in `start'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/cli.rb:24:in `start'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/exe/bundle:46:in `block in <top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/lib/bundler/friendly_errors.rb:123:in `with_friendly_errors'
/Users/deploy/.rbenv/versions/2.6.1/lib/ruby/gems/2.6.0/gems/bundler-2.1.4/exe/bundle:34:in `<top (required)>'
/Users/deploy/.rbenv/versions/2.6.1/bin/bundle:23:in `load'
/Users/deploy/.rbenv/versions/2.6.1/bin/bundle:23:in `<main>'

解决方法

似乎您正在使用5或以上的滑轨。

从Rails版本5或更高版本开始，不赞成通过Mime::JSON访问Mime类型，我们需要以Mime[:json]的身份访问它

请找到以下相同参考文献-Release Note和Pull request

不建议通过常量（例如Mime :: HTML）访问mime类型。请使用带符号的下标运算符（例如Mime [：html]）

---

根据您提供的异常的回溯信息，宝石jbuilder导致了问题，它以不推荐使用的Mime::JSON访问Mime类型。

请找到在gem jbuilder-Jubilder - Github上导致错误的行的引用。

您使用的是jbuilder(1.5.3)的旧版本，请将此gem升级到最新版本，然后尝试

尝试以下版本：

Gemfile

gem 'jbuilder','~> 2.10'