小编Gen*_*hyn的帖子

更改(:hour => 1)在rails控制台中正常工作

irb(main):004:0> dt = DateTime.now
=> Mon, 10 Dec 2012 15:52:01 -0800
irb(main):005:0> _.change(:hour => 1)
=> Mon, 10 Dec 2012 01:00:00 -0800
irb(main):006:0>
irb(main):007:0> dt.class
=> DateTime
irb(main):008:0>

但是在irb中引发了"未定义的方法`改变'"

irb(main):008:0> require 'active_record'
=> true
irb(main):009:0> dt = DateTime.now
=> #<DateTime: 2012-12-10T15:55:14-08:00 (10611097185737/4320000,-1/3,2299161)>
irb(main):010:0> dt.class
=> DateTime
irb(main):011:0> dt.change(:hour => 1)
NoMethodError: undefined method `change' for #<DateTime:0x53e20a9a>
        from (irb):11:in `evaluate'
        from org/jruby/RubyKernel.java:1070:in `eval'
        from org/jruby/RubyKernel.java:1395:in `loop'
        from org/jruby/RubyKernel.java:1178:in `catch'
        from org/jruby/RubyKernel.java:1178:in `catch'
        from C:\PF\jruby-1.7.0.preview2\bin\irb:13:in `(root)'
irb(main):012:0>

有什么建议如何使其工作？

提前致谢.