[SCB-2467] use standard Integer#compareTo(···) method

[david6969xin]

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[hezhangjian]

@david6969xin this is a bug fix or improvment?

[codecov-commenter]

Codecov Report

Merging #2804 (6dee387) into master (7faf4bc) will increase coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff            @@
##             master    #2804   +/-   ##
=========================================
  Coverage     77.30%   77.30%           
  Complexity     1418     1418           
=========================================
  Files          1616     1616           
  Lines         43315    43313    -2     
  Branches       3667     3666    -1     
=========================================
+ Hits          33483    33484    +1     
+ Misses         8297     8296    -1     
+ Partials       1535     1533    -2     

Impacted Files	Coverage Δ
...org/apache/servicecomb/router/model/RouteItem.java	57.14% <0.00%> (+3.80%)	⬆️
...mb/config/ConfigCenterConfigurationSourceImpl.java	9.78% <0.00%> (-1.09%)	⬇️
.../servicecomb/registry/discovery/DiscoveryTree.java	100.00% <0.00%> (+3.50%)	⬆️

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[david6969xin]

@david6969xin this is a bug fix or improvment?
improvment

[hezhangjian]

@david6969xin I would suggest replace all pattern of this.
cc @liubao68

[david6969xin]

@shoothzj only one that satisfies this pattern