chore:optimize the exception code

[leizhiyuan]

Motivation:

Explain the context, and why you're making that change.
To make others understand what is the problem you're trying to solve.

Modification:

Describe the idea and modifications you've done.

Result:

Fixes ##818

If there is no issue then describe the changes introduced by this PR.

[codecov-io]

Codecov Report

Merging #829 into master will decrease coverage by 0.17%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master     #829      +/-   ##
============================================
- Coverage     71.92%   71.74%   -0.18%     
+ Complexity     1092     1089       -3     
============================================
  Files           376      376              
  Lines         15418    15422       +4     
  Branches       2474     2474              
============================================
- Hits          11089    11065      -24     
- Misses         3050     3075      +25     
- Partials       1279     1282       +3

Impacted Files	Coverage Δ	Complexity Δ
...in/java/com/alipay/sofa/rpc/log/LoggerFactory.java	38.09% <0%> (-8.97%)	0 <0> (ø)
...java/com/alipay/sofa/rpc/module/LookoutModule.java	52.38% <0%> (-33.34%)	3% <0%> (-1%)
...m/alipay/sofa/rpc/module/FaultToleranceModule.java	63.63% <0%> (-31.82%)	4% <0%> (-1%)
...pay/sofa/rpc/transport/ClientTransportFactory.java	72.3% <0%> (-4.62%)	0% <0%> (ø)
.../main/java/com/alipay/sofa/rpc/event/EventBus.java	70.58% <0%> (-1.97%)	0% <0%> (ø)
...va/com/alipay/sofa/rpc/server/bolt/BoltServer.java	74.48% <0%> (-1.03%)	24% <0%> (-1%)
...va/com/alipay/sofa/rpc/client/AbstractCluster.java	67.47% <0%> (-0.61%)	0% <0%> (ø)
...alipay/sofa/rpc/registry/zk/ZookeeperRegistry.java	62.65% <0%> (-0.61%)	0% <0%> (ø)
...ay/sofa/rpc/client/AllConnectConnectionHolder.java	62.59% <0%> (-0.27%)	0% <0%> (ø)

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[ujjboy]

LGTM