JSON中optString()和getString()区别

The difference is that 

optString

 returns
the empty string (

""

)
if the key you specify doesn't exist.

getString

 on
the other hand throws a 

JSONException

.
Use 

getString

 if
it's an error for the data to be missing, or 

optString

 if
you're not sure if it will be there.

简而言之：optString对应的key中值不存在返回空字符串”“或者是你指定的默认值，而getString会抛出JSONException异常。