This article analyzes a JS long integer accuracy problem. Share it for your reference. The specific analysis is as follows:
Problem description:
There is a script function in the background, which can write scripts to call Java code dynamically
The code copy is as follows: importClass(com.ztgame.center.controller.api,P360ApiController);
var roleId = 10214734953631045;
p360ApiController.Notice(roleId, 4);
The script was executed successfully, but the running result was different from the settings. This person did not receive the email
View the log recharge award has been sent. roleId=10214734953631044;
This character ID number is 1 less, this...
Problem analysis:
It should be a JS precision issue.
Accuracy
An integer (without decimal or exponential counting) is up to 15 digits.
The maximum number of digits of a decimal is 17, but floating point operations are not always 100% accurate:
Modify the script
The code copy is as follows: var roleId = 10214734953631045;
var output = roleId;
Output:
1.0214734953631044E16;
This is not the fault of JavaScript, nor is it the fault of Java. The above conversion to Long is indeed roleId=10214734953631044;
Can that be done?
The javascript console inputs strings, and then calls Integer.valueOf or Long.valueOf conversion in java?
Solution:
Write a general conversion method to pass the role ID into a string to JavaScriptEngine
The code copy is as follows: importClass(com.ztgame.common.util.StringKit);
importClass(com.ztgame.center.controller.api,P360ApiController);
Declare as a string
The code copy is as follows: var roleId = "10214734953631045";
In this way, what JavaScriptEngine gets is a string. In fact, the job is Java to process it.
The code copy is as follows: p360ApiController.Notice(StringKit.parseLong(roleId), 4);
The execution is successful, just use it first~
I hope this article will be helpful to everyone's JavaScript programming.