具有Mongo Java驱动程序的DB.eval() [英] DB.eval() with Mongo Java Driver

问题描述

我已经准备了一些要在Mongo上执行的脚本. 它可以从命令行按预期工作:

I've prepared some script to execute on Mongo. It works as expected from command line:

mongo 127.0.0.1:27017/dbName script.js

但是当我尝试在Java(scala)代码中移动它时，它不起作用

But when I tried to move it in java (scala) code it doesn't work with

db.eval(scriptContent)

有人用DB.eval()方法成功吗?

Does anybody succeed with DB.eval() method?

推荐答案

eval() VS这样运行脚本

mongo 127.0.0.1:27017/dbName script.js

不相等. eval()发送要在mongod实例上执行的脚本，而该命令使用驱动程序访问数据库.

are not equivalent. eval() sends the script to be executed on a mongod instance, whereas the command uses the driver to access the db.

正如其他人所指出的，应避免使用eval()，因为它有很多缺点，例如，无法在分片环境中工作，或者不允许在后台创建索引.

As pointed out by others, eval() should be avoided as it has a lot of drawbacks, for instance, won't work on a sharded environment, or does not allow to create indexes in background.

哦！并回答这个问题，是的，我确实在Java中成功使用eval().但是，有些事情根本行不通;)

Oh! and to answer the question, yes I did succeed with eval() in java. However, there are things that will simply not work ;)

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