为什么错误 "Uninitialized constant DriverManager" 出现在以前运行的代码中？

Question

我正在使用 jruby，我正在通过 db2jcc4.jar 文件调用 DB2/BIGSQL 数据库。我在插入和选择时都建立了完美的连接，然后突然间我开始收到错误 "uninitialized constant DriverManager."

文件 db2jcc4.jar 可读且具有正确的权限。我什至回到以前工作的代码的早期版本，我得到了同样的错误。唯一值得注意的变化是服务器重新启动了。

require 'java'

java_import 'com.ibm.db2.jcc.DB2Driver'
java_import 'java.util.Properties'

url = "jdbc:db2://SERVER-REMOVED:PORT_REMOVED/BIGSQL"
output, rset, stmt, conn = nil

begin
  properties = java.util.Properties.new
  properties['user'] = 'USER REMOVED'
  properties['password'] = 'PASSWORD REMOVED'

  # Load driver class
  driver = DB2Driver.new

  DriverManager.registerDriver driver #this comes out to nil
  regDrivers = DriverManager.getDrivers
  conn = DriverManager.get_connection url, properties
  ...

知道发生了什么吗？

Answer 1

您可能需要导入 DriverManager class

java_import 'java.sql.DriverManager'

为什么错误 "Uninitialized constant DriverManager" 出现在以前运行的代码中？

Why does the error "Uninitialized constant DriverManager" occur in previously functioning code?

ruby

java

jruby

jdbc

driver