mysql_jruby.rb

require './mysql-connector-java-5.1.47-bin.jar'

require "rubygems"
require "java"
require "csv"

    begin
      # Prep the connection
      Java::com.mysql.jdbc.Driver
      userurl = "jdbc:mysql://10.52.3.224:3306/market"
      connSelect = java.sql.DriverManager.get_connection(userurl, "username", "password(")
      stmtSelect = connSelect.create_statement

      # Define the query
      selectquery = %q{select u.uid as uid, u.email as email, f.asset_code as coin, f.amount_available as avai, f.amount_lock as lk, f.amount_loan as lon from user as u join finance as f on f.uid = u.uid}

      # Execute the query
      rsS = stmtSelect.execute_query(selectquery)
      # For each row returned do some stuff
      res = []
      while (rsS.next) do
        row = []
        row << rsS.getObject("uid")
        row << rsS.getObject("email")
        row << rsS.getObject("coin").to_s
        row << rsS.getObject("avai").to_s
        row << rsS.getObject("lk").to_s
        row << rsS.getObject("lon").to_s

        res.push(row)
      end

    File.write("/tmp/assets.csv", res.map(&:to_csv).join)

    end
    # Close off the connection
    stmtSelect.close
    connSelect.close
    return true


    # wget -c https://cdn.mysql.com//Downloads/Connector-J/mysql-connector-java-5.1.48.tar.gz
    # wget -c https://github.com/jruby/jruby/releases/download/9.2.11.0/jruby-dist-9.2.11.0-bin.tar.gz

jruby 有点好就是不需要安装， 开包即用