如何使用java生成带有随机数据的大型csv

Question

如何使用带有一些独特数据的 java 以 csv 格式生成百万行记录。

Answer 1

This can give you an idea of how to build a generator. The random data can be generated using Random class and adapting it to the data you need to generate.

public interface ICsvRandomRenerator{
  /* Adds the field definition to an array list that describes the csv */
  public void addFieldDefinition(FieldDefinition fieldDefinition);

  /* Runs a loop for the number of records needed and for each one it
     goes through the FieldDefinition ArrayList, generates the random
     data based on field definition, and adds it to the curret
     record. Last field changes to a new record*/

  public void generateFile(String fileName);
};

public class FieldDefinition(){
    String fieldName;
    String fieldType; //Alphabetic, Number, Date, etc..
    int length;
    <getters and setters>
}

public abstract class CsvRandomGenerator implements ICsvRandomGenerator{
    ArrayList<FieldDefinition> fields = new ArrayList<>();

    <@Override interface classes to implement them >.

    private String generateRandomAlpha();

    private String generateRandomDate();

    private String generateRandomNumber();

    ...
}

Answer 2

Check out this tutorial .

The code can be quite simple:

MockNeat m = MockNeat.threadLocal();
final Path path = Paths.get("./test.csv");

m.fmt("#{id},#{first},#{last},#{email},#{salary}")
 .param("id", m.longSeq())
 .param("first", m.names().first())
 .param("last", m.names().last())
 .param("email", m.emails())
 .param("salary", m.money().locale(GERMANY).range(2000, 5000))
 .list(1000)
 .consume(list -> {
            try { Files.write(path, list, CREATE, WRITE); }
            catch (IOException e) { e.printStackTrace(); }
 });

And the possible result is:

0,Ailene,Greener,auldsoutache@gmx.com,4.995,59 €
1,Yung,Skovira,sereglady@mail.com,2.850,23 €
2,Shanelle,Hevia,topslawton@mac.com,2.980,19 €
3,Venice,Lepe,sagelyshroud@mail.com,4.611,83 €
4,Mi,Repko,nonedings@email.com,3.811,38 €
5,Leonie,Slomski,plumpcreola@aol.com,4.584,28 €
6,Elisabeth,Blasl,swartjeni@mail.com,2.839,69 €
7,Ernestine,Syphard,prestoshod@aol.com,3.471,93 €
8,Honey,Winfrey,pseudpatria@email.com,4.276,56 €
9,Dian,Holecek,primbra@att.net,3.643,66 €
10,Mitchell,Lawer,lessjoellen@yahoo.com,3.260,92 €
11,Kayla,Labbee,hobnailmastella@mail.com,2.504,99 €
12,Jann,Grafenstein,douremile@verizon.net,4.535,70 €
13,Shaunna,Uknown,taughtclifton@gmx.com,3.028,81 €
...