Archive

Posts Tagged ‘groovy’

Groovy blob and mysql

September 20th, 2009

In certain occasions e.g. when you want to save scrapped html page or just a specific part of it (e.g. div with its contents) the recommendation I found is to use the blob type and save xml document as binary stream.

In groovy, this is achieved in a rather simple way:

class Document {
  int id
  String title
  String xmlContent
}
 
Sql sql = Sql.newInstance(
          "jdbc:mysql://localhost:3306/documents_db?useUnicode=true&characterEncoding=UTF-8&useBlobToStoreUTF8OutsideBMP=true",
          "user", "pass", "com.mysql.jdbc.Driver")
 
// We assume db table similar to:
sql.execute("""
    CREATE TABLE IF NOT EXISTS `document` (
      `id` bigint(32) NOT NULL AUTO_INCREMENT,
      `title` varchar(500) NOT NULL,
      `xmlContent` blob,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    """)
 
def saveDocuments(def docs) {
  println "Saving documents to database..."
  def documents = sql.dataSet("document")
  docs.each {Document doc ->
    documents.add(title: doc.title, xmlContent: doc.xmlContent)
  }
}

When you want to retrieve data, with Groovy this is not much complicated either:

def loadDocuments() {
  def list = []
  sql.eachRow("SELECT * FROM document") {
    Document doc = new Document(it.toRowResult())
    if (it['xmlContent'] != null) {
      doc.xmlContent = new String(it['xmlContent'])
    }
    list.add(doc)
  }
  println "Loaded ${list.size()} documents from database"
  list
}

I tried the code with mysql database but I assume that you can achieve the same with any other database.

One hint for mysql blobs and utf-8: although utf-8 charset behaves very well with other database table fields (if you add useUnicode=true and characterEncoding=UTF-8 parameters to your connection string), in order to work with utf-8  blob fields you should adjust one more parameter: useBlobToStoreUTF8OutsideBMP=true. With this parameter set, your utf8 encoded xml documents will behave well with mysql database.

Share/Save/Bookmark

Java, groovy , , ,

Groovy meliorates and dries

June 12th, 2009


Dynamic languages are very popular at this time and you probably had insight into at least one of them (Ruby, Python, Groovy).

If you are bound to Java platform the best way to “be dynamic” IMHO is to work with Groovy.

Apart from the http://groovy.codehaus.org/ where you can find documentation, getting started examples etc. there are many blogs around that blog about groovy.

My favorite (although very slow) is Andres Almiray’s blog. He mostly blogs about griffon and groovy and has nice tutorials and examples. There I found info about many open source libraries I never heard of but which are quite useful, for example: FEST, Glazed list, Swing clarity, etc.

Try Groovy cause it’s groovy :)

I felt like when I run my first program at elementary school and it wrote “Ninja” on the screen :)

Share/Save/Bookmark

Java, groovy ,