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8. misc

8.1. xml

8.1.1. 生成

Scala原生支持xml，就如同Java支持String一样，这就让生成xml和xhtml很简单优雅：

val name = "james"

val age = 10

val html = name={name}, age="{age}" toString

// name=james, age="10"

又如：

val html = <title>{myTitle}</title>{"hello world"}

更复杂的例子：

val x = {(1 to 5).map(i => {i})}

// 12345

val x0 =

val {u} = x0 // u: scala.xml.Node =

8.1.2. xml文件

xml.XML loadString "

"

xml.XML loadFile "abc.xml"

xml.XML.saveFull("foo.xml", node, "UTF-8", xmlDecl: Boolean, doctype : DocType)

8.1.3. 读取：

val x = {(1 to 5).map(i => {i})}

// 12345

(x \ "e") map (_.text.toInt) // List(1, 2, 3, 4, 5)

val x0 =

20

30

(x0 \ "user") // 20, 30)

(x0 \ "user" \ "age") // (20, 30)

(x0 \ "age") // 直接下级: ()

(x0 \ "age") // 所有下级：(20, 30)

(x0 \ "_") 所有

8.1.4. 访问属性

val x =

(x \ "u" \ "@name") foreach println // "qh\njames\nqiu"

例子：

val data =

<shopping>
  <item name="bread" quantity="3" price="2.50"/>
  <item name="milk" quantity="2" price="3.50"/>
</shopping>

val res = for (item <- data \ "item" ; 
                 price = (item \ "@price").text.toDouble ; 
                 qty = (item \ "@quantity").text.toInt)
           yield (price * qty)

printf("$%.2f\n", res.sum)

8.1.5. 格式化输出

val pp = new xml.PrettyPrinter(80, 4) // 行宽 80，缩进为 4

pp formatNodes

结果是字符串

<a></a>

8.2. json

Scala-json

8.3. Configgy

http://www.lag.net/configgy/

简单配置及logging：

log {

filename = "/var/log/pingd.log"

roll = "daily"

level = "debug"

}

hostname = "pingd.example.com"

port = 3000

val conf = net.lag.configgy.Configgy.configure("/etc/pingd.conf").config

val hostname = conf.getString("hostname", "localhost")

val port = conf.getInt("port", 3000)

8.4. 正则表达式regex

例子1：完全匹配

//将字符串转为scala.util.matching.Regex

val pattern = "^[a-z0-9._%\-+]+@(?:[a-z0-9\-]+\.)+[a-z]{2,4}$"

val emailRegex = pattern.r // 或者 new scala.util.matching.Regex(pattern)

//emailRegex.pattern=>java.util.regex.Pattern 使用java的Pattern

emailRegex.pattern.matcher("tt@16.cn").matches // true

例子2：查找匹配部分

val p = "[0-9]+".r

p.findAllIn("2 ad 12ab ab21 23").toList // List(2, 12, 21, 23)

p.findFirstMatchIn("abc123xyz").get // scala.util.matching.Regex.Match = 123

更多例子如下：

定义：

val r1 = "(\d+) lines".r // syntactic sugar

val r2 = """(\d+) lines""".r // using triple-quotes to preserve backslashes

或者

import scala.util.matching.Regex

val r3 = new Regex("(\d+) lines") // standard

val r4 = new Regex("""(\d+) lines""", "lines") // with named groups

search和replace（java.lang.String的方法）：

"99 lines" matches "(\d+) lines" // true

"99 Lines" matches "(\d+) lines" // false

"99 lines" replace ("99", "98") // "98 lines"

"99 lines lines" replaceAll ("l", "L") // 99 Lines Lines

search（regex的方法）：


"\\d+".r findFirstIn "99 lines" // Some(99)
"\\w+".r findAllIn "99 lines" // iterator(长度为2)
"\\s+".r findPrefixOf "99 lines" // None
"\\s+".r findPrefixOf "  99 lines" // Some(  )
val r4 = new Regex("""(\d+) lines""", "g1") // with named groups
r4 findFirstMatchIn "99 lines-a" // Some(99 lines)
r4 findPrefixMatchOf "99 lines-a" // Some(99 lines)
val b = (r4 findFirstMatchIn "99 lines").get.group("g1") // "99"

match（regex的方法）：


val r1 = "(\\d+) lines".r
val r4 = new Regex("""(\d+) lines""", "g1")
val Some(b) = r4 findPrefixOf "99 lines" // "99 lines"

for {

  line <- """|99 lines-a

             |99 lines

             |pass

             |98 lines-c""".stripMargin.lines

} line match {

  case r1(n) => println("Has " + n + " Lines.") // "Has 99 Lines."
  case _ =>

}
 
for (matched <- "(\\w+)".r findAllIn "99 lines" matchData)

  println("Matched from " + matched.start + " to " + matched.end)

输出：

Matched from 0 to 2

Matched from 3 to 8

replace（regex的方法）：


val r2 = """(\d+) lines""".r  // using triple-quotes to preserve backslashes

r2 replaceFirstIn ("99 lines-a", "aaa") // "aaa-a"

r2 replaceAllIn ("99 lines-a, 98 lines-b", "bbb") // "bbb-a, bbb-b"

其他：使用正则表达式定义变量


val regex = "(\\d+)/(\\d+)/(\\d+)".r

val regex(year, month, day) = "2010/1/13"

// year: String = 2010

// month: String = 1

// day: String = 13

8.5. GUI

8.5.1. java方式

import javax.swing.JFrame

var jf = new JFrame("Hello!")

jf.setSize(800, 600)

jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)

jf.setVisible(true)

8.5.2. scala方式

import swing., swing.Swing.

object Swing1 extends SimpleGUIApplication { // scala2.7


  def top = new MainFrame { // 必须实现top方法

    title = "窗口1"

    preferredSize = (400, 300)

   

    val label = new Label("hello world cn中文")

    contents = new BorderPanel {

      layout(label) = BorderPanel.Position.Center

    }

  }

}