{"id":134051,"date":"2020-07-21T06:21:25","date_gmt":"2020-07-20T22:21:25","guid":{"rendered":"http:\/\/4563.org\/?p=134051"},"modified":"2020-07-21T06:21:25","modified_gmt":"2020-07-20T22:21:25","slug":"scala%e8%af%ad%e8%a8%80%e5%ad%a6%e4%b9%a0%ef%bc%88%e5%8d%81%e4%b8%80%ef%bc%89%e3%80%81%e9%9a%90%e5%bc%8f%e8%bd%ac%e6%8d%a2%e5%92%8c%e9%9a%90%e5%bc%8f%e5%8f%82%e6%95%b0","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=134051","title":{"rendered":"scala\u8bed\u8a00\u5b66\u4e60\uff08\u5341\u4e00\uff09\u3001\u9690\u5f0f\u8f6c\u6362\u548c\u9690\u5f0f\u53c2\u6570"},"content":{"rendered":"

scala\u63d0\u4f9b\u7684\u9690\u5f0f\u8f6c\u6362\u548c\u9690\u5f0f\u53c2\u6570\u529f\u80fd\uff0c\u662f\u975e\u5e38\u6709\u7279\u8272\u7684\u529f\u80fd\u3002\u662fJava\u7b49\u7f16\u7a0b\u8bed\u8a00\u6240\u6ca1\u6709\u7684\u529f\u80fd\u3002\u5b83\u53ef\u4ee5\u5141\u8bb8\u4f60\u624b\u52a8\u6307\u5b9a\uff0c\u5c06\u67d0\u79cd\u7c7b\u578b\u7684\u5bf9\u8c61\u8f6c\u6362\u6210\u5176\u4ed6\u7c7b\u578b\u7684\u5bf9\u8c61\u6216\u8005\u662f\u7ed9\u4e00\u4e2a\u7c7b\u589e\u52a0\u65b9\u6cd5\u3002\u901a\u8fc7\u8fd9\u4e9b\u529f\u80fd\uff0c\u53ef\u4ee5\u5b9e\u73b0\u975e\u5e38\u5f3a\u5927\u3001\u7279\u6b8a\u7684\u529f\u80fd\u3002<\/p>\n

\u9690\u5f0f\u8f6c\u6362\u5176\u6838\u5fc3\u5c31\u662f\u5b9a\u4e49\u4e00\u4e2a\u4f7f\u7528 implicit<\/code> \u5173\u952e\u5b57\u4fee\u9970\u7684\u65b9\u6cd5\u5b9e\u73b0\u628a\u4e00\u4e2a\u539f\u59cb\u7c7b\u8f6c\u6362\u6210\u76ee\u6807\u7c7b\uff0c\u8fdb\u800c\u53ef\u4ee5\u8c03\u7528\u76ee\u6807\u7c7b\u4e2d\u7684\u65b9\u6cd5<\/p>\n

<\/a>\u9690\u5f0f\u53c2\u6570<\/h3>\n

\u6240\u8c13\u7684\u9690\u5f0f\u53c2\u6570\uff0c\u6307\u7684\u662f\u5728\u51fd\u6570\u6216\u8005\u65b9\u6cd5\u4e2d\uff0c\u5b9a\u4e49\u4e00\u4e2a\u7528implicit\u4fee\u9970\u7684\u53c2\u6570\uff0c
\u6b64\u65f6Scala\u4f1a\u5c1d\u8bd5\u627e\u5230\u4e00\u4e2a\u6307\u5b9a\u7c7b\u578b\u7684\u7528implicit\u4fee\u9970\u7684\u53c2\u6570\uff0c\u5373\u9690\u5f0f\u503c\uff0c\u5e76\u6ce8\u5165\u53c2\u6570\u3002<\/p>\n

\u6240\u6709\u7684\u9690\u5f0f\u8f6c\u6362\u548c\u9690\u5f0f\u53c2\u6570\u5fc5\u987b\u5b9a\u4e49\u5728\u4e00\u4e2aobject\u4e2d<\/p>\n

<\/a>\u8ba9File\u7c7b\u5177\u5907RichFile\u7c7b\u4e2d\u7684read\u65b9\u6cd5<\/h3>\n
\n\n\n
\n
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<\/pre>\n<\/td>\n
\n
<\/span>
package<\/span> com.kaikeba.implic_demo<\/span>
<\/span>
import<\/span> java.io.File<\/span><\/span>
<\/span>
import<\/span> scala.io.Source<\/span><\/span>
<\/span>
\/\/todo:\u9690\u5f0f\u8f6c\u6362\u6848\u4f8b\u4e00:\u8ba9File\u7c7b\u5177\u5907RichFile\u7c7b\u4e2d\u7684read\u65b9\u6cd5<\/span><\/span>
<\/span>
object<\/span> MyPredef<\/span><\/span>{<\/span>
  \/\/\u5b9a\u4e49\u4e00\u4e2a\u9690\u5f0f\u8f6c\u6362\u7684\u65b9\u6cd5\uff0c\u5b9e\u73b0\u628aFile\u8f6c\u6362\u6210RichFile<\/span><\/span>
  implicit<\/span>  def<\/span> file2RichFile<\/span><\/span>(file:File<\/span>)=new<\/span> RichFile<\/span>(file)<\/span>
<\/span>
}<\/span>
<\/span>
class<\/span> RichFile<\/span>(val file:File<\/span><\/span>)<\/span>{<\/span>
     \/\/\u8bfb\u53d6\u6570\u636e\u6587\u4ef6\u7684\u65b9\u6cd5<\/span><\/span>
    def<\/span> read<\/span><\/span>():String<\/span>={<\/span>
       Source<\/span>.fromFile(file).mkString<\/span>
    }<\/span>
}<\/span>
<\/span>
object<\/span> RichFile<\/span><\/span>{<\/span>
  def<\/span> main<\/span><\/span>(args: Array<\/span>[String<\/span>]): Unit<\/span> = {<\/span>
     \/\/1\u3001\u6784\u5efa\u4e00\u4e2aFile\u5bf9\u8c61<\/span><\/span>
          val<\/span> file = new<\/span> File<\/span>(\"E:\\aa.txt\"<\/span>)<\/span>
<\/span>
     \/\/2\u3001\u624b\u52a8\u5bfc\u5165\u9690\u5f0f\u8f6c\u6362<\/span><\/span>
      import<\/span> MyPredef<\/span>.file2RichFile<\/span>
<\/span>
       val<\/span> data: String<\/span> = file.read<\/span>
        println(data)<\/span>
  }<\/span>
}<\/span>
<\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/figure>\n
<\/a>\u8d85\u4eba\u53d8\u8eab<\/h3>\n
\n\n\n
\n
1<\/span>
2<\/span>
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<\/pre>\n<\/td>\n
\n
package<\/span> com.kaikeba.implic_demo<\/span>
<\/span>
\/\/todo:\u9690\u5f0f\u8f6c\u6362\u6848\u4f8b\u4e8c:\u8d85\u4eba\u53d8\u8eab<\/span><\/span>
class<\/span> Man<\/span>(val name:String<\/span><\/span>)<\/span><\/span>
<\/span><\/span>
class<\/span> SuperMan<\/span>(val name: String<\/span><\/span>) <\/span>{<\/span>
  def<\/span> heat=print<\/span><\/span>(\"\u8d85\u4eba\u6253\u602a\u517d\"<\/span>)<\/span>
<\/span>
}<\/span>
<\/span>
object<\/span> SuperMan<\/span><\/span>{<\/span>
  \/\/\u9690\u5f0f\u8f6c\u6362\u65b9\u6cd5<\/span><\/span>
  implicit<\/span> def<\/span> man2SuperMan<\/span><\/span>(man:Man<\/span>)=new<\/span> SuperMan<\/span>(man.name)<\/span>
<\/span>
  def<\/span> main<\/span><\/span>(args: Array<\/span>[String<\/span>]) {<\/span>
      val<\/span> hero=new<\/span> Man<\/span>(\"hero\"<\/span>)<\/span>
      \/\/Man\u5177\u5907\u4e86SuperMan\u7684\u65b9\u6cd5<\/span><\/span>
      hero.heat<\/span>
  }<\/span>
<\/span>
}<\/span>
<\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/figure>\n
<\/a>\u4e00\u4e2a\u7c7b\u9690\u5f0f\u8f6c\u6362\u6210\u5177\u6709\u76f8\u540c\u65b9\u6cd5\u7684\u591a\u4e2a\u7c7b<\/h3>\n
\n\n\n
\n
1<\/span>
2<\/span>
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<\/pre>\n<\/td>\n
\n
package com.kaikeba.implic_demo<\/span>
<\/span>
//todo:\u9690\u5f0f\u8f6c\u6362\u6848\u4f8b\u4e09\uff08\u4e00\u4e2a\u7c7b\u9690\u5f0f\u8f6c\u6362\u6210\u5177\u6709\u76f8\u540c\u65b9\u6cd5\u7684\u591a\u4e2a\u7c7b\uff09<\/span>
<\/span>
class C<\/span>
class A(c:C) {<\/span>
    def readBook(): Unit ={<\/span>
      println("A\u8bf4\uff1a\u597d\u4e66\u597d\u4e66...")<\/span>
    }<\/span>
}<\/span>
<\/span>
class B(c:C){<\/span>
  def readBook(): Unit ={<\/span>
    println("B\u8bf4\uff1a\u770b\u4e0d\u61c2...")<\/span>
  }<\/span>
  def writeBook(): Unit ={<\/span>
    println("B\u8bf4\uff1a\u4e0d\u4f1a\u5199...")<\/span>
  }<\/span>
}<\/span>
<\/span>
object AB{<\/span>
<\/span>
  //\u521b\u5efa\u4e00\u4e2a\u7c7b\u8f6c\u6362\u4e3a2\u4e2a\u7c7b\u7684\u9690\u5f0f\u8f6c\u6362<\/span>
  implicit def C2A(c:C)=new A(c)<\/span>
  implicit def C2B(c:C)=new B(c)<\/span>
}<\/span>
<\/span>
object B{<\/span>
  def main(args: Array[String]) {<\/span>
    //\u5bfc\u5305<\/span>
    //1. import AB._ \u4f1a\u5c06AB\u7c7b\u4e0b\u7684\u6240\u6709\u9690\u5f0f\u8f6c\u6362\u5bfc\u8fdb\u6765<\/span>
    //2. import AB.C2A \u53ea\u5bfc\u5165C\u7c7b\u5230A\u7c7b\u7684\u7684\u9690\u5f0f\u8f6c\u6362\u65b9\u6cd5<\/span>
    //3. import AB.C2B \u53ea\u5bfc\u5165C\u7c7b\u5230B\u7c7b\u7684\u7684\u9690\u5f0f\u8f6c\u6362\u65b9\u6cd5<\/span>
    import AB._<\/span>
    val c=new C<\/span>
<\/span>
    //\u7531\u4e8eA\u7c7b\u4e0eB\u7c7b\u4e2d\u90fd\u6709readBook()\uff0c\u53ea\u80fd\u5bfc\u5165\u5176\u4e2d\u4e00\u4e2a\uff0c\u5426\u5219\u8c03\u7528\u5171\u540c\u65b9\u6cd5\u65f6\u4ee3\u7801\u62a5\u9519<\/span>
     //c.readBook()<\/span>
<\/span>
    //C\u7c7b\u53ef\u4ee5\u6267\u884cB\u7c7b\u4e2d\u7684writeBook()<\/span>
    c.writeBook()<\/span>
<\/span>
  }<\/span>
}<\/span>
<\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/figure>\n
<\/a>\u5458\u5de5\u9886\u53d6\u85aa\u6c34<\/h3>\n
\n\n\n
\n
1<\/span>
2<\/span>
3<\/span>
4<\/span>
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<\/pre>\n<\/td>\n
\n
package<\/span> cn.itcast.implic_demo<\/span>
<\/span>
\/\/todo:\u9690\u5f0f\u53c2\u6570\u6848\u4f8b\u56db:\u5458\u5de5\u9886\u53d6\u85aa\u6c34<\/span><\/span>
<\/span>
object<\/span> Company<\/span><\/span>{<\/span>
  \/\/\u5728object\u4e2d\u5b9a\u4e49\u9690\u5f0f\u503c    \u6ce8\u610f\uff1a\u540c\u4e00\u7c7b\u578b\u7684\u9690\u5f0f\u503c\u53ea\u5141\u8bb8\u51fa\u73b0\u4e00\u6b21\uff0c\u5426\u5219\u4f1a\u62a5\u9519<\/span><\/span>
  implicit<\/span>  val<\/span> xxx=\"zhangsan\"<\/span><\/span>
  implicit<\/span>  val<\/span> yyy=10000.00<\/span><\/span>
<\/span>
  \/\/implicit  val zzz=\"lisi\"<\/span><\/span>
<\/span>
}<\/span>
<\/span>
class<\/span> Boss<\/span> <\/span>{<\/span>
  \/\/\u5b9a\u4e49\u4e00\u4e2a\u7528implicit\u4fee\u9970\u7684\u53c2\u6570 \u7c7b\u578b\u4e3aString<\/span><\/span>
  \/\/\u6ce8\u610f\u53c2\u6570\u5339\u914d\u7684\u7c7b\u578b   \u5b83\u9700\u8981\u7684\u662fString\u7c7b\u578b\u7684\u9690\u5f0f\u503c<\/span><\/span>
  def<\/span> callName<\/span><\/span>(implicit<\/span> name:String<\/span>):String<\/span>={<\/span>
    name+\" is coming !\"<\/span><\/span>
  }<\/span>
<\/span>
  \/\/\u5b9a\u4e49\u4e00\u4e2a\u7528implicit\u4fee\u9970\u7684\u53c2\u6570\uff0c\u7c7b\u578b\u4e3aDouble<\/span><\/span>
  \/\/\u6ce8\u610f\u53c2\u6570\u5339\u914d\u7684\u7c7b\u578b    \u5b83\u9700\u8981\u7684\u662fDouble\u7c7b\u578b\u7684\u9690\u5f0f\u503c<\/span><\/span>
  def<\/span> getMoney<\/span><\/span>(implicit<\/span> money:Double<\/span>):String<\/span>={<\/span>
    \" \u5f53\u6708\u85aa\u6c34\uff1a\"<\/span>+money<\/span>
  }<\/span>
<\/span>
<\/span>
}<\/span>
<\/span>
object<\/span> Boss<\/span> extends<\/span> App<\/span><\/span>{<\/span>
  \/\/\u4f7f\u7528import\u5bfc\u5165\u5b9a\u4e49\u597d\u7684\u9690\u5f0f\u503c\uff0c\u6ce8\u610f\uff1a\u5fc5\u987b\u5148\u52a0\u8f7d\u5426\u5219\u4f1a\u62a5\u9519<\/span><\/span>
  import<\/span> Company<\/span>.xxx<\/span>
  import<\/span> Company<\/span>.yyy<\/span>
<\/span>
  val<\/span> boss =new<\/span> Boss<\/span><\/span>
  println(boss.callName+boss.getMoney)<\/span>
<\/span>
}<\/span>
<\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/figure>\n","protected":false},"excerpt":{"rendered":"
scala\u63d0\u4f9b\u7684\u9690\u5f0f\u8f6c\u6362\u548c\u9690\u5f0f\u53c2\u6570…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/134051"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=134051"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/134051\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=134051"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=134051"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=134051"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}