学习内容

1.File中的核心方法

2.File中的方法实例

3.网络IO

4.执行shell方法

5.线程，同步关键字

屏幕快照 2020-12-29 下午9.03.20.png

package day1

import java.io.BufferedReader
import java.io.File
import java.io.InputStream
import java.io.InputStreamReader
import java.net.URL
import java.nio.charset.Charset
import kotlin.concurrent.thread

/**
 *
 * IO操作
 */
fun main(args:Array<String>){
    val path = ""
    val f1 = getFileContent(path)
    println("f1:"+f1)
    val f2 = getFileLines(path)
    println("f2:"+f2)
    val f3 = getByteArray(path)
    println("f3:"+f3)
    joinJava(path)
    writeFile("Hello world","file.data")
    appendFile("Kotlin java","file.data")
    travelFileTree("")
    println(getUrlHTML("https://www.baidu.com"))
    writeURLIntoFile("https://www.baidu.com","file.data")
    writeURLIntoFile("https://t7.baidu.com/it/u=3065092861,1536340632&fm=193&f=GIF",
            "1.jpg")
    testProcess()
    testThread()

}
@Volatile var running = false //kotlin没有volatile关键字
fun testThread(){
    object :Thread(){
        override fun run() {
            Thread.sleep(1000)
            println("A 使用Thread对象表达式：${Thread.currentThread()}")
        }
    }.start()
    Thread({
        Thread.sleep(1000)
        println("A 使用Thread对象表达式：${Thread.currentThread()}")
    }).start()
    val t = Thread({
        Thread.sleep(1000)
        println("A 使用Thread对象表达式：${Thread.currentThread()}")
    })
    t.isDaemon = false
    t.start()
    thread(start = true,isDaemon = false) {
        println("使用kotlin封装thread")
    }
}

fun testProcess(){
    val p = "ls -al".execute()
    val exitCode = p.waitFor()
    val text = p.text()
    println(exitCode)
    println(text)
}

fun Process.text():String{
    var output = ""
    val ins = this.inputStream
    val isr = InputStreamReader(ins)
    val reader = BufferedReader(isr)
    var line:String? = ""
    while (line!=null) {
        line = reader.readLine()
        output += line + "\n"
    }
    return output
}

fun String.execute():Process{
    val runtime = Runtime.getRuntime()
    return runtime.exec(this)
}

@Synchronized //同步标志
fun writeURLIntoFile(url: String,fileName: String){
    val byte = URL(url).readBytes()
    File(fileName).writeBytes(byte)
}

/**
 * 获取响应的字节数组
 */
fun getURLBytes(url: String):ByteArray{
    return URL(url).readBytes()
}

/**
 * 根据URL获取URL响应内容HTML
 */
fun getUrlHTML(url:String):String{
    return URL(url).readText(Charset.forName("UTF-8"))
}

fun getFileSequence(fileName: String,p:(File)->Boolean):Sequence<File>{
    val f = File(fileName)
    val fileWalk = f.walk()
    return fileWalk.filter(p)
}

fun getFileIterator(fileName: String):Iterator<File>{
    val f = File(fileName)
    val fileWalk = f.walk()
    return fileWalk.iterator()
}

fun travelFileTree(fileName: String){
    val f = File(fileName)
    val fileWalk = f.walk()
    fileWalk.iterator().forEach {
        println(it.absolutePath)
    }
}

fun appendFile(text:String, destFile:String){
    var f = File(destFile)
    if (!f.exists()) {
        f.createNewFile()
    }
    f.appendText(text, Charset.defaultCharset())
}

fun writeFile(text:String, destFile:String){
    var f = File(destFile)
    if (!f.exists()) {
        f.createNewFile()
    }
    f.writeText(text,Charset.defaultCharset())
}

fun getFileContent(fileName:String):String{
    var f = File(fileName)
    return f.readText(Charset.forName("UTF-8"))
}

fun getFileLines(fileName: String):List<String>{
    return File(fileName).readLines(Charset.forName("UTF-8"));
}

fun getByteArray(fileName: String):ByteArray{
    return File(fileName).readBytes();
}

fun joinJava(fileName: String){
    val reader = File(fileName).reader()
    val ins:InputStream = File(fileName).inputStream()
    val bfd :BufferedReader = File(fileName).bufferedReader()
}