【47】kotlin IO操作

File Stream Reader Writer的扩展方法

使用use扩展关闭资源

小文件，一次性读写操作

java code

package com.yzdzy.kotlin.chapter8.io;

import java.io.*;

public class IO {
    public static void main(String[] args) {
        BufferedReader bufferedReader = null;
        try {
            bufferedReader=new BufferedReader(new FileReader(new File("build.gradle")));
            String line;
            while ((line=bufferedReader.readLine())!=null){
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

kt

package com.yzdzy.kotlin.chapter8.io

import java.io.BufferedReader
import java.io.File
import java.io.FileReader

fun main(args: Array<String>) {
    val file = File("Build.gradle")
    val bufferedReader = BufferedReader(FileReader(file))
    var line: String
    while (true) {
        line = bufferedReader.readLine() ?: break
        println(line)
    }
    bufferedReader.close()
    ktIoForUse()
    ktIoForReadLines()


}
fun ktIoForUse(){
    val file = File("Build.gradle")
    BufferedReader(FileReader(file)).use{
        var line:String
        while (true){
            line=it.readLine()?:break
            println(line)
        }
    }

}
fun ktIoForReadLines(){
    val file = File("Build.gradle")
    file.readLines().forEach(::println)
}