java入门系列bufferwriter&reader

package reader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.util.Scanner;
import java.nio.charset.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;


public class reader {

  public static void  main(String[] avgs) throws IOException{
System.out.println("what is your name!");
Scanner in = new Scanner(System.in);
String username = in.next();
Greeter worldGreeter = new Greeter(username) ;
 String greeting = worldGreeter.sayHello();
in.close();

Path file =Paths.get(System.getProperty("user.home")).resolve("java").resolve("saying.txt");
 if(!Files.exists(file)){
 System.out.println(file+"  does not exist.terminating program");
      System.exit(1);
 }
 
try(BufferedWriter writer = new BufferedWriter(Files.newBufferedWriter(file,Charset.forName("gb2312")))){
writer.write(greeting);
}



try (BufferedReader filein= new BufferedReader(Files.newBufferedReader(file,Charset.forName("gb2312")))){
String saying =null ;
while((saying= filein.readLine())!=null){
System.out.println(saying);
}
}  

}

}

//Greeter.class

package reader;

public class Greeter {


public Greeter (String aName){
name = aName;
}
public String sayHello(){
return "hello,"+ name +"!";
}
private String name;
}

详细参考教程：http://blog.youkuaiyun.com/liuhenghui5201/article/details/8279557