Think in java Stream 经典

核心提示：import java.io.*;public class NewIODemo {public static void main(String[] args) { try { // 1. Reading input by lines: BufferedReader in = new BufferedReader( ne

import java.io.*;

public class NewIODemo {public static void main(String[] args) { try {　 // 1. Reading input by lines:　 BufferedReader in =　 new BufferedReader(　 new FileReader(args[0]));　 String s, s2 = new String();　 while((s = in.readLine())!= null)　 s2 += s + "\n";　 in.close();　　// 1b. Reading standard input:　 BufferedReader stdin =　　new BufferedReader(　　 new InputStreamReader(System.in)); 　 System.out.PRint("Enter a line:");　 System.out.println(stdin.readLine());　　　// 2. Input from memory　 StringReader in2 = new StringReader(s2);　 int c;　 while((c = in2.read()) != -1)　　System.out.print((char)c);　　　// 3. Formatted memory input　 try {　　 DataInputStream in3 =　　 new DataInputStream(　　 // Oops: must use deprecated class:　　 new StringBufferInputStream(s2));　　 while(true)　　　System.out.print((char)in3.readByte());　 } catch(EOFException e) {　　　System.out.println("End of stream");　 }　　　// 4. Line numbering & file output　 try {　　 LineNumberReader li =　　　new LineNumberReader(　　　 new StringReader(s2));　　 BufferedReader in4 =　　　new BufferedReader(li);　　 PrintWriter out1 =　　　new PrintWriter(　　　 new BufferedWriter(　　　　new FileWriter("IODemo.out")));　　 while((s = in4.readLine()) != null )　　 out1.println(　　　"Line " + li.getLineNumber() + s);　　 out1.close();　 } catch(EOFException e) {　　 System.out.println("End of stream");　 }　　　// 5. Storing & recovering data　 try {　　 DataOutputStream out2 =　　 new DataOutputStream(　　　 new BufferedOutputStream(　　　　 new FileOutputStream("Data.txt")));　　 out2.writeDouble(3.14159);　　 out2.writeBytes("That was pi");　　 out2.close();　　 DataInputStream in5 =　　 new DataInputStream(　　　new BufferedInputStream(　　　 new FileInputStream("Data.txt")));　　 BufferedReader in5br =　　　 new BufferedReader(　　　　 new InputStreamReader(in5));　　 // Must use DataInputStream for data:　　 System.out.println(in5.readDouble());　　 // Can now use the "proper" readLine():　　 System.out.println(in5br.readLine());　 } catch(EOFException e) {　　 System.out.println("End of stream");　 }　　　// 6. Reading and writing random access　 // files is the same as before.　 // (not repeated here)　　　} catch(FileNotFoundException e) {　　 System.out.println(　　 "File Not Found:" + args[1]);　 } catch(IOException e) {　　 System.out.println("IO Exception");　 } }} ///:~