IO

字節流

InputStream      如 FileInputStream、ByteArrayInputStream

OutputStream   如 FileOutputStream、ByteArrayOutputStream

字符流

Reader   如 FileReader

Writer    如 FileWriter  可以用writer()直接寫出字符串

緩衝流

BufferedInputStream

BufferedOutputStream

BufferedReader  用readLine()讀整行

BufferedWriter   用newLine()可換行

轉換流

InputStreamReader

OutputStreamWriter 轉換後用write()可直接寫出字符串

數據流

DataInputStream

DataOutputStream

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FileInputStream：

import java.io.FileInputStream; import java.io.IOException; public class TestFileInputStream { public static void main(String[] args) throws IOException { int b = 0; FileInputStream in = new FileInputStream("d://java/***.java"); long num = 0; while ((b = in.read()) != -1) { System.out.println((char) b); num++; } in.close(); System.out.println(); System.out.println("共讀取了" + num + "個字節"); } }

 

FileOutputStream：

public class TestFileOutputStream { public static void main(String[] args) throws IOException { int b = 0; FileInputStream in = new FileInputStream("d://***.java"); FileOutputStream out = new FileOutputStream("e://***.java"); while ((b = in.read()) != -1) { out.write(b); } in.close(); out.close(); System.out.println("文件已複製"); } }

 

FileReader：

public class TestFileReader { public static void main(String[] args) throws IOException { FileReader fr = new FileReader("d://***.java"); int c = 0; while ((c = fr.read()) != -1) { System.out.print((char)c); } fr.close(); } }

 

BufferStream：

public class TestBufferStream { public static void main(String[] args) throws IOException { FileInputStream fis = new FileInputStream("d://***.java"); BufferedInputStream bis = new BufferedInputStream(fis); int c = 0; while ((c = bis.read()) != -1) { System.out.println((char) c); } fis.close(); bis.close(); } }

 

public class TestBufferStream { public static void main(String[] args) throws IOException { BufferedWriter bw = new BufferedWriter(new FileWriter("d://***.java")); BufferedReader br = new BufferedReader(new FileReader("d://***.java")); String str = null; for (int i = 0; i < 100; i++) { str = String.valueOf(Math.random()); bw.write(str); bw.newLine(); } bw.flush(); while ((str = br.readLine()) != null) { System.out.println(str); } bw.close(); br.close(); } }

 

TransForm：

public class TestTransForm { public static void main(String[] args) throws IOException { OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream( "d://***.java")); osw.write("fdfsdfsfdfsaaa"); System.out.println(osw.getEncoding()); osw.close(); osw = new OutputStreamWriter( new FileOutputStream("d://***.java", true), "ISO8859-1"); osw.write("fdfsdfsfdfsaaa"); System.out.println(osw.getEncoding()); osw.close(); } }

 

public class TestTransForm { public static void main(String[] args) throws IOException { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); String s = null; s = br.readLine(); while (s != null) { if (s.equalsIgnoreCase("exit")) break; System.out.println(s.toUpperCase()); s = br.readLine(); } br.close(); } }

 

DataStream：

public class TestDataStream { public static void main(String[] args) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); DataOutputStream dos = new DataOutputStream(baos); dos.writeDouble(Math.random()); dos.writeBoolean(true); ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray()); System.out.println(bais.available()); DataInputStream dis = new DataInputStream(bais); System.out.println(dis.readDouble()); System.out.println(dis.readBoolean()); dos.close(); dis.close(); } }