// 读取输入的数据,直到数据中有Q这个字母然
            package IO; 
         import java.io.*; 
         public class IOStreamExample { 
      public static void main(String[] args) throws IOException { 
      // 1. 读入一行数据:
      BufferedReader in = new BufferedReader(new FileReader( 
      "FileStdRead.java")); 
      String s, s2 = new String(); 
      while ((s = in.readLine()) != null) { 
      s2 += s + ""; 
      } 
      in.close(); 
      BufferedReader stdin = new BufferedReader(new InputStreamReader( 
      System.in)); 
      System.out.print("Enter a line:"); 
      System.out.println(stdin.readLine()); 
      // 2. 从内存中读入
      StringReader in2 = new StringReader(s2); 
      int c; 
      while ((c = in2.read()) != -1) { 
      System.out.print((char) c); 
      } 
      // 3. 格式化内存输入
      try { 
      DataInputStream in3 = new DataInputStream(new ByteArrayInputStream( 
      s2.getBytes())); 
      while (true) { 
      System.out.print((char) in3.readByte()); 
      } 
      } catch (EOFException e) { 
      System.err.println("End of stream"); 
      } 
      // 4. 文件输入
      try { 
      BufferedReader in4 = new BufferedReader(new StringReader(s2)); 
      PrintWriter out1 = new PrintWriter(new BufferedWriter( 
      new FileWriter("IODemo.out"))); 
      int lineCount = 1; 
      while ((s = in4.readLine()) != null) { 
      out1.println(lineCount++ + ": " + s); 
      } 
      out1.close(); 
      } catch (EOFException e) { 
      System.err.println("End of stream"); 
      } 
      // 5. 接收和保存数据
      try { 
      DataOutputStream out2 = new DataOutputStream( 
      new BufferedOutputStream(new FileOutputStream("Data.txt"))); 
      out2.writeDouble(3.14159); 
      out2.writeUTF("That was pi"); 
      out2.writeDouble(1.41413); 
      out2.writeUTF("Square root of 2"); 
      out2.close(); 
      DataInputStream in5 = new DataInputStream(new BufferedInputStream( 
      new FileInputStream("Data.txt"))); 
         System.out.println(in5.readDouble()); 
         System.out.println(in5.readUTF()); 
      System.out.println(in5.readDouble()); 
      System.out.println(in5.readUTF()); 
      } catch (EOFException e) { 
      throw new RuntimeException(e); 
      } 
      // 6. 随机读取文件内容
      RandomAccessFile rf = new RandomAccessFile("rtest.dat", "rw"); 
      for (int i = 0; i < 10; i++) { 
      rf.writeDouble(i * 1.414); 
      } 
      rf.close(); 
      rf = new RandomAccessFile("rtest.dat", "rw"); 
      rf.seek(5 * 8); 
      rf.writeDouble(47.0001); 
      rf.close(); 
      rf = new RandomAccessFile("rtest.dat", "r"); 
      for (int i = 0; i < 10; i++) { 
      System.out.println("Value " + i + ": " + rf.readDouble()); 
      } 
      rf.close();
      } 
      }