io的一些知识

流分为节点流和处理流
节点流是直接读到数据上
节点流有 FileInputStream/FileReader 输出流FileOutputStream（字节流）/FileWriter（字符流 可以输出一个汉字）
        字符流：FileReader fr = new FileReader("d:/java/io/TestFileWriter2.java");
FileWriter fw = new FileWriter("d:/java/io/TestFileWriter2.bak");
int b;
while((b = fr.read()) != -1) {
fw.write(b);
}
fr.close();
fw.close();
       字节流：int b = 0;
  FileInputStream in = null;
  FileOutputStream out = null;
  try {
    in = new FileInputStream("d:/share/java/HelloWorld.java");
    out = new FileOutputStream("d:/share/java/io/HW.java");
    while((b=in.read())!=-1){
      out.write(b);
    }
    in.close();
    out.close();
处理流处理节点流的流
主要有 BufferedInputStream、BufferedReader
      例如：BufferedWriter bw = new BufferedWriter(new FileWriter("d:\\share\\java\\dat2.txt"));
      BufferedReader br = new BufferedReader(
             new FileReader("d:\\share\\java\\dat2.txt"));
      String s = null;
      for(int i=1;i<=100;i++){
        s = String.valueOf(Math.random());
        bw.write(s);
        bw.newLine();
      }
      bw.flush();
      while((s=br.readLine())!=null){
        System.out.println(s);
      }
      bw.close();
      br.close();

      BufferedInputStream例子：FileInputStream fis =
              new FileInputStream("d:\\share\\java\\HelloWorld.java");
      BufferedInputStream bis =
              new BufferedInputStream(fis);
      int c = 0;
      System.out.println(bis.read());
      System.out.println(bis.read());
      bis.mark(100);
      for(int i=0;i<=10 && (c=bis.read())!=-1;i++){
        System.out.print((char)c+" ");
      }
      System.out.println();
      bis.reset();
      for(int i=0;i<=10 && (c=bis.read())!=-1;i++){
        System.out.print((char)c+" ");
      }
      bis.close();