Java中的BufferedInputStream与BufferedOutputStream使用示例

BufferedInputStream(InputStream in)
BufferedInputStream(InputStream in, int size)

synchronized int   available()
void   close()
synchronized void   mark(int readlimit)
boolean   markSupported()
synchronized int   read()
synchronized int   read(byte[] buffer, int offset, int byteCount)
synchronized void   reset()
synchronized long   skip(long byteCount)

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.lang.SecurityException;

/**
 * BufferedInputStream 测试程序
 *
 * @author skywang
 */
public class BufferedInputStreamTest {

  private static final int LEN = 5;

  public static void main(String[] args) {
    testBufferedInputStream() ;
  }

  /**
   * BufferedInputStream的API测试函数
   */
  private static void testBufferedInputStream() {

    // 创建BufferedInputStream字节流，内容是ArrayLetters数组
    try {
      File file = new File("bufferedinputstream.txt");
      InputStream in =
         new BufferedInputStream(
           new FileInputStream(file), 512);

      // 从字节流中读取5个字节。“abcde”，a对应0x61，b对应0x62，依次类推...
      for (int i=0; i<LEN; i++) {
        // 若能继续读取下一个字节，则读取下一个字节
        if (in.available() >= 0) {
          // 读取“字节流的下一个字节”
          int tmp = in.read();
          System.out.printf("%d : 0x%s\n", i, Integer.toHexString(tmp));
        }
      }

      // 若“该字节流”不支持标记功能，则直接退出
      if (!in.markSupported()) {
        System.out.println("make not supported!");
        return ;
      }

      // 标记“当前索引位置”，即标记第6个位置的元素--“f”
      // 1024对应marklimit
      in.mark(1024);

      // 跳过22个字节。
      in.skip(22);

      // 读取5个字节
      byte[] buf = new byte[LEN];
      in.read(buf, 0, LEN);
      // 将buf转换为String字符串。
      String str1 = new String(buf);
      System.out.printf("str1=%s\n", str1);

      // 重置“输入流的索引”为mark()所标记的位置，即重置到“f”处。
      in.reset();
      // 从“重置后的字节流”中读取5个字节到buf中。即读取“fghij”
      in.read(buf, 0, LEN);
      // 将buf转换为String字符串。
      String str2 = new String(buf);
      System.out.printf("str2=%s\n", str2);

      in.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (SecurityException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

abcdefghijklmnopqrstuvwxyz
0123456789
ABCDEFGHIJKLMNOPQRSTUVWXYZ

0 : 0x61
1 : 0x62
2 : 0x63
3 : 0x64
4 : 0x65
str1=01234
str2=fghij

BufferedOutputStream(OutputStream out)
BufferedOutputStream(OutputStream out, int size)

synchronized void   close()
synchronized void   flush()
synchronized void   write(byte[] buffer, int offset, int length)
synchronized void   write(int oneByte)

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import java.lang.SecurityException;
import java.util.Scanner;

/**
 * BufferedOutputStream 测试程序
 *
 * @author skywang
 */
public class BufferedOutputStreamTest {

  private static final int LEN = 5;
  // 对应英文字母“abcddefghijklmnopqrsttuvwxyz”
  private static final byte[] ArrayLetters = {
    0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A
  };

  public static void main(String[] args) {
    testBufferedOutputStream() ;
  }

  /**
   * BufferedOutputStream的API测试函数
   */
  private static void testBufferedOutputStream() {

    // 创建“文件输出流”对应的BufferedOutputStream
    // 它对应缓冲区的大小是16，即缓冲区的数据>=16时，会自动将缓冲区的内容写入到输出流。
    try {
      File file = new File("out.txt");
      OutputStream out =
         new BufferedOutputStream(
           new FileOutputStream(file), 16);

      // 将ArrayLetters数组的前10个字节写入到输出流中
      out.write(ArrayLetters, 0, 10);
      // 将“换行符\n”写入到输出流中
      out.write('\n');

      // TODO!
      //out.flush();

      readUserInput() ;

      out.close();
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (SecurityException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * 读取用户输入
   */
  private static void readUserInput() {
    System.out.println("please input a text:");
    Scanner reader=new Scanner(System.in);
    // 等待一个输入
    String str = reader.next();
    System.out.printf("the input is : %s\n", str);
  }
}

out.write(ArrayLetters, 0, 10);

out.write(ArrayLetters, 0, 20);