Javase-I/O

 1 import java.io.ByteArrayInputStream;
 2 import java.io.ByteArrayOutputStream;
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.FileNotFoundException;
 6 import java.io.FileOutputStream;
 7 import java.io.FileReader;
 8 import java.io.IOException;
 9 import java.io.RandomAccessFile;
10 import java.io.StringBufferInputStream;
11 
12 
13 public class FileStream {
14 
15     public static void main(String[] args) throws IOException
16     {
17         //测试FileInputStream,FileOutputStream
18         FileInputStream fis = new FileInputStream("file.txt");
19         FileOutputStream fos = new FileOutputStream("file1.txt");
20         
21         byte[] bytes = new byte[fis.available()];
22         
23         fis.read(bytes);
24         fos.write(bytes);
25         
26         String s;
27         s = new String(bytes);
28         System.out.println(s);
29         
30     }
31 
32 }

 1 import java.io.ByteArrayInputStream;
 2 import java.io.ByteArrayOutputStream;
 3 
 4 
 5 public class ByteStreamTest {
 6 
 7     public static void main(String args[])
 8     {
 9         //测试ByteArrayOutputStream
10         ByteArrayOutputStream baos = new ByteArrayOutputStream();
11         //289截断到一个字节后二进制为0000 0033，对应的ascii字符为‘!‘
12         //原型为write(int),将289写入到字节数组
13         baos.write(289);
14         
15         byte[] b = baos.toByteArray();
16         System.out.println(b.length);
17         //这里字节又被强转为两个字节的char类型，二进制为0000 0000 0000 0033
18         System.out.println((char)b[0]);
19         
20         ByteArrayInputStream bais = new ByteArrayInputStream(b);
21         //这里read()将1个字节0000 0033转为整型返回，之后又强转为char
22         char c = (char) bais.read();
23         System.out.println(c);
24     }
25 }

1
!
!

 1 import java.io.FileReader;
 2 import java.io.FileWriter;
 3 import java.io.IOException;
 4 
 5 
 6 public class FileReaderWriterTest {
 7     public static void main(String args[]) throws IOException
 8     {
 9         FileReader fr = new FileReader("file.txt");
10         char[] s1 = new char[100];
11         //按字符也就是两个字节读入到字节数组
12         fr.read(s1);
13         for (int i = 0; i < s1.length; i++)
14             System.out.print(s1[i]);
15 
16         
17         char[] s2 = {‘你‘, ‘好‘};
18         FileWriter fw = new FileWriter("fileTo.txt");
19         //将字符数组写入到文件
20         fw.write(s2);
21         
22         //关闭文件，刷新缓冲区
23         fw.close();
24         fr.close();
25 
26         
27      }
28 
29 }

 1 import java.io.CharArrayReader;
 2 import java.io.CharArrayWriter;
 3 import java.io.IOException;
 4 
 5 
 6 public class CharArrayReaderWriterTest {
 7 
 8     public static void main(String[] args) throws IOException
 9     {
10         CharArrayWriter caw = new CharArrayWriter();
11         
12         char[] c = {‘字‘, ‘符‘, ‘数‘, ‘组‘};
13         //将字符数组写入缓冲区
14         caw.write(c);
15         //获取字符数组
16         char[] cc = caw.toCharArray();
17         String s = new String(cc);
18         System.out.println(s);
19         
20         //使用字符数组c构造CharArrayReader
21         CharArrayReader car = new CharArrayReader(c);
22         int a;
23         //读取每个字符
24         while ( (a = car.read()) != -1)
25         {
26             System.out.println((char)a);
27         }
28         
29     }
30 }

字符数组
字
符
数
组

 1 public class BufferedStream {
 2 
 3     public static void main(String args[]) throws IOException
 4     {
 5         //修饰流，需要由InputStream,OutputStream构造,本质上还是按字节读入写出，但是增加了缓冲
 6         BufferedInputStream bis = new BufferedInputStream(new FileInputStream("file.txt"));
 7         BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("fileTo.txt"));
 8         
 9         int bytesCount = 0;
10         int a;
11         while ( (a = bis.read()) != -1)
12         {
13             bytesCount++;
14             bos.write(a);
15         }
16         System.out.println("读取的字节数:"+bytesCount);
17         
18         
19         //记得关闭流，刷新缓冲区
20         bis.close();
21         bos.close();
22     }
23 }

 1 import java.io.BufferedReader;
 2 import java.io.BufferedWriter;
 3 import java.io.FileReader;
 4 import java.io.FileWriter;
 5 import java.io.IOException;
 6 
 7 
 8 public class BufferedReadWriterTest {
 9 
10     public static void main(String args[]) throws IOException
11     {
12         BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"));
13         BufferedReader br = new BufferedReader(new FileReader("file.txt"));
14         
15         bw.write("第一行\n");
16         bw.write("第二行\n");
17         bw.write("第三行\n");
18         bw.flush();
19         
20         
21         String s;
22         while ( (s = br.readLine()) != null)
23         {
24             System.out.println(s);
25         }
26         
27         br.close();
28         bw.close();
29         
30 
31         
32     }
33 }

第一行
第二行
第三行