JAVA中常用IO流类：FileInputStream和FileOutputStream

野性酷女 2022-06-07 10:26 199阅读 0赞

FileInputStream 用于读取本地文件中的字节数据，继承自InputStream类

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 <th colspan="2" align="left" style="">方法摘要</th> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;int</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#available%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">available</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;返回下一次对此输入流调用的方法可以不受阻塞地从此输入流读取（或跳过）的估计剩余字节数。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#close%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">close</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;关闭此文件输入流并释放与此流有关的所有系统资源。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">protected &nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#finalize%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">finalize</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;确保在不再引用文件输入流时调用其<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">close</code>&nbsp;方法。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;<a title="java.nio.channels 中的类" href="http://write.blog.csdn.net/java/nio/channels/FileChannel.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow">FileChannel</a></code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#getChannel%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">getChannel</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;返回与此文件输入流有关的唯一<a title="java.nio.channels 中的类" href="http://write.blog.csdn.net/java/nio/channels/FileChannel.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow"><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">FileChannel</code></a>&nbsp;对象。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;<a title="java.io 中的类" href="http://write.blog.csdn.net/java/io/FileDescriptor.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow">FileDescriptor</a></code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#getFD%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">getFD</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;返回表示到文件系统中实际文件的连接的&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">FileDescriptor</code>&nbsp;对象，该文件系统正被此<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">FileInputStream</code>&nbsp;使用。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;int</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#read%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">read</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;从此输入流中读取一个数据字节。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;int</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#read%28byte[]%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">read</a>(byte[]&nbsp;b)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;从此输入流中将最多&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">b.length</code>&nbsp;个字节的数据读入一个 byte 数组中。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;int</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#read%28byte[],%20int,%20int%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">read</a>(byte[]&nbsp;b, int&nbsp;off, int&nbsp;len)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;从此输入流中将最多&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">len</code>&nbsp;个字节的数据读入一个 byte 数组中。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;long</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileInputStream.html#skip%28long%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">skip</a>(long&nbsp;n)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;从输入流中跳过并丢弃&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">n</code>&nbsp;个字节的数据。</td> 
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其中`read()`返回的是读入的一个字节所对应的int值(0-255),而`read(byte[] b)`和`read(byte[] b, int off, int len)` 返回的是读入的字节数

FileOutputStream用于将字节数据写出到文件。继承自OutputStream类

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 <th colspan="2" align="left" style="">方法摘要</th> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#close%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">close</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;关闭此文件输出流并释放与此流有关的所有系统资源。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">protected &nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#finalize%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">finalize</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;清理到文件的连接，并确保在不再引用此文件输出流时调用此流的&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">close</code>&nbsp;方法。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;<a title="java.nio.channels 中的类" href="http://write.blog.csdn.net/java/nio/channels/FileChannel.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow">FileChannel</a></code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#getChannel%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">getChannel</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;返回与此文件输出流有关的唯一<a title="java.nio.channels 中的类" href="http://write.blog.csdn.net/java/nio/channels/FileChannel.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow"><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">FileChannel</code></a>&nbsp;对象。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;<a title="java.io 中的类" href="http://write.blog.csdn.net/java/io/FileDescriptor.html" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; outline:none; background:transparent" rel="nofollow">FileDescriptor</a></code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#getFD%28%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">getFD</a>()</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;返回与此流有关的文件描述符。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#write%28byte[]%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">write</a>(byte[]&nbsp;b)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;将&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">b.length</code>&nbsp;个字节从指定 byte 数组写入此文件输出流中。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#write%28byte[],%20int,%20int%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">write</a>(byte[]&nbsp;b, int&nbsp;off, int&nbsp;len)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;将指定 byte 数组中从偏移量&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">off</code>&nbsp;开始的&nbsp;<code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">len</code>&nbsp;个字节写入此文件输出流。</td> 
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 <td align="right" style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)">&nbsp;void</code></td> 
 <td style=""><code style="font-family:Monaco,Menlo,Consolas,'Courier New',monospace; font-size:14.4px; padding:2px 4px; color:rgb(199,37,78); white-space:nowrap; background-color:rgb(249,242,244)"><a href="http://write.blog.csdn.net/java/io/FileOutputStream.html#write%28int%29" style="color:rgb(202,12,22); text-decoration:none; margin:0px; padding:0px; font-weight:normal; outline:none; background:transparent" rel="nofollow">write</a>(int&nbsp;b)</code>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;将指定字节写入此文件输出流。</td> 
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实例代码：使用这两个类进行文件复制：

\[java\]  [view plain][]  [copy][view plain]

1.  **import** java.io.FileInputStream;  
2.  **import** java.io.FileOutputStream;  
3.  **import** java.io.IOException;  
4.  **class** IODemo  
5.  \{  
6.      **public** **static** **void** main(String\[\] args)   
7.      \{  
8.          **try**  
9.          \{  
10.         //使用FileInputStream和FileOutputStream进行文件复制  
11.         FileInputStream fis=**new** FileInputStream("a.txt");  
12.         FileOutputStream fos=**new** FileOutputStream("b.txt");  
13.             **int** read;  
14.             //read=fis.read();  
15.             **byte** b\[\]=**new** **byte**\[1024\];  
16.             //读取文件，存入字节数组b，返回读取到的字符数，存入read,默认每次将b数组装满  
17.             read=fis.read(b);  
18.             **while**(read!=-1)  
19.             \{  
20.                 fos.write(b,0,read);  
21.                 read=fis.read(b);  
22.                 //read=fis.read();  
23.             \}  
24.             fis.close();  
25.             fos.close();  
26.         \}  
27.         **catch** (IOException e)  
28.         \{  
29.             e.printStackTrace();  
30.         \}  
31.           
32.     \}  
33. \}

上述的例子采用也可以只使用对象fis的read()方法，逐个字节的读入数据，然后用对象fos的write()这个字节输出。

注：FileInputStream 和FileOutputStream适用于操作于任何形式的文件（因为是以字节为向导），如果想要操作文本文件，采用FileInputReader和FileOutputWriter效率更高。

[view plain]: http://blog.csdn.net/caixiexin/article/details/6719407#