Java IO详解

一、按操作方式分

Reader-字符读取

• 节点流
  • FileReader
  • PipedReader
  • CharArrayReader
• 处理流
  • BufferedReader 
  • InputStreamReader 

Writer-字符写出

• 节点流
  • FileWriter
  • PipedWriter
  • CharArrayWriter
• 处理流
  • BufferedWriter 
  • OutputStreamWriter 
  • PrintWriter

InputStream-字节读取

• 节点流
  • FileInputStream
  • PipedInputStream
  • ByteArrayInputStream
• 处理流
  • BufferedInputStream 
  • DataInputStream 
  • ObjectInputStream 
  • SequenceInputStream

OutputStream-字节写出

• 节点流
  • FileOutputStream
  • PipedOutputStream
  • ByteArrayOutputStream
• 处理流
  • BufferedOutputStream 
  • DataOutputStream 
  • ObjectOutputStream
  • PrintStream

节点流：可以从或向一个特定的地方（节点）读写数据。
处理流：是对一个已存在的流的连接和封装，通过所封装的流的功能调用实现数据读写。

二、按操作对象分类

缓冲操作：BufferedReader BufferedWriter BufferedInputStream BufferedOutputStream 
基本数据类型操作：DataInputStream DataOutputStream 
对象序列化操作：ObjectInputStream ObjectOutputStream
转化控制：InputStreamReader OutputStreamWriter 
打印控制：PrintWriter PrintStream
文件操作：FileReader FileWriter FileInputStream FileInputStream
管道操作：PipedReader PipedWriter PipedInputStream PipedOutputStream
数组操作：ByteArrayInputStream ByteArrayOutputStream CharArrayWriter  CharArrayReader

个人遇到最常用的场景，就是文件处理了：

1.普通文件复制,复制mesh到mesh2

File inputFile = new File("D:\\file\\mesh.txt");

File outFile = new File("D:\\file\\mesh2.txt");

FileInputStream fileInputStream = new FileInputStream(inputFile);

FileOutputStream fileOutputStream = new FileOutputStream(outFile);

byte[] bytes = new byte[1024]; //每次读的字节

int len=0;

while((len=fileInputStream.read(bytes))!=-1){

    fileOutputStream.write(bytes,0,len);

}

fileOutputStream.close();

fileInputStream.close();

2.缓冲流方式处理

File inputFile = new File("D:\\file\\mesh.txt");

File outFile = new File("D:\\file\\mesh2.txt");

FileInputStream fileInputStream = new FileInputStream(inputFile);

FileOutputStream fileOutputStream = new FileOutputStream(outFile);

BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);

byte[] bytes = new byte[1024]; //每次读的字节

int len=0;

while((len=bufferedInputStream.read(bytes))!=-1){

    bufferedOutputStream.write(bytes,0,len);

}

bufferedOutputStream.close();

bufferedInputStream.close();

fileOutputStream.close();

fileInputStream.close();